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1. Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field

Author: G. Revet, B. Khiar, E. Filippov, C. Argiroffi, J. Béard, R. Bonito, M. Cerchez, S. N. Chen, T. Gangolf, D. P. Higginson, A. Mignone, B. Olmi, M. Ouillé, S. N. Ryazantsev, I. Yu. Skobelev, M. I. Safronova, M. Starodubtsev, T. Vinci, O. Willi, S. Pikuz, S. Orlando, A. Ciardi, and J. Fuchs
Subjects: Science
Abstract: Mass outflow is a common process in astrophysical objects. Here the authors investigate in which conditions an astrophysically-scaled laser-produced plasma flow can be collimated and evolves in the presence of a misaligned external magnetic field.
Published: 2021
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2. Detailed characterization of a laboratory magnetized supercritical collisionless shock and of the associated proton energization

Author: W. Yao, A. Fazzini, S. N. Chen, K. Burdonov, P. Antici, J. Béard, S. Bolaños, A. Ciardi, R. Diab, E. D. Filippov, S. Kisyov, V. Lelasseux, M. Miceli, Q. Moreno, V. Nastasa, S. Orlando, S. Pikuz, D. C. Popescu, G. Revet, X. Ribeyre, E. d’Humières, and J. Fuchs
Subjects: Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of nonthermal particles and high-energy radiation. In the absence of particle collisions in the system, theory shows that the interaction of an expanding plasma with a pre-existing electromagnetic structure (as in our case) is able to induce energy dissipation and allow shock formation. Shock formation can alternatively take place when two plasmas interact, through microscopic instabilities inducing electromagnetic fields that are able in turn to mediate energy dissipation and shock formation. Using our platform in which we couple a rapidly expanding plasma induced by high-power lasers (JLF/Titan at LLNL and LULI2000) with high-strength magnetic fields, we have investigated the generation of a magnetized collisionless shock and the associated particle energization. We have characterized the shock as being collisionless and supercritical. We report here on measurements of the plasma density and temperature, the electromagnetic field structures, and the particle energization in the experiments, under various conditions of ambient plasma and magnetic field. We have also modeled the formation of the shocks using macroscopic hydrodynamic simulations and the associated particle acceleration using kinetic particle-in-cell simulations. As a companion paper to Yao et al. [Nat. Phys. 17, 1177–1182 (2021)], here we show additional results of the experiments and simulations, providing more information to allow their reproduction and to demonstrate the robustness of our interpretation of the proton energization mechanism as being shock surfing acceleration.
Published: 2022
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3. Highly-collimated, high-charge and broadband MeV electron beams produced by magnetizing solids irradiated by high-intensity lasers

Author: S. Bolaños, J. Béard, G. Revet, S. N. Chen, S. Pikuz, E. Filippov, M. Safronova, M. Cerchez, O. Willi, M. Starodubtsev, and J. Fuchs
Subjects: Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Laser irradiation of solid targets can drive short and high-charge relativistic electron bunches over micron-scale acceleration gradients. However, for a long time, this technique was not considered a viable means of electron acceleration due to the large intrinsic divergence (∼50° half-angle) of the electrons. Recently, a reduction in this divergence to 10°–20° half-angle has been obtained, using plasma-based magnetic fields or very high contrast laser pulses to extract the electrons into the vacuum. Here we show that we can further improve the electron beam collimation, down to ∼1.5° half-angle, of a high-charge (6 nC) beam, and in a highly reproducible manner, while using standard stand-alone 100 TW-class laser pulses. This is obtained by embedding the laser-target interaction in an external, large-scale (cm), homogeneous, extremely stable, and high-strength (20 T) magnetic field that is independent of the laser. With upcoming multi-PW, high repetition-rate lasers, this technique opens the door to achieving even higher charges (>100 nC).
Published: 2019
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4. Investigating particle acceleration dynamics in interpenetrating magnetized collisionless super-critical shocks

Author: W. Yao, A. Fazzini, S.N. Chen, K. Burdonov, J. Béard, M. Borghesi, A. Ciardi, M. Miceli, S. Orlando, X. Ribeyre, E. d'Humières, J. Fuchs, W. Yao, A. Fazzini, S.N. Chen, K. Burdonov, J. B??ard, M. Borghesi, A. Ciardi, M. Miceli, S. Orlando, X. Ribeyre, E. d'Humi??re, J. Fuchs, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre d'Etudes Lasers Intenses et Applications (CELIA), and Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Plasma Physics (physics.plasm-ph), Settore FIS/05 - Astronomia E Astrofisica, plasma simulation, FOS: Physical sciences, Condensed Matter Physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], plasma nonlinear phenomena, Physics - Plasma Physics, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph]
Abstract: Colliding collisionless shocks appear in a great variety of astrophysical phenomena and are thought to be possible sources of particle acceleration in the Universe. We have previously investigated particle acceleration induced by single super-critical shocks (whose magnetosonic Mach number is higher than the critical value of 2.7) (Yao et al., Nat. Phys., vol. 17, issue 10, 2021, pp. 1177–1182; Yao et al., Matter Radiat. Extrem., vol. 7, issue 1, 2022, 014402), as well as the collision of two sub-critical shocks (Fazzini et al., Astron. Astrophys., vol. 665, 2022, A87). Here, we propose to make measurements of accelerated particles from interpenetrating super-critical shocks to observe the ‘phase-locking effect’ (Fazzini et al., Astron. Astrophys., vol. 665, 2022, A87) from such an event. This effect is predicted to significantly boost the energy spectrum of the energized ions compared with a single super-critical collisionless shock. We thus anticipate that the results obtained in the proposed experiment could have a significant impact on our understanding of one type of primary source (acceleration of thermal ions as opposed to secondary acceleration mechanisms of already energetic ions) of ion energization of particles in the Universe.
Published: 2023

5. Detailed characterization of laboratory magnetized super-critical collisionless shock and of the associated proton energization

Author: W. Yao, A. Fazzini, S. N. Chen, K. Burdonov, P. Antici, J. Béard, S. Bolaños, A. Ciardi, R. Diab, E. D. Filippov, S. Kisyov, V. Lelasseux, M. Miceli, Q. Moreno, V. Nastasa, S. Orlando, S. Pikuz, D. C. Popescu, G. Revet, X. Ribeyre, E. d’Humières, J. Fuchs, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Horia Hulubei National Institute for Physics and Nuclear Engineering, IAP, Russian Academy of Sciences, 603155, Nizhny Novgorod, Russia, Énergie Matériaux Télécommunications - INRS (EMT-INRS), Institut National de la Recherche Scientifique [Québec] (INRS)-Université du Québec à Montréal = University of Québec in Montréal (UQAM), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Università degli studi di Palermo - University of Palermo, INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Centre d'Etudes Lasers Intenses et Applications (CELIA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institute of Physics of the Czech Academy of Sciences (FZU / CAS), Czech Academy of Sciences [Prague] (CAS), Moscow State Engineering Physics Institute (MEPhI), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Yao W., Fazzini A., Chen S.N., Burdonov K., Antici P., Beard J., Bolanos S., Ciardi A., Diab R., Filippov E.D., Kisyov S., Lelasseux V., Miceli M., Moreno Q., Nastasa V., Orlando S., Pikuz S., Popescu D.C., Revet G., Ribeyre X., D'Humieres E., and Fuchs J.
Subjects: Nuclear and High Energy Physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, magnetic field, QC770-798, shock waves, 01 natural sciences, Atomic and Molecular Physics, and Optics, Physics - Plasma Physics, 010305 fluids & plasmas, Plasma Physics (physics.plasm-ph), Settore FIS/05 - Astronomia E Astrofisica, Nuclear Energy and Engineering, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Nuclear and particle physics. Atomic energy. Radioactivity, 0103 physical sciences, Physics::Space Physics, Electrical and Electronic Engineering, 010306 general physics
Abstract: Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of nonthermal particles and high-energy radiation. In the absence of particle collisions in the system, theory shows that the interaction of an expanding plasma with a pre-existing electromagnetic structure (as in our case) is able to induce energy dissipation and allow shock formation. Shock formation can alternatively take place when two plasmas interact, through microscopic instabilities inducing electromagnetic fields that are able in turn to mediate energy dissipation and shock formation. Using our platform in which we couple a rapidly expanding plasma induced by high-power lasers (JLF/Titan at LLNL and LULI2000) with high-strength magnetic fields, we have investigated the generation of a magnetized collisionless shock and the associated particle energization. We have characterized the shock as being collisionless and supercritical. We report here on measurements of the plasma density and temperature, the electromagnetic field structures, and the particle energization in the experiments, under various conditions of ambient plasma and magnetic field. We have also modeled the formation of the shocks using macroscopic hydrodynamic simulations and the associated particle acceleration using kinetic particle-in-cell simulations. As a companion paper to Yao et al. [Nat. Phys. 17, 1177–1182 (2021)], here we show additional results of the experiments and simulations, providing more information to allow their reproduction and to demonstrate the robustness of our interpretation of the proton energization mechanism as being shock surfing acceleration.
Published: 2022

6. Inferring possible magnetic field strength of accreting inflows in EXor-type objects from scaled laboratory experiments

Author: Mikhail Gushchin, Rosaria Bonito, K. Gubskiy, Efim A. Khazanov, Julien Fuchs, A. V. Strikovskiy, V. I. Gundorin, A. Kuznetsov, S. N. Ryazantsev, S. A. Pikuz, Salvatore Orlando, Alexander Soloviev, W. P. Yao, I. Shaykin, Teresa Giannini, R. Zemskov, Ivan V. Yakovlev, Shihua Chen, N. A. Aidakina, I. Zudin, Andrey Shaykin, M. V. Starodubtsev, Vladislav Ginzburg, K. Burdonov, A. A. Kuzmin, J. Béard, G. Revet, A. A. Kochetkov, Andrea Ciardi, S. V. Korobkov, Costanza Argiroffi, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institute of Applied Physics of RAS, Russian Academy of Sciences [Moscow] (RAS), INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Roma (OAR), Università degli studi di Palermo - University of Palermo, Horia Hulubei National Institute for Physics and Nuclear Engineering, Moscow State Engineering Physics Institute (MEPhI), Joint Institute for High Temperatures of the RAS (JIHT), The National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) [Moscow, Russia], This work was partly done within the LABEX Plas@Par, the DIM ACAV funded by the Region Ile-de-France, and supported by Grant No. 11-IDEX- 0004-02 from ANR, The research leading to these results is supported by Extreme Light Infrastructure Nuclear Physics (ELINP) Phase II, a project co-financed by the Romanian Government and European Union through the European Regional Development Fund, and by the project ELI-RO-2020-23 funded by IFA (Romania)., European Project: ERC787539,GENESIS, Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), HEP, INSPIRE, Burdonov K., Bonito R., Giannini T., Aidakina N., Argiroffi C., Beard J., Chen S.N., Ciardi A., Ginzburg V., Gubskiy K., Gundorin V., Gushchin M., Kochetkov A., Korobkov S., Kuzmin A., Kuznetsov A., Pikuz S., Revet G., Ryazantsev S., Shaykin A., Shaykin I., Soloviev A., Starodubtsev M., Strikovskiy A., Yao W., Yakovlev I., Zemskov R., Zudin I., Khazanov E., Orlando S., and Fuchs J.
Subjects: Shock wave, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Field strength, Astrophysics, stars: pre-main sequence, 01 natural sciences, magnetohydrodynamics (MHD), Settore FIS/05 - Astronomia E Astrofisica, accretion, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, [PHYS]Physics [physics], accretion disks, Astronomy and Astrophysics, Radius, Plasma, shock waves, Accretion, accretion disks, Accretion (astrophysics), Magnetic field, T Tauri star, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, instabilities, stars: individual: V1118 Ori, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Aims. EXor-type objects are protostars that display powerful UV-optical outbursts caused by intermittent and powerful events of magnetospheric accretion. These objects are not yet well investigated and are quite difficult to characterize. Several parameters, such as plasma stream velocities, characteristic densities, and temperatures, can be retrieved from present observations. As of yet, however, there is no information about the magnetic field values and the exact underlying accretion scenario is also under discussion. Methods. We use laboratory plasmas, created by a high power laser impacting a solid target or by a plasma gun injector, and make these plasmas propagate perpendicularly to a strong external magnetic field. The propagating plasmas are found to be well scaled to the presently inferred parameters of EXor-type accretion event, thus allowing us to study the behaviour of such episodic accretion processes in scaled conditions. Results. We propose a scenario of additional matter accretion in the equatorial plane, which claims to explain the increased accretion rates of the EXor objects, supported by the experimental demonstration of effective plasma propagation across the magnetic field. In particular, our laboratory investigation allows us to determine that the field strength in the accretion stream of EXor objects, in a position intermediate between the truncation radius and the stellar surface, should be of the order of 100 G. This, in turn, suggests a field strength of a few kilogausses on the stellar surface, which is similar to values inferred from observations of classical T Tauri stars.
Published: 2021

7. Laboratory evidence for proton energization by collisionless shock surfing

Author: G. Revet, K. Burdonov, J. Béard, A. Fazzini, E. D. Filippov, S. Bolaños, Julien Fuchs, V. Lelasseux, S. A. Pikuz, D. C. Popescu, Salvatore Orlando, W. P. Yao, V. Nastasa, Patrizio Antici, Andrea Ciardi, S. Kisyov, Quentin Moreno, Marco Miceli, Xavier Ribeyre, Emmanuel d'Humières, R. Diab, Sophia Chen, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre d'Etudes Lasers Intenses et Applications (CELIA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ITA, FRA, CAN, CZE, ROU, RUS, Yao W., Fazzini A., Chen S.N., Burdonov K., Antici P., Beard J., Bolanos S., Ciardi A., Diab R., Filippov E.D., Kisyov S., Lelasseux V., Miceli M., Moreno Q., Nastasa V., Orlando S., Pikuz S., Popescu D.C., Revet G., Ribeyre X., d'Humieres E., Fuchs J., Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB)
Subjects: Shock wave, Proton, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Acceleration, Settore FIS/05 - Astronomia E Astrofisica, 0103 physical sciences, Bow shock (aerodynamics), 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Mechanics, plasmas, Physics - Plasma Physics, Charged particle, Computer Science::Computers and Society, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Magnetic field, Shock (mechanics), Plasma Physics (physics.plasm-ph), Supernova, 13. Climate action, Physics::Space Physics, Physics::Accelerator Physics
Abstract: Charged particles can be accelerated to high energies by collisionless shock waves in astrophysical environments, such as supernova remnants. By interacting with the magnetized ambient medium, these shocks can transfer energy to particles. Despite increasing efforts in the characterization of these shocks from satellite measurements at Earth’s bow shock as well as powerful numerical simulations, the underlying acceleration mechanism or a combination thereof is still widely debated. Here we show that astrophysically relevant super-critical quasi-perpendicular magnetized collisionless shocks can be produced and characterized in the laboratory. We observe the characteristics of super-criticality in the shock profile as well as the energization of protons picked up from the ambient gas to hundreds of kiloelectronvolts. Kinetic simulations modelling the laboratory experiment identified shock surfing as the proton acceleration mechanism. Our observations not only provide direct evidence of early-stage ion energization by collisionless shocks but also highlight the role played by this particular mechanism in energizing ambient ions to feed further stages of acceleration. Furthermore, our results open the door to future laboratory experiments investigating the possible transition to other mechanisms, when increasing the magnetic field strength, or the effect that induced shock front ripples could have on acceleration processes. Proton acceleration by a super-critical collisionless shock is observed in laboratory experiments, and numerical simulations suggest shock surfing as the underlying acceleration mechanism.
Published: 2021

8. A novel pulsed magnet for magnetic linear birefringence measurements

Author: J. Béard, R. Battesti, Carlo Rizzo, Jonathan Agil, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Linear birefringence, noise, Physics - Instrumentation and Detectors, Materials science, Field (physics), FOS: Physical sciences, 01 natural sciences, 010309 optics, Optics, Sensitivity, electromagnetic field, 0103 physical sciences, quantum electrodynamics, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Instrumentation, FOIL method, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Birefringence, business.industry, Instrumentation and Detectors (physics.ins-det), [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Pulse (physics), Transverse plane, pulsed magnetic field, Electromagnetic coil, Pulsed magnet, business, Optics (physics.optics), Physics - Optics, experimental results
Abstract: International audience; In this paper, we describe a novel pulsed magnet, called foil coil, which can deliver a field transverse to the light propagation of more than 10 T over about 0.8 m operating without cryogenic equipment. It has been designed for linear magnetic birefringence measurements. We report on testing the coil and also show some physics data taken in vacuum during its commissioning in the framework of the Biréfringence Magnétique du Vide (BMV) apparatus, with special attention to noise induced by the pulse itself. Finally, we compare the preliminary results obtained here with data from the previous BMV coil.
Published: 2021

9. Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field

Author: Mirela Cerchez, Drew Higginson, E. D. Filippov, T. Gangolf, S. A. Pikuz, I. Yu. Skobelev, B. Khiar, G. Revet, Tommaso Vinci, B. Olmi, Salvatore Orlando, J. Béard, O. Willi, Rosaria Bonito, M. V. Starodubtsev, Costanza Argiroffi, M. Safronova, M. Ouillé, S. N. Ryazantsev, Julien Fuchs, Andrea Ciardi, Andrea Mignone, Sophia Chen, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institute of Applied Physics (IAP, Nizhny Novgorod), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Flash Center for Computational Science (FCCS), University of Chicago, Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Dipartimento di Fisica e Chimica [Palermo] (DiFC), Università degli studi di Palermo - University of Palermo, INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut für Laser und Plasmaphysik, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Horia Hulubei Natl Inst Phys & Nucl Engn IFIN HH, ELI NP Dept, Reactorului Str 30, Magurele 077125, Romania, Lawrence Livermore National Laboratory (LLNL), Dipartimento di Fisica Generale, Università di Torino, INAF - Osservatorio Astrofisico di Arcetri (OAA), The National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) [Moscow, Russia], Revet G., Khiar B., Filippov E., Argiroffi C., Beard J., Bonito R., Cerchez M., Chen S.N., Gangolf T., Higginson D.P., Mignone A., Olmi B., Ouille M., Ryazantsev S.N., Skobelev I.Y., Safronova M.I., Starodubtsev M., Vinci T., Willi O., Pikuz S., Orlando S., Ciardi A., and Fuchs J.
Subjects: Science, Astrophysics::High Energy Astrophysical Phenomena, Nozzle, outflows, magnetohydrodynamics(MHD), shockwaves, astrophysical jets, General Physics and Astronomy, FOS: Physical sciences, Astrophysics, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Collimated light, Settore FIS/05 - Astronomia E Astrofisica, Ambient field, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Magnetic pressure, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Laboratory astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Jet (fluid), Multidisciplinary, Laser-produced plasmas, General Chemistry, Physics - Plasma Physics, Magnetic field, Plasma Physics (physics.plasm-ph), Astrophysics - Solar and Stellar Astrophysics, Physics::Accelerator Physics, Outflow, High Energy Physics::Experiment, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The shaping of astrophysical outflows into bright, dense, and collimated jets due to magnetic pressure is here investigated using laboratory experiments. Here we look at the impact on jet collimation of a misalignment between the outflow, as it stems from the source, and the magnetic field. For small misalignments, a magnetic nozzle forms and redirects the outflow in a collimated jet. For growing misalignments, this nozzle becomes increasingly asymmetric, disrupting jet formation. Our results thus suggest outflow/magnetic field misalignment to be a plausible key process regulating jet collimation in a variety of objects from our Sun’s outflows to extragalatic jets. Furthermore, they provide a possible interpretation for the observed structuring of astrophysical jets. Jet modulation could be interpreted as the signature of changes over time in the outflow/ambient field angle, and the change in the direction of the jet could be the signature of changes in the direction of the ambient field., Mass outflow is a common process in astrophysical objects. Here the authors investigate in which conditions an astrophysically-scaled laser-produced plasma flow can be collimated and evolves in the presence of a misaligned external magnetic field.
Published: 2021

10. The Divided States : Unraveling National Identities in the Twenty-First Century

Author: Laura J. Beard, Ricia Anne Chansky, Laura J. Beard, and Ricia Anne Chansky
Subjects: Autobiography, American prose literature--21st century--History and criticism, National characteristics, American
Abstract: What is an “American” identity? The tension between populism and pluralism, between homogeneity and heterogeneity, has marked the United States since its inception. In The Divided States, leading scholars and critics argue that the US is, and has always been, a site where multiple national identities intersect in productive and challenging ways. Scrutinizing conflicting nationalisms and national identities, the authors ask, Whose stories get told and whose do not? Who or what promotes the idea of a unified national identity in the United States? How is the notion of a unified national identity disrupted? What myths and stories bind the US together? How representative are these stories? What are the counternarratives? And, if the idea of national homogeneity is a fallacy, what does tie us together as a nation? Working across auto/biography studies, American studies, and human geography—all of which deal with the current interest in competing narratives, “alternative facts,” and accountability—the essays engage in and contribute to critical conversations in classrooms, scholarship, and the public sphere. The authors draw from a variety of fields, including anthropology; class analysis; critical race theory; diasporic, refugee, and immigration studies; disability studies; gender studies; graphic and comix studies; Indigenous studies; linguistics; literary studies; sociology; and visual culture. And the genres under scrutiny include diary, epistolary communication, digital narratives, graphic narratives, literary narratives, medical narratives, memoir, oral history, and testimony. This fresh and theoretically engaged volume will be relevant to anyone interested in the multiplicity of voices that make up the US national narrative.
Published: 2023

11. Enhanced x-ray emission arising from laser-plasma confinement by a strong transverse magnetic field

Author: Amira Guediche, Julien Fuchs, S. A. Pikuz, J. Béard, K. F. Burdonov, S. Bolaños, W. P. Yao, M. V. Starodubtsev, Jack Hare, E. D. Filippov, G. Revet, Igor Yu. Skobelev, Denis Romanovsky, Sophia Chen, S. S. Makarov, Andrea Ciardi, University of Nizhny Novgorod, Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Lomonosov Moscow State University (MSU), Institute of Applied Physics of RAS, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Horia Hulubei National Institute for Physics and Nuclear Engineering, Imperial College London, The National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) [Moscow, Russia], Lobachevsky State University [Nizhni Novgorod], Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)
Subjects: Materials science, Science, FOS: Physical sciences, Magnetically confined plasmas, 01 natural sciences, Article, 010305 fluids & plasmas, law.invention, Magnetization, law, Physics::Plasma Physics, 0103 physical sciences, Emissivity, Radiative transfer, 010306 general physics, [PHYS]Physics [physics], Multidisciplinary, Laser-produced plasmas, Plasma, Laser, Physics - Plasma Physics, Magnetic field, Plasma Physics (physics.plasm-ph), Transverse plane, Physics::Space Physics, Medicine, Atomic physics, Magnetohydrodynamics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We analyze, using experiments and 3D MHD numerical simulations, the dynamics and radiative properties of a plasma ablated by a laser (1 ns, 10$^{12}$-10$^{13}$ W/cm$^2$) from a solid target, as it expands into a homogeneous, strong magnetic field (up to 30 T) transverse to its main expansion axis. We find that as soon as 2 ns after the start of the expansion, the plasma becomes constrained by the magnetic field. As the magnetic field strength is increased, more plasma is confined close to the target and is heated by magnetic compression. We also observe a dense slab that rapidly expands into vacuum after ~ 8 ns; however, this slab contains only ~ 2 % of the total plasma. As a result of the higher density and increased heating of the confined plasma, there is a net enhancement of the total x-ray emissivity induced by the magnetization., 15 pages, 4 figures, Supplementary Information, submitted to PRL
Published: 2020

12. Laboratory evidence for asymmetric accretion structure upon slanted matter impact in young stars

Author: Rosaria Bonito, Salvatore Orlando, O. Willi, Julien Fuchs, S. N. Chen, K. F. Burdonov, Mirela Cerchez, J. Béard, G. Revet, S. A. Pikuz, M. V. Starodubtsev, Rafael L. Rodríguez, E. D. Filippov, Costanza Argiroffi, Andrea Ciardi, G. Espinosa, S. Bolanos, Michal Smid, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Burdonov K., Revet G., Bonito R., Argiroffi C., Beard J., Bolanos S., Cerchez M., Chen S.N., Ciardi A., Espinosa G., Filippov E., Pikuz S., Rodriguez R., Smid M., Starodubtsev M., Willi O., Orlando S., Fuchs J., Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Università degli studi di Palermo - University of Palermo, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Horia Hulubei National Institute for Physics and Nuclear Engineering, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Universidad de las Palmas de Gran Canaria (ULPGC), Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Institute of Applied Physics (IAP, Nizhny Novgorod), Moscow State Engineering Physics Institute (MEPhI), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), This work was partly done within the LABEX Plas@Par, the DIM ACAV funded by the Region Ilede-France, This work was supported by Grant No. 11-IDEX- 0004-02 from ANR (France), ANR-12-BS09-0025,SILAMPA,Simuler en laboratoire des écoulements de plasmas magnétisés pour l'astrophysique(2012), European Project: ERC787539,GENESIS, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Shock wave, stars, Accretion, Magnetohydrodynamics (MHD), Young stellar object, FOS: Physical sciences, X-rays: stars, Astrophysics, 01 natural sciences, Shock waves, Settore FIS/05 - Astronomia E Astrofisica, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, Ejecta, 010303 astronomy & astrophysics, Chromosphere, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, pre-main sequence -X-rays, Astronomy and Astrophysics, Plasma, Planetary system, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], accretion disks -instabilities -magnetohydrodynamics (MHD) -shock waves -stars, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Instabilities, Accretion disks, Stars: pre-main sequence, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Aims. Investigating the process of matter accretion onto forming stars through scaled experiments in the laboratory is important in order to better understand star and planetary system formation and evolution. Such experiments can indeed complement observations by providing access to the processes with spatial and temporal resolution. A previous investigation revealed the existence of a two-component stream: a hot shell surrounding a cooler inner stream. The shell was formed by matter laterally ejected upon impact and refocused by the local magnetic field. That laboratory investigation was limited to normal incidence impacts. However, in young stellar objects, the complex structure of magnetic fields causes variability of the incident angles of the accretion columns. This led us to undertake an investigation, using laboratory plasmas, of the consequence of having a slanted accretion impacting a young star. Methods. Here, we used high power laser interactions and strong magnetic field generation in the laboratory, complemented by numerical simulations, to study the asymmetry induced upon accretion structures when columns of matter impact the surface of young stars with an oblique angle. Results. Compared to the scenario where matter accretes perpendicularly to the star surface, we observe a strongly asymmetric plasma structure, strong lateral ejecta of matter, poor confinement of the accreted material, and reduced heating compared to the normal incidence case. Thus, slanted accretion is a configuration that seems to be capable of inducing perturbations of the chromosphere and hence possibly influencing the level of activity of the corona.
Published: 2020

13. Laboratory investigation of particle acceleration and magnetic field compression in collisionless colliding fast plasma flows

Author: D. P. Higginson, Ph. Korneev, C. Ruyer, R. Riquier, Q. Moreno, J. Béard, S. N. Chen, A. Grassi, M. Grech, L. Gremillet, H. Pépin, F. Perez, S. Pikuz, B. Pollock, C. Riconda, R. Shepherd, M. Starodubtsev, V. Tikhonchuk, T. Vinci, E. d’Humières, J. Fuchs, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lawrence Livermore National Laboratory (LLNL), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Énergie Matériaux Télécommunications - INRS (EMT-INRS), Institut National de la Recherche Scientifique [Québec] (INRS)-Université du Québec à Montréal = University of Québec in Montréal (UQAM), Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Institute of Applied Physics (IAP, Nizhny Novgorod), Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), ANR-12-BS09-0025,SILAMPA,Simuler en laboratoire des écoulements de plasmas magnétisés pour l'astrophysique(2012), ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011), European Project: ERC787539,GENESIS, European Project: AWP15-ENR-01/CEA-02,EUROFusion - ToIFE, European Project: 654148,H2020,H2020-INFRAIA-2014-2015,LASERLAB-EUROPE(2015), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], lcsh:QB460-466, lcsh:Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], lcsh:Physics, lcsh:QC1-999, ComputingMilieux_MISCELLANEOUS
Abstract: Ion production and acceleration is ubiquitous in astrophysical objects but many questions still remain on the mechanisms at play and while laboratory plasmas provide an “accessible” regime, non-thermal ion acceleration has not been observed in the laboratory before the advent of high-power lasers. The authors collide two relativistic plasma flows and observe large energy difference of the protons coming out of the interaction region with or without an external magnetic field, qualitatively corroborating their 1D and 2D particle-in-cell simulations.
Published: 2019

14. Highly-collimated, high-charge and broadband MeV electron beams produced by magnetizing solids irradiated by high-intensity lasers

Author: G. Revet, M. Safronova, Oswald Willi, Mirela Cerchez, J. Béard, Sophia Chen, Julien Fuchs, M. V. Starodubtsev, E. D. Filippov, S. A. Pikuz, S. Bolanos, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institute of Applied Physics of RAS, Russian Academy of Sciences [Moscow] (RAS), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Joint Institute for High Temperatures of the RAS (JIHT), The National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) [Moscow, Russia], Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011), ANR-17-CE30-0026,PiNNaCLE,Développement d'une ligne de neutrons pulsés compacte et de haute brillance(2017), European Project: 654148,H2020,H2020-INFRAIA-2014-2015,LASERLAB-EUROPE(2015), European Project: ERC787539,GENESIS, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and National Research Nuclear University MEPhI
Subjects: Nuclear and High Energy Physics, Materials science, Electron, Plasma, Laser, 01 natural sciences, Atomic and Molecular Physics, and Optics, Collimated light, 010305 fluids & plasmas, Magnetic field, law.invention, Acceleration, Nuclear Energy and Engineering, law, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Cathode ray, lcsh:QC770-798, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Electrical and Electronic Engineering, Atomic physics, 010306 general physics, Beam (structure), ComputingMilieux_MISCELLANEOUS
Abstract: Laser irradiation of solid targets can drive short and high-charge relativistic electron bunches over micron-scale acceleration gradients. However, for a long time, this technique was not considered a viable means of electron acceleration due to the large intrinsic divergence (∼50° half-angle) of the electrons. Recently, a reduction in this divergence to 10°–20° half-angle has been obtained, using plasma-based magnetic fields or very high contrast laser pulses to extract the electrons into the vacuum. Here we show that we can further improve the electron beam collimation, down to ∼1.5° half-angle, of a high-charge (6 nC) beam, and in a highly reproducible manner, while using standard stand-alone 100 TW-class laser pulses. This is obtained by embedding the laser-target interaction in an external, large-scale (cm), homogeneous, extremely stable, and high-strength (20 T) magnetic field that is independent of the laser. With upcoming multi-PW, high repetition-rate lasers, this technique opens the door to achieving even higher charges (>100 nC).Laser irradiation of solid targets can drive short and high-charge relativistic electron bunches over micron-scale acceleration gradients. However, for a long time, this technique was not considered a viable means of electron acceleration due to the large intrinsic divergence (∼50° half-angle) of the electrons. Recently, a reduction in this divergence to 10°–20° half-angle has been obtained, using plasma-based magnetic fields or very high contrast laser pulses to extract the electrons into the vacuum. Here we show that we can further improve the electron beam collimation, down to ∼1.5° half-angle, of a high-charge (6 nC) beam, and in a highly reproducible manner, while using standard stand-alone 100 TW-class laser pulses. This is obtained by embedding the laser-target interaction in an external, large-scale (cm), homogeneous, extremely stable, and high-strength (20 T) magnetic field that is independent of t...
Published: 2019

15. Overt and covert paths for sound in the auditory system of mammals

Author: B. Auriol, J. Béard, B. Bibé, J.-M. Broto, D.F. Descouens, L.J.S. Durand, J.-P. Florens, F. Garcia, C. Gillieaux, E.G. Joiner, B. Libes, P. Pergent, R. Ruiz, C. Thalamas, Théâtre du Capitol, Partenaires INRAE, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Toulouse School of Economics (TSE-R), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-École des hautes études en sciences sociales (EHESS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Unité de Mathématiques et Informatique Appliquées de Toulouse (MIAT INRA), Institut National de la Recherche Agronomique (INRA), Montel Veterinary Clinic, Department of Languages, Literatures, and Cultures, The University of South Carolina, Centre Hospitalier Universitaire de Toulouse (CHU Toulouse), Veterinary Doctor, Laboratoire de Recherche en Audiovisuel - Savoirs, Praxis et Poïétiques en Art (LARA-SEPPIA ), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT), Centre d'investigation clinique de Toulouse (CIC 1436), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Pôle Santé publique et médecine publique [CHU Toulouse], Centre Hospitalier Universitaire de Toulouse (CHU Toulouse)-Centre Hospitalier Universitaire de Toulouse (CHU Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Toulouse School of Economics (TSE), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-École des hautes études en sciences sociales (EHESS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), CRA, CHU Purpan, and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-CHU Toulouse [Toulouse]-Institut National de la Santé et de la Recherche Médicale (INSERM)
Subjects: Sound (medical instrument), 0303 health sciences, Ossicles, Computer science, Sound transmission class, Mechanism (biology), Tympanum (anatomy), 03 medical and health sciences, 0302 clinical medicine, medicine.anatomical_structure, Quality (physics), Covert, medicine, otorhinolaryngologic diseases, Auditory system, [INFO]Computer Science [cs], [MATH]Mathematics [math], Neuroscience, 030217 neurology & neurosurgery, Cochlea, 030304 developmental biology
Abstract: Current scientific consensus holds that sound is transmitted, solely mechanically, from the tympanum to the cochlea via ossicles.But this theory does not explain the hearing extreme quality regarding high frequencies in mammals. So, we propose a bioelectronic pathway (the covert path) that is complementary to the overt path.We demonstrate experimentally that the tympanum produces piezoelectric potentials isochronous to acoustic vibrations thanks to its collagen fibers and that their amplitude increases along with the frequency and level of the vibrations. This finding supports the existence of an electrical pathway, specialized in transmitting high-frequency sounds, that works in unison with the mechanical pathway. A bio-organic triode, similar to a field effect transistor, is the key mechanism of our hypothesized pathway. We present evidence that any deficiency along this pathway produces hearing impairment. By augmenting the classical theory of sound transmission, our discovery offers new perspectives for research into both normal and pathological audition and may contribute to an understanding of genetic and physiological problems of hearing.
Published: 2019

16. Laser experiment for the study of accretion dynamics of Young Stellar Objects: design and scaling

Author: G. Revet, Andrea Ciardi, M. V. Starodubtsev, J. Béard, Salvatore Orlando, Rosaria Bonito, B. Khiar, Julien Fuchs, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Istituto di Astrofisica Spaziale e Fisica cosmica - Palermo (IASF-Pa), Istituto Nazionale di Astrofisica (INAF), Institute of Applied Physics (IAP, Nizhny Novgorod), École normale supérieure - Paris (ENS-PSL), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, FRA, ROU, and RUS
Subjects: Nuclear and High Energy Physics, Young stellar object, FOS: Physical sciences, 01 natural sciences, 010305 fluids & plasmas, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, Adiabatic process, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Radiation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Plasma, Accretion (astrophysics), Physics - Plasma Physics, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Magnetic field, Computational physics, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Plasma Physics (physics.plasm-ph), Stars, T Tauri star, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: A new experimental set-up designed to investigate the accretion dynamics in newly born stars is presented. It takes advantage of a magnetically collimated stream produced by coupling a laser-generated expanding plasma to a $2\times 10^{5}~{G}\ (20~{T})$ externally applied magnetic field. The stream is used as the accretion column and is launched onto an obstacle target that mimics the stellar surface. This setup has been used to investigate in details the accretion dynamics, as reported in [G. Revet et al., Science Advances 3, e1700982 (2017), arXiv:1708.02528}. Here, the characteristics of the stream are detailed and a link between the experimental plasma expansion and a 1D adiabatic expansion model is presented. Dimensionless numbers are also calculated in order to characterize the experimental flow and its closeness to the ideal MHD regime. We build a bridge between our experimental plasma dynamics and the one taking place in the Classical T Tauri Stars (CTTSs), and we find that our set-up is representative of a high plasma $\beta$ CTTS accretion case.
Published: 2019
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17. Laser-Produced Magnetic-Rayleigh-Taylor Unstable Plasma Slabs in a 20 T Magnetic Field

Author: J. Béard, S. S. Makarov, Andrea Ciardi, Shihua Chen, Mirela Cerchez, E. D. Filippov, T. Gangolf, B. Khiar, G. Revet, S. A. Pikuz, Oswald Willi, M. Ouillé, A. A. Soloviev, Julien Fuchs, M. Safronova, K. F. Burdonov, M. V. Starodubtsev, I. Yu. Skobelev, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institute of Applied Physics (IAP, Nizhny Novgorod), Institut für Laser und Plasmaphysik, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Lobachevsky State University [Nizhni Novgorod], Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011), ANR-10-EQPX-0029,EQUIP@MESO,Equipement d'excellence de calcul intensif de Mesocentres coordonnés - Tremplin vers le calcul petaflopique et l'exascale(2010), ANR-11-LABX-0062,PLAS@PAR,PLASMAS à PARIS, au delà des frontières(2011), European Project: 787539,GENESIS - 10.3030/787539, and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Instability, Collimated light, law.invention, Physics::Fluid Dynamics, symbols.namesake, law, Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Rayleigh scattering, 010306 general physics, Inertial confinement fusion, ComputingMilieux_MISCELLANEOUS, Physics, Condensed matter physics, Plasma, Laser, Physics - Plasma Physics, Magnetic field, Plasma Physics (physics.plasm-ph), Physics::Space Physics, Slab, symbols
Abstract: Magnetized laser-produced plasmas are central to many novel laboratory astrophysics and inertial confinement fusion studies, as well as in industrial applications. Here we provide the first complete description of the three-dimensional dynamics of a laser-driven plasma plume expanding in a 20 T transverse magnetic field. The plasma is collimated by the magnetic field into a slender, rapidly elongating slab, whose plasma-vacuum interface is unstable to the growth of the "classical", fluid-like magnetized Rayleigh-Taylor instability., Comment: Accepted for publication in Physical Review Letters
Published: 2019
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18. The DNA of Physician Leadership : Creating Dynamic Executives

Author: Myron J. Beard, Steve Quach, Myron J. Beard, and Steve Quach
Subjects: Leadership
Abstract: Physicians are increasingly moving into leadership roles and possess enormous potential to advance health care. However, clinical training and practice does not provide the necessary skills for a transition from clinician into physician-leader. In fact, the very skills that make for an outstanding physician often compete, or interfere, with the skills required to be successful in wider leadership roles.The authors provide the aspiring physician-leader with the understanding of what is required to be a successful physician-leader and the tools necessary for the transition including: Understanding the business of health care; Recognizing physician-leader psychology; Establishing influence, the bedrock of leadership; Creating a compelling strategy; Developing high-performing teams; Delegating to maximize leadership impact; Communicating for effectiveness; Negotiating for maximum benefit.This book is practical and realistic with case studies and recommendations on how to make the changes necessary to transform into a successful and fulfilled physician-leader.
Published: 2019

19. Change of carrier density at the pseudogap critical point of a cuprate superconductor

Author: Wojciech Tabis, Ruixing Liang, Louis Taillefer, Francis Laliberte, Gael Grissonnanche, Sven Badoux, J. Béard, Cyril Proust, David Vignolles, D. A. Bonn, Walter Hardy, B. Vignolle, Nicolas Doiron-Leyraud, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Superconductivity (cond-mat.supr-con), Condensed Matter - Strongly Correlated Electrons, Charge ordering, Critical point (thermodynamics), Hall effect, Condensed Matter::Superconductivity, 0103 physical sciences, Antiferromagnetism, Cuprate, 010306 general physics, Condensed Matter::Quantum Gases, Superconductivity, Physics, Multidisciplinary, Strongly Correlated Electrons (cond-mat.str-el), Condensed matter physics, Condensed Matter - Superconductivity, Mott insulator, 021001 nanoscience & nanotechnology, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, Pseudogap
Abstract: Low-temperature measurements of the Hall effect in cuprate materials in which superconductivity is suppressed by high magnetic fields show that the pseudogap is not related to the charge ordering that has been seen at intermediate doping levels, but is instead linked to the antiferromagnetic Mott insulator at low doping. The possible origin of the enigmatic 'pseudogap' phase in the high-temperature superconductors comes into sharper focus in light of some new low-temperature Hall measurements at magnetic fields high enough to suppress the confounding effects of superconductivity. Louis Taillefer and colleagues are able to show that the psudogap is not, as some have suspected, related to the charge-ordering that has been seen at intermediate doping levels, but is instead linked to the Mott insulator state at low doping. The pseudogap is a partial gap in the electronic density of states that opens in the normal (non-superconducting) state of cuprate superconductors and whose origin is a long-standing puzzle. Its connection to the Mott insulator phase at low doping (hole concentration, p) remains ambiguous1 and its relation to the charge order2,3,4 that reconstructs the Fermi surface5,6 at intermediate doping is still unclear7,8,9,10. Here we use measurements of the Hall coefficient in magnetic fields up to 88 tesla to show that Fermi-surface reconstruction by charge order in the cuprate YBa2Cu3Oy ends sharply at a critical doping p = 0.16 that is distinctly lower than the pseudogap critical point p* = 0.19 (ref. 11). This shows that the pseudogap and charge order are separate phenomena. We find that the change in carrier density n from n = 1 + p in the conventional metal at high doping (ref. 12) to n = p at low doping (ref. 13) starts at the pseudogap critical point. This shows that the pseudogap and the antiferromagnetic Mott insulator are linked.
Published: 2016

20. A novel platform to study magnetized high-velocity collisionless shocks

Author: Ph. Korneev, Vladimir Tikhonchuk, B. B. Pollock, H. Pépin, Drew Higginson, S. A. Pikuz, Emmanuel d'Humières, R. Riquier, Sophia Chen, J. Béard, and Julien Fuchs
Subjects: Physics, Nuclear and High Energy Physics, Helmholtz coil, Radiation, Field (physics), Proton, Plasma, Electron, Laser, law.invention, Magnetic field, Acceleration, law, Atomic physics
Abstract: An experimental platform to study the interaction of two colliding high-velocity (0.01–0.2c; 0.05–20 MeV) proton plasmas in a high strength (20 T) magnetic field is introduced. This platform aims to study the collision of magnetized plasmas accelerated via the Target-Normal-Sheath-Acceleration mechanism and initially separated by distances of a few hundred microns. The plasmas are accelerated from solid targets positioned inside a few cubic millimeter cavity located within a Helmholtz coil that provides up to 20 T magnetic fields. Various parameters of the plasmas at their interaction location are estimated. These show an interaction that is highly non-collisional, and that becomes more and more dominated by the magnetic fields as time progresses (from 5 to 60 ps). Particle-in-cell simulations are used to reproduce the initial acceleration of the plasma both via simulations including the laser interaction and via simulations that start with preheated electrons (to save dramatically on computational expense). The benchmarking of such simulations with the experiment and with each other will be used to understand the physical interaction when a magnetic field is applied. In conclusion, the experimental density profile of the interacting plasmas is shown in the case without an applied magnetic magnetic field, so to show thatmore » without an applied field that the development of high-velocity shocks, as a result of particle-to-particle collisions, is not achievable in the configuration considered.« less
Published: 2015

21. High magnetic fields for fundamental physics

Author: I. G. Irastorza, Ziad Melhem, Arran Phipps, Mikhail Kozlov, Toshiaki Inada, Pierre Pugnat, Geert L. J. A. Rikken, E. J. Daw, Victor V. Flambaum, Felix Karbstein, Herman H.J. ten Kate, J. Béard, Nicolas Bruyant, Sebastian Böser, Matthias Schott, Scott A. Crooker, Yannis K. Semertzidis, Dmitry Budker, Guido Zavattini, Carlo Rizzo, Remy Battesti, Dong Lak Kim, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Grenoble Alpes (UGA), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Toulouse ( LNCMI ), Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire national des champs magnétiques intenses - Grenoble ( LNCMI ), Centre National de la Recherche Scientifique ( CNRS ), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Helmholtz Institute Mainz (HIM), Department of Physics [Berkeley], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), and Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G )
Subjects: Astrophysics and Astronomy, Physics - Instrumentation and Detectors, magnet: design, magnetic field: high, Atomic Physics (physics.atom-ph), Axions, Dark matter, Complex system, Other Fields of Physics, FOS: Physical sciences, General Physics and Astronomy, 01 natural sciences, physics.atom-ph, NO, Physics - Atomic Physics, Nuclear physics, Physics and Astronomy (all), Neutrino mass, 0103 physical sciences, [ PHYS.PHYS.PHYS-GEN-PH ] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], High-field magnets, Spectroscopy, Vacuum birefringence, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Detectors and Experimental Techniques, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), [ PHYS.PHYS.PHYS-INS-DET ] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Axion, physics.ins-det, activity report, Exotic atom, Physics, 010308 nuclear & particles physics, Instrumentation and Detectors (physics.ins-det), Polarization (waves), magnet: technology, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], 3. Good health, Magnetic field, Antimatter, Magnet, Astrophysics - Instrumentation and Methods for Astrophysics, astro-ph.IM
Abstract: Various fundamental-physics experiments such as measurement of the birefringence of the vacuum, searches for ultralight dark matter (e.g., axions), and precision spectroscopy of complex systems (including exotic atoms containing antimatter constituents) are enabled by high-field magnets. We give an overview of current and future experiments and discuss the state-of-the-art DC- and pulsed-magnet technologies and prospects for future developments., 49 pages, 32 figures
Published: 2018

22. 40-tesla pulsed-field cryomagnet for single crystal neutron diffraction

Author: Bertrand Rollet, B. Longuet, E. Lelièvre-Berna, Xavier Tonon, J. E. Lorenzo, P. Frings, F. Mantegazza, J. Billette, Louis-Pierre Regnault, Fabienne Duc, J. Béard, William Knafo, Frederic Bourdarot, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut Laue-Langevin (ILL), ILL, Institut Nanosciences et Cryogénie (INAC), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Magnétisme et Diffusion Neutronique (MDN), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Magnétisme et Supraconductivité (NEEL - MagSup), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire national des champs magnétiques intenses - Toulouse ( LNCMI ), Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut Laue-Langevin ( ILL ), Institut Nanosciences et Cryogénie ( INAC ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Grenoble Alpes ( UGA ), Institut Néel ( NEEL ), Université Grenoble Alpes [Saint Martin d'Hères]-Centre National de la Recherche Scientifique ( CNRS ), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Grenoble Alpes (UGA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
Subjects: Horizontal field, Materials science, Physics - Instrumentation and Detectors, Neutron diffraction, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, 7. Clean energy, Condensed Matter - Strongly Correlated Electrons, Optics, 0103 physical sciences, [ PHYS.PHYS.PHYS-GEN-PH ] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Instrumentation, [ PHYS.PHYS.PHYS-INS-DET ] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Spectrometer, Strongly Correlated Electrons (cond-mat.str-el), business.industry, Instrumentation and Detectors (physics.ins-det), 021001 nanoscience & nanotechnology, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Magnetic field, Duty cycle, Rise time, Magnet, 0210 nano-technology, business, Single crystal
Abstract: We present the first long-duration and high duty cycle 40-tesla pulsed-field cryomagnet addressed to single crystal neutron diffraction experiments at temperatures down to 2 K. The magnet produces a horizontal field in a bi-conical geometry, $\pm$15 and $\pm$30{\deg} upstream and downstream of the sample, respectively. Using a 1.15MJ mobile generator, magnetic field pulses of 100 ms length are generated in the magnet, with a rise time of 23 ms and a repetition rate of 6-7 pulses per hour at 40 T. The setup was validated for neutron diffraction on the CEA-CRG three-axis spectrometer IN22 at the ILL., Comment: 7 pages, 8 figures
Published: 2018

23. Design and Tests of the 100-T Triple Coil at LNCMI

Author: P. Frings, J. Béard, Florence Lecouturier, J. Billette, Nelson Ferreira, Jean-Pierre Nicolin, Jean-Marc Lagarrigue, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Field (physics), Instrumentation, 02 engineering and technology, Superconducting magnet, 01 natural sciences, 7. Clean energy, law.invention, symbols.namesake, law, 0103 physical sciences, Electrical and Electronic Engineering, Aerospace engineering, 010306 general physics, ComputingMilieux_MISCELLANEOUS, Physics, Electromagnet, business.industry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Magnetic field, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Electromagnetic coil, Magnet, symbols, 0210 nano-technology, business, Lorentz force
Abstract: The Laboratoire National des Champs Magnetiques Intenses (LNCMI) is a French host facility for experiments in high magnetic fields. Based on two sites, the LNCMI offers routinely static magnetic fields up to 36 T at its Grenoble site, and pulsed magnetic fields up to 90 T using nondestructive magnets and up to 180 T using single-turn magnets at its Toulouse site. Internal research is carried out in the lab and experiment time is allocated to external researchers. LNCMI is a founding member of the European Magnetic Field Laboratory with the Hochfeld-Magnetlabor in Dresden (HLD) and High Field Magnet Laboratory in Nijmegen. The LNCMI develops all the instrumentation required by experiments in high magnetic fields, in particular, the electromagnets that generates these high fields. The main difficulty in generating a very high magnetic field in a nondestructive way is to contain the huge stresses on the magnet conductors due to the Lorentz forces. We present here the design and first operation of a new type of pulsed magnet consisting of three nested coils energized with three independent capacitor banks. This triple coil, unique in the world and associated with the most powerful generators of the LNCMI, reached a peak field value of 98.8 T and permitted the LNCMI to break the European record for the nondestructive pulsed magnetic fields established at 95.6 T in October 2016 by HLD. The next objective is to go beyond the symbolic value of 100 T and the world record of 100.75 T held by the Los Alamos National Laboratory since June 2012. We will describe the next steps toward this goal and some ways to go beyond, keeping in mind that this magnet is above all else a tool for scientific research, in particular to explore the fundamental properties of the matter.
Published: 2018

24. The DNA of Leadership : Creating Healthy Leaders and Vibrant Organizations

Author: Myron J. Beard, Alan Weiss, Myron J. Beard, and Alan Weiss
Subjects: Leadership
Abstract: Much like DNA provides the structure and design for life, The DNA of Leadership defines the behaviors that are essential to become an outstanding leader. This book is the result of working with thousands of executives, reviewing their behaviors, and identifying characteristics that are required for high levels of success, including: Setting a forceful vision; Identifying and hiring extraordinary talent; Delegating for leveraging of results; Communicating for impact; Having difficult conversations; Creating a compelling business model. This book is written is for leaders at every level in an organization, from the first-time manager to the chief executive officer and offers practical ways to change your behavior and provides an active roadmap toward becoming a truly outstanding leader.
Published: 2017

25. Detailed characterization of laser-produced astrophysically-relevant jets formed via a poloidal magnetic nozzle

Author: A. A. Soloviev, K. Naughton, Benjamin Khiar, Drew Higginson, R. Riquier, E. D. Filippov, Oliver Portugall, Caterina Riconda, G. Revet, S. A. Pikuz, Tommaso Vinci, S. N. Ryazantsev, I. Yu. Skobelev, D. Khaghani, M. Blecher, H. Pépin, Oswald Willi, Marco Borghesi, J. Béard, K. F. Burdonov, M. V. Starodubtsev, Julien Fuchs, S. N. Chen, Andrea Ciardi, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Queen's University [Belfast] (QUB), Énergie Matériaux Télécommunications - INRS (EMT-INRS), Institut National de la Recherche Scientifique [Québec] (INRS)-Université du Québec à Montréal = University of Québec in Montréal (UQAM), Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Don State Technical University, Institute of Applied Physics (IAP, Nizhny Novgorod), Dipartimento di Fisica 'Giuseppe Occhialini' = Department of Physics 'Giuseppe Occhialini' [Milano-Bicocca], Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB), Institut für Laser und Plasmaphysik, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and Università degli Studi di Milano-Bicocca [Milano] (UNIMIB)
Subjects: Astrophysical plasmas, Nuclear and High Energy Physics, Tokamak, Atmospheric-pressure plasma, Outflows, 01 natural sciences, 010305 fluids & plasmas, law.invention, Magnetohydrodynamics, law, Physics::Plasma Physics, 0103 physical sciences, Jets, Magnetic pressure, 010306 general physics, Magnetosphere particle motion, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], Jet (fluid), Radiation, Plasma, Magnetic field, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Laser-plasma interactions
Abstract: The collimation of astrophysically-relevant plasma ejecta in the form of narrow jets via a poloidal magnetic field is studied experimentally by irradiating a target situated in a 20 T axial magnetic field with a 40 J, 0.6 ns, 0.7 mm diameter, high-power laser. The dynamics of the plasma shaping by the magnetic field are studied over 70 ns and up to 20 mm from the source by diagnosing the electron density, temperature and optical self-emission. These show that the initial expansion of the plasma is highly magnetized, which leads to the formation of a cavity structure when the kinetic plasma pressure compresses the magnetic field, resulting in an oblique shock [A. Ciardi et al., Phys. Rev. Lett. 110, 025002 (2013)]. The resulting poloidal magnetic nozzle collimates the plasma into a narrow jet [B. Albertazzi et al., Science 346, 325 (2014)]. At distances far from the target, the jet is only marginally magnetized and maintains a high aspect ratio due to its high Mach-number (M∼20) and not due to external magnetic pressure. The formation of the jet is evaluated over a range of laser intensities (1012–1013 W/cm2), target materials and orientations of the magnetic field. Plasma cavity formation is observed in all cases and the viability of long-range jet formation is found to be dependent on the orientation of the magnetic field.
Published: 2017

26. Pulsed high magnetic field measurement via a Rubidium vapor sensor

Author: Donatella Ciampini, Ennio Arimondo, Stefano Scotto, Nicolas Bruyant, Carlo Rizzo, J. Béard, Sylvie George, Remy Battesti, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Dipartimento di fisica dell'Università di Pisa, University of Pisa - Università di Pisa, Rizzo, Carlo, Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Grenoble Alpes (UGA), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Toulouse ( LNCMI ), Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: [PHYS.PHYS.PHYS-OPTICS] Physics [physics]/Physics [physics]/Optics [physics.optics], high magnetic field, pulsed magnetic field, Rubidium vapor sensor, Physics - Instrumentation and Detectors, Field (physics), Atomic Physics (physics.atom-ph), chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, 010305 fluids & plasmas, law.invention, Rubidium, Physics - Atomic Physics, Cross section (physics), rubidium, Optics, law, magnetic field measurement, 0103 physical sciences, Perpendicular, [ PHYS.PHYS.PHYS-GEN-PH ] Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], [PHYS.PHYS.PHYS-ATOM-PH] Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 010306 general physics, [ PHYS.PHYS.PHYS-INS-DET ] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Instrumentation, ComputingMilieux_MISCELLANEOUS, Line (formation), Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], business.industry, Instrumentation and Detectors (physics.ins-det), Laser, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Magnetic field, Metrology, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], gas sensors, chemistry, [PHYS.PHYS.PHYS-INS-DET] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], fluorescence, Atomic physics, business
Abstract: We present a new technique to measure pulsed magnetic fields based on the use of Rubidium in gas phase as a metrological standard. We have therefore developed an instrument based on laser inducing transitions at about 780~nm (D2 line) in a Rubidium gas contained in a mini-cell of 3~mm~x~3~mm cross section. To be able to insert such a cell in a standard high field pulsed magnet we have realized a fibred probe kept at a fixed temperature. Transition frequencies for both the $\pi$ (light polarization parallel to the magnetic field) and $\sigma$ (light polarization perpendicular to the magnetic field) configurations are measured by a commercial wavemeter. One innovation of our sensor is that in addition of monitoring the light transmitted by the Rb cell, which is usual, we also monitor the fluorescence emission of the gas sample from a very small volume with the advantage of reducing the impact of the field inhomogeneity on the field measurement. Our sensor has been tested up to about 58~T., Comment: Submitted to Review Scientific Instruments
Published: 2017
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27. The French High Magnetic Field Facility

Author: François Debray and J. Béard
Subjects: Physics, Nuclear physics, General Materials Science, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, High magnetic field, Magnetic field
Abstract: The Laboratoire National des Champs Magnetiques Intenses (LNCMI) is a host laboratory for experiments in high magnetic fields. It was created on the 1st of January 2009 through the merger of the Laboratoire des Champs Magnetiques Intenses (Grenoble, specialized in DC fields) and the Laboratoire National des Champs Magnetiques Pulses (Toulouse, specialized in pulsed fields). The facility is open to a large community of users from all over Europe and the rest of the world. In this paper we report our efforts to offer the highest magnetic fields, ranging from 35 T DC, through 80 T non-destructive, up to 170 T semi-destructive, in the best conditions for our in-house and visiting scientists. We describe the installations and coils improvements. As an example of our activity we present some recent scientific results.
Published: 2012

28. Special Coils Development at the National High Magnetic Field Laboratory in Toulouse

Author: P. Frings, J. Béard, M. Suleiman, Florence Lecouturier, J. Billette, Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Diffraction, Physics, Quantitative Biology::Biomolecules, business.industry, Physics::Medical Physics, Solenoid, Plasma, Conical surface, Neutron scattering, Condensed Matter Physics, 7. Clean energy, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Nuclear magnetic resonance, Optics, Optical path, Electromagnetic coil, Magnet, 0103 physical sciences, General Materials Science, 010306 general physics, business, ComputingMilieux_MISCELLANEOUS
Abstract: The Laboratoire National des Champs Magnetiques Intenses (LNCMI) develops different types of coils suited to specific experiments. We present some recent developments on magnet design. Several coils are dedicated to experiments in large scale facilities in France and Switzerland. A 30 T split-pair coil for X-rays diffraction and one 40 T coil for plasma physics at the LULI, two 30 T coils with axial access (one with an conical bore) for X-ray diffraction and absorption experiments. A 40 T wide angle conical access solenoid with a high duty-cycle for neutron scattering at the ILL is being constructed. For use at the installation in Toulouse we have developed, apart from our standard 60 and 70 T coils, several special coils: a coil with a long optical path with 30 T transverse magnetic field and a 90 T long pulse dual coil system.
Published: 2012

29. Dichotomy between the Hole and Electron Behavior in Multiband Superconductor FeSe Probed by Ultrahigh Magnetic Fields

Author: Takuya Yamashita, J. Béard, Hilbert von Löhneysen, Alix McCollam, Marc Nardone, Shigeru Kasahara, Takasada Shibauchi, Amalia I. Coldea, S. F. Blake, William Knafo, Amir A. Haghighirad, Yuji Matsuda, Frédéric Hardy, Arjun Narayanan, Andrew J. Schofield, Matthew D. Watson, T. Wolf, Christoph Meingast, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Physics, Superconductivity, Condensed matter physics, General Physics and Astronomy, Quantum oscillations, Fermi surface, 02 engineering and technology, Electron, Electronic structure, Correlated Electron Systems / High Field Magnet Laboratory (HFML), 021001 nanoscience & nanotechnology, 01 natural sciences, Magnetic field, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Hall effect, Electrical resistivity and conductivity, 0103 physical sciences, 010306 general physics, 0210 nano-technology, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), ComputingMilieux_MISCELLANEOUS
Abstract: Magnetoresistivity ${\ensuremath{\rho}}_{xx}$ and Hall resistivity ${\ensuremath{\rho}}_{xy}$ in ultrahigh magnetic fields up to 88 T are measured down to 0.15 K to clarify the multiband electronic structure in high-quality single crystals of superconducting FeSe. At low temperatures and high fields we observe quantum oscillations in both resistivity and the Hall effect, confirming the multiband Fermi surface with small volumes. We propose a novel approach to identify from magnetotransport measurements the sign of the charge carriers corresponding to a particular cyclotron orbit in a compensated metal. The observed significant differences in the relative amplitudes of the quantum oscillations between the ${\ensuremath{\rho}}_{xx}$ and ${\ensuremath{\rho}}_{xy}$ components, together with the positive sign of the high-field ${\ensuremath{\rho}}_{xy}$, reveal that the largest pocket should correspond to the hole band. The low-field magnetotransport data in the normal state suggest that, in addition to one hole and one almost compensated electron band, the orthorhombic phase of FeSe exhibits an additional tiny electron pocket with a high mobility.
Published: 2015

30. Fermi surface in the hidden-order state ofURu2Si2under intense pulsed magnetic fields up to 81 T

Author: P. Frings, Cyril Jaudet, G. W. Scheerer, M. Suleiman, Tatsuma D. Matsuda, Daisuke Aoki, G. Knebel, J. Barata, Alain Audouard, Loïc Drigo, J. Billette, J. Béard, Jacques Flouquet, Alexandre Pourret, Marc Nardone, William Knafo, and A. Zitouni
Subjects: Physics, Phase transition, Residual resistivity, Magnetic anisotropy, Effective mass (solid-state physics), Condensed matter physics, Electrical resistivity and conductivity, Quantum oscillations, Fermi surface, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Phase diagram
Abstract: We present measurements of the resistivity ${\ensuremath{\rho}}_{x,x}$ of ${\mathrm{URu}}_{2}{\mathrm{Si}}_{2}$ high-quality single crystals in pulsed high magnetic fields up to 81 T at a temperature of 1.4 K and up to 60 T at temperatures down to 100 mK. For a field H applied along the magnetic easy axis c, a strong sample dependence of the low-temperature resistivity in the hidden-order phase is attributed to a high carrier mobility. The interplay between the magnetic and orbital properties is emphasized by the angle dependence of the phase diagram, where magnetic transition fields and crossover fields related to the Fermi surface properties follow a 1/$cos\ensuremath{\theta}$ law, $\ensuremath{\theta}$ being the angle between H and c. For $\mathbf{H}\ensuremath{\parallel}\mathbf{c}$, a crossover defined at a kink of ${\ensuremath{\rho}}_{x,x}$, as initially reported in [Shishido, Phys. Rev. Lett. 102, 156403 (2009)], is found to be strongly sample dependent: its characteristic field ${\ensuremath{\mu}}_{0}{H}^{*}$ varies from $\ensuremath{\simeq}$20 T in our best sample with a residual resistivity ratio $\mathrm{RRR}=$ ${\ensuremath{\rho}}_{x,x}(300\phantom{\rule{0.16em}{0ex}}\mathrm{K})/$ ${\ensuremath{\rho}}_{x,x}(2\phantom{\rule{0.16em}{0ex}}\mathrm{K})$ of 225 to $\ensuremath{\simeq}$25 T in a sample with a RRR of 90. A second crossover is defined at the maximum of ${\ensuremath{\rho}}_{x,x}$ at the sample-independent low-temperature (LT) characteristic field ${\ensuremath{\mu}}_{0}{H}_{\ensuremath{\rho},\mathrm{max}}^{\mathrm{LT}}\ensuremath{\simeq}30$ T. Fourier analyses of Shubnikov-de Haas oscillations show that ${H}_{\ensuremath{\rho},\mathrm{max}}^{\mathrm{LT}}$ coincides with a sudden modification of the Fermi surface, while ${H}^{*}$ lies in a regime where the Fermi surface is smoothly modified. For $\mathbf{H}\ensuremath{\parallel}\mathbf{a}$, (i) no phase transition is observed at low temperature and the system remains in the hidden-order phase up to 81 T, (ii) quantum oscillations surviving up to 7 K are related to a new orbit observed at the frequency ${F}_{\ensuremath{\lambda}}\ensuremath{\simeq}1350$ T and associated with a low effective mass ${m}_{\ensuremath{\lambda}}^{*}=(1\ifmmode\pm\else\textpm\fi{}0.5){m}_{0}$, where ${m}_{0}$ is the free electron mass, and (iii) no Fermi surface modification occurs up to 81 T.
Published: 2014

31. A 31T split-pair pulsed magnet for single crystal x-ray diffraction at low temperature

Author: Fabienne Duc, J. Béard, Lin Zhang, Carsten Detlefs, Thomas Roth, G. L. J. A. Rikken, Marc Nardone, A. Zitouni, X. Fabrèges, J.-P. Nicolin, M. Lesourd, P. Delescluse, J. Billette, P. Frings, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), European XFEL GmbH (XFEL), European XFEL GmbH, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay
Subjects: Cryostat, Diffraction, Physics - Instrumentation and Detectors, Materials science, FOS: Physical sciences, 02 engineering and technology, 7. Clean energy, 01 natural sciences, law.invention, Condensed Matter - Strongly Correlated Electrons, Optics, law, 0103 physical sciences, ddc:530, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Instrumentation, Strongly Correlated Electrons (cond-mat.str-el), business.industry, Particle accelerator, Instrumentation and Detectors (physics.ins-det), 021001 nanoscience & nanotechnology, Synchrotron, Beamline, Magnet, X-ray crystallography, Xray single crystal diffraction- High pulsed field- split pair magnet-Low temperature, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], 0210 nano-technology, business, Single crystal
Abstract: We have developed a pulsed magnet system with panoramic access for synchrotron x-ray diffraction in magnetic fields up to 31T and at low temperature down to 1.5 K. The apparatus consists of a split-pair magnet, a liquid nitrogen bath to cool the pulsed coil, and a helium cryostat allowing sample temperatures from 1.5 up to 250 K. Using a 1.15MJ mobile generator, magnetic field pulses of 60 ms length were generated in the magnet, with a rise time of 16.5 ms and a repetition rate of 2 pulses/hour at 31 T. The setup was validated for single crystal diffraction on the ESRF beamline ID06.
Published: 2014

32. Laboratory formation of a scaled protostellar jet by coaligned poloidal magnetic field

Author: Hans-Peter Schlenvoigt, G. Revet, Marco Borghesi, Martín Huarte-Espinosa, I. Yu. Skobelev, Henri Pépin, K. Naughton, Motoaki Nakatsutsumi, O. Portugall, Andrea Ciardi, J. Béard, T. Herrmannsdörfer, Zakary Burkley, Thomas E. Cowan, Julien Fuchs, S. A. Pikuz, Florian Kroll, Tommaso Vinci, R. Riquier, A. Ya. Faenov, A. A. Soloviev, Rosaria Bonito, Caterina Riconda, L. Romagnani, Adam Frank, Drew Higginson, J. Billette, Bruno Albertazzi, Sophia Chen, Laboratoire pour l'utilisation des lasers intenses (LULI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Albertazzi, B., Ciardi, A., Nakatsutsumi, M., Vinci, T., Béard, J., Bonito, R., Billette, J., Borghesi, M., Burkley, Z., Chen, S. N., Cowan, T. E., Herrmannsdörfer, T., Higginson, D. P., Kroll, F., Pikuz, S. A., Naughton, K., Romagnani, L., Riconda, C., Revet, G., Riquier, R., Schlenvoigt, H.-P., Skobelev, I. Yu., Faenov, A. Ya., Soloviev, A., Huarte-Espinosa, M., Frank, A., Portugall, O., Pépin, H., Fuchs, J., École normale supérieure - Paris (ENS Paris), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
Subjects: jets, Physics, Jet (fluid), Multidisciplinary, Shock (fluid dynamics), Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, Flow (psychology), Plasma, Conical surface, Astrophysics, 01 natural sciences, SIMULATIONS, 010305 fluids & plasmas, Magnetic field, COLLIMATION, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], DISCOVERY, 0103 physical sciences, DG-TAURI, 010303 astronomy & astrophysics, ACCRETION DISCS, Astrophysics::Galaxy Astrophysics, DRIVEN JETS
Abstract: International audience; Although bipolar jets are seen emerging from a wide variety of astrophysical systems, the issue of their formation and morphology beyond their launching is still under study. Our scaled laboratory experiments, representative of young stellar object outflows, reveal that stable and narrow collimation of the entire flow can result from the presence of a poloidal magnetic field whose strength is consistent with observations. The laboratory plasma becomes focused with an interior cavity. This gives rise to a standing conical shock from which the jet emerges. Following simulations of the process at the full astrophysical scale, we conclude that it can also explain recently discovered x-ray emission features observed in low-density regions at the base of protostellar jets, such as the well-studied jet HH 154.
Published: 2014

33. Diagnostics of laser-produced plasmas based on the analysis of intensity ratios of He-like ions X-ray emission

Author: S. A. Pikuz, J. Béard, Julien Fuchs, O. Portugall, I. Yu. Skobelev, Tatiana Pikuz, A. Ya. Faenov, Alexei N. Grum-Grzhimailo, G. Revet, Drew Higginson, S. N. Ryazantsev, A. A. Soloviev, and Sophia Chen
Subjects: Physics, Electron density, Context (language use), Electron, Plasma, Condensed Matter Physics, Laser, 01 natural sciences, Effective nuclear charge, 010305 fluids & plasmas, law.invention, Ion, Physics::Plasma Physics, law, 0103 physical sciences, Plasma diagnostics, Atomic physics, 010306 general physics
Abstract: In this paper, we detail the diagnostic technique used to infer the spatially resolved electron temperatures and densities in experiments dedicated to investigate the generation of magnetically collimated plasma jets. It is shown that the relative intensities of the resonance transitions in emitting He-like ions can be used to measure the temperature in such recombining plasmas. The intensities of these transitions are sensitive to the plasma density in the range of 1016–1020 cm−3 and to plasma temperature ranges from 10 to 100 eV for ions with a nuclear charge Zn ∼ 10. We show how detailed calculations of the emissivity of F VIII ions allow to determine the parameters of the plasma jets that were created using ELFIE ns laser facility (Ecole Polytechnique, France). The diagnostic and analysis technique detailed here can be applied in a broader context than the one of this study, i.e., to diagnose any recombining plasma containing He-like fluorine ions.
Published: 2016

34. Universal quantum oscillations in the underdoped cuprate superconductors

Author: Cyril Proust, Neven Barišić, Guichuan Yu, Wojciech Tabis, Chelsey Dorow, Sven Badoux, Mun Chan, J. Béard, Martin Greven, X. Zhao, Baptiste Vignolle, Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), School of Physics and Astronomy [Minneapolis], University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Centre for Epigenetics, University of Capenhagen, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)
Subjects: FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, 01 natural sciences, Superconductivity (cond-mat.supr-con), Tetragonal crystal system, Quantum mechanics, Condensed Matter::Superconductivity, 0103 physical sciences, Cuprate, 010306 general physics, quantum oscillations, underdoped cuprate superconductors, ComputingMilieux_MISCELLANEOUS, Physics, Superconductivity, Condensed matter physics, Condensed Matter - Superconductivity, Quantum oscillations, Fermi surface, 021001 nanoscience & nanotechnology, Magnetic field, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Quasiparticle, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, Pseudogap
Abstract: The metallic state of the underdoped high-Tc cuprates has remained an enigma: How may seemingly disconnected Fermi surface segments, observed in zero magnetic field as a result of the opening of a partial gap (the pseudogap), possess conventional quasiparticle properties? How do the small Fermi-surface pockets evidenced by the observation of quantum oscillations (QO) emerge as superconductivity is suppressed in high magnetic fields? Such QO, discovered in underdoped YBa2Cu3O6.5 (Y123) and YBa2Cu4O8 (Y124), signify the existence of a conventional Fermi surface (FS). However, due to the complexity of the crystal structures of Y123 and Y124 (CuO2 double-layers, CuO chains, low structural symmetry), it has remained unclear if the QO are specific to this particular family of cuprates. Numerous theoretical proposals have been put forward to explain the route toward QO, including materials-specific scenarios involving CuO chains and scenarios involving the quintessential CuO2 planes. Here we report the observation of QO in underdoped HgBa2CuO4+{\delta} (Hg1201), a model cuprate superconductor with individual CuO2 layers, high tetragonal symmetry, and no CuO chains. This observation proves that QO are a universal property of the underdoped CuO2 planes, and it opens the door to quantitative future studies of the metallic state and of the Fermi-surface reconstruction phenomenon in this structurally simplest cuprate., Comment: 17 pages, 5 figures
Published: 2013

35. Production of large volume, strongly magnetized laser-produced plasmas by use of pulsed external magnetic fields

Author: E. Veuillot, Olivier Portugall, Sophia Chen, S. Dittrich, Julien Fuchs, S. Nitsche, H. Pépin, Thomas E. Cowan, D. Da Silva, J. Béard, J. Albrecht, J. Billette, Thomas Herrmannsdörfer, S. Simond, Florian Kroll, Motoaki Nakatsutsumi, Tommaso Vinci, B. Hirardin, L. Romagnagni, Andrea Ciardi, Hans-Peter Schlenvoigt, T. Burris-Mog, Bruno Albertazzi, Caterina Riconda, Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire pour l'utilisation des lasers intenses (LULI), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Physics Department, MS-220 (UNR), University of Nevada [Reno], Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and École normale supérieure - Paris (ENS-PSL)
Subjects: Physics, Waves in plasmas, Plasma, Laser, 7. Clean energy, 01 natural sciences, Collimated light, 010305 fluids & plasmas, law.invention, Magnetic field, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Coupling (physics), law, Electromagnetic coil, 0103 physical sciences, Atomic physics, 010306 general physics, Instrumentation, Inertial confinement fusion
Abstract: International audience; The production of strongly magnetized laser plasmas, of interest for laboratory astrophysics and inertial confinement fusion studies, is presented. This is achieved by coupling a 16 kV pulse-power system. This is achieved by coupling a 16 kV pulse-power system, which generates a magnetic field by means of a split coil, with the ELFIE laser facility at Ecole Polytechnique. In order to influence the plasma dynamics in a significant manner, the system can generate, repetitively and without debris, high amplitude magnetic fields (40 T) in a manner compatible with a high-energy laser environment. A description of the system and preliminary results demonstrating the possibility to magnetically collimate plasma jets are given.
Published: 2013

36. High frequency magnetic oscillations of the organic metal $\theta$-(ET)$_4$ZnBr$_4$(C$_6$H$_4$Cl$_2$) in pulsed magnetic field of up to 81 T

Author: Fabienne Duc, J. Béard, G. L. J. A. Rikken, Marc Nardone, Elena I. Zhilyaeva, William Knafo, B. Griffe, Rimma N. Lyubovskaya, Alain Audouard, J. Billette, Nicolas Bruyant, J.-P. Nicolin, P. Frings, F. Giquel, Rustem B. Lyubovskii, Gennadii V. Shilov, G. W. Scheerer, P. Delescluse, J.-M. Lagarrigue, M. Suleiman, A. Zitouni, and David Vignolles
Subjects: 02 engineering and technology, 01 natural sciences, Metal, symbols.namesake, Condensed Matter - Strongly Correlated Electrons, Chain (algebraic topology), 0103 physical sciences, 010306 general physics, Linear combination, Instrumentation, Condensed matter physics, Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 3. Good health, Electronic, Optical and Magnetic Materials, Magnetic field, Pulse (physics), Amplitude, Fourier transform, visual_art, Orbit (dynamics), visual_art.visual_art_medium, symbols, Atomic physics, 0210 nano-technology
Abstract: De Haas-van Alphen oscillations of the organic metal $\theta$-(ET)$_4$ZnBr$_4$(C$_6$H$_4$Cl$_2$) are studied in pulsed magnetic fields up to 81 T. The long decay time of the pulse allows determining reliable field-dependent amplitudes of Fourier components with frequencies up to several kiloteslas. The Fourier spectrum is in agreement with the model of a linear chain of coupled orbits. In this model, all the observed frequencies are linear combinations of the frequency linked to the basic orbit $\alpha$ and to the magnetic-breakdown orbit $\beta$., Comment: 6 pages, 4 figures
Published: 2012

37. Optimization of large multiple coil systems for pulsed magnets

Author: P. Frings, Sergei Zherlitsyn, Jos A. A. J. Perenboom, Bhavtosh Bansal, J. Béard, Tao Peng, Fritz Herlach, Institute for Molecules and Materials [Nijmegen], Radboud university [Nijmegen], Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Inverse problems in earth monitoring (ARIANA), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Signal, Images et Systèmes (Laboratoire I3S - SIS), Laboratoire d'Informatique, Signaux, et Systèmes de Sophia Antipolis (I3S), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Laboratoire d'Informatique, Signaux, et Systèmes de Sophia Antipolis (I3S), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), Laboratoire Franco-Chinois d'Informatique, d'Automatique et de Mathématiques Appliquées (LIAMA), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Chinese Academy of Sciences [Changchun Branch] (CAS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institute of Automation - Chinese Academy of Sciences-Centre National de la Recherche Scientifique (CNRS), Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Informatique, Signaux, et Systèmes de Sophia Antipolis (I3S), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Radboud University [Nijmegen], Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Grenoble Alpes (UGA)
Subjects: Computer science, Correlated Electron Systems / High Field Magnet Laboratory (HFML), 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, law.invention, Generator (circuit theory), Nuclear magnetic resonance, Materials Science(all), law, 0103 physical sciences, General Materials Science, 010306 general physics, ComputingMilieux_MISCELLANEOUS, business.industry, Pulse generator, Electrical engineering, Pulse duration, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Capacitor, Electromagnetic coil, Magnet, Software design, business, Excitation
Abstract: The generation of pulsed magnetic fields is limited by the Lorentz force on the conductor and by ohmic heating. A large coil can give higher field (and/or longer pulse duration), but for a single coil this may require high power that cannot be supplied by a feasible source. Power can be kept within acceptable limits by using a system of multiple coils. Pulsed field coils can be energized either by a pulsed power supply or a pulsed energy source. The energy or power supplies tend to be the most expensive part of the installation and a combination of high power and high energy is extremely expensive. In a multi-coil system , the increased design freedom allows to optimize the strength, pulse duration and heating of the coil, and to optimize the selection of materials and power supplies; one can so also minimize damage in case of coil failure. Because of the increased number of parameters, systematic insight into their mutual dependence is helpful in order to converge to an optimized design. Since the local optima are relatively weak, for the final design any standard method of pulsed coil design can be used. In this paper we will discuss strategies to determine the optimum choice for the design of inner- and outer-coil and how to optimize their design in relation to the supply type used. In particular, we will consider energy-limited capacitor banks and power-limited supplies. The approach will use scaling arguments and modeling tools as the PMDS package originally developed in Leuven. Optimization of coil systems is demonstrated with practical examples, such as the successful 87 T pulsed dual coil system in Dresden, and the design of the future ARMS successor in Toulouse
Published: 2010

38. Rapid cooling methods for pulsed magnets

Author: H. Jones, P. Frings, T. Hermannsdoerfer, Holger Witte, and J. Béard
Subjects: Materials science, Field (physics), Thermal resistance, Nuclear engineering, Superconducting magnet, Cryogenics, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Magnetic field, Nuclear magnetic resonance, Electromagnetic coil, Magnet, Water cooling, Electrical and Electronic Engineering
Abstract: Pulsed magnets are generally evaluated and compared in terms of the magnetic field they can achieve in combination with a bore size. However, in practice another criterion is equally important: the waiting time for a researcher in between two consecutive shots. The cooling time of pulsed magnets can range from a few minutes up to several hours, depending on coil size and desired field. Using simulations and measurements several options to reduce the cool down time are compared in this paper. One of the discussed methods is now routinely in use at the Laboratoire National des Champs Magnetiques Pulses (LNCMP) in Toulouse.
Published: 2008

39. Crystal structure, Fermi surface calculations and Shubnikov-de Haas oscillations spectrum of the organic metal $\theta$-(BETS)$_4$HgBr$_4$(C$_6$H$_5$Cl) at low temperature

Author: S. I. Pesotskii, Enric Canadell, J. Béard, David Vignolles, Rimma N. Lyubovskaya, Alain Audouard, Elena I. Zhilayeva, Rustem B. Lyubovskii, O. A. Bogdanova, Gena V. Shilov, Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Institute of Problems of Chemical Physics (IPCP), Russian Academy of Sciences [Moscow] (RAS), Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
Subjects: Phase transition, Condensed matter physics, Chemistry, Oscillation, Transition temperature, Fermi surface, 02 engineering and technology, General Chemistry, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Shubnikov–de Haas effect, Condensed Matter - Strongly Correlated Electrons, organic conductors, shubnikov-de Haas oscillations, 0103 physical sciences, General Materials Science, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], 010306 general physics, 0210 nano-technology, Electronic band structure, Monoclinic crystal system
Abstract: The organic metal \theta$-(BETS)$_4$HgBr$_4$(C$_6$H$_5$Cl) is known to undergo a phase transition as the temperature is lowered down to about 240 K. X-ray data obtained at 200 K indicate a corresponding modification of the crystal structure, the symmetry of which is lowered from quadratic to monoclinic. In addition, two different types of cation layers are observed in the unit cell. The Fermi surface (FS), which can be regarded as a network of compensated electron and hole orbits according to band structure calculations at room temperature, turns to a set of two alternating linear chains of orbits at low temperature. The field and temperature dependence of the Shubnikov-de Haas oscillations spectrum have been studied up to 54 T. Eight frequencies are observed which, in any case, points to a FS much more complex than predicted by band structure calculations at room temperature, even though some of the observed Fourier components might be ascribed to magnetic breakdown or frequency mixing. The obtained spectrum could result from either an interaction between the FS's linked to each of the two cation layers or to an eventual additional phase transition in the temperature range below 200 K., Comment: accepted for publication in Solid State Sciences
Published: 2007

40. Frequency combinations in the magnetoresistance oscillations spectrum of a linear chain of coupled orbits with a high scattering rate

Author: Enric Canadell, J. Béard, Alain Audouard, Eduard B. Yagubskii, Vladimir Laukhin, David Vignolles, N. G. Spitsina, Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Problems of Chemical Physics (IPCP), Russian Academy of Sciences [Moscow] (RAS), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institució Catalana de Recerca i Estudis Avançats (ICREA), cooperation agreement CNRS-CSIC, and Euromagnet contract
Subjects: Physics, Magnetoresistance, Condensed matter physics, Strongly Correlated Electrons (cond-mat.str-el), Oscillation, Spectrum (functional analysis), Semiclassical physics, FOS: Physical sciences, Fermi surface, 02 engineering and technology, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Condensed Matter - Strongly Correlated Electrons, Chain (algebraic topology), Scattering rate, 0103 physical sciences, 71.18.+y, 71.20.Rv, 72.20.My, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], 010306 general physics, 0210 nano-technology
Abstract: The oscillatory magnetoresistance spectrum of the organic metal (BEDO)$_5$Ni(CN)$_4\cdot$3C$_2$H$_4$(OH)$_2$ has been studied up to 50 T, in the temperature range from 1.5 K to 4.2 K. In high magnetic field, its Fermi surface corresponds to a linear chain of quasi-two-dimensional orbits coupled by magnetic breakdown (MB). The scattering rate consistently deduced from the data relevant to the basic $\alpha$ and the MB-induced $\beta$ orbits is very large which points to a significant reduction of the chemical potential oscillation. Despite of this feature, the oscillations spectrum exhibits many frequency combinations. Their effective masses and (or) Dingle temperature are not in agreement with either the predictions of the quantum interference model or the semiclassical model of Falicov and Stachowiak., Comment: to be published in Eur. Phys. J. B (2007)
Published: 2007
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41. Pressure dependence of Shubnikov–de Haas oscillation spectra in the quasi-two-dimensional organic metalβ″(BEDT−TTF)4(NH4)[Fe(C2O4)3]∙DMF

Author: Vladimir Laukhin, Alain Audouard, David Vignolles, Eduard B. Yagubskii, Tatyana G. Prokhorova, Enric Canadell, J. Béard, and Marc Nardone
Subjects: Physics, Condensed matter physics, Magnetoresistance, Oscillation, Fermi surface, Condensed Matter Physics, Spectral line, Electronic, Optical and Magnetic Materials, Magnetic field, Crystallography, Condensed Matter::Superconductivity, Scattering rate, Molecule, Condensed Matter::Strongly Correlated Electrons, Ambient pressure
Abstract: The pressure dependence of the interlayer magnetoresistance of the quasi-two dimensional organic metal ${\ensuremath{\beta}}^{\ensuremath{''}}{\ensuremath{-}(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{4}(\mathrm{N}{\mathrm{H}}_{4})[\mathrm{Fe}{({\mathrm{C}}_{2}{\mathrm{O}}_{4})}_{3}]∙\mathrm{DMF}$ [where BEDT-TTF represents bis(ethylenedithio)tetrathiofulvalene and DMF is dimethylformamide] has been investigated up to $1\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ in pulsed magnetic fields up to $55\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. The Shubnikov\char21{}de Haas oscillation spectra can be interpreted on the basis of three compensated orbits in the whole pressure range studied, suggesting that the Fermi surface topology remains qualitatively the same as the applied pressure varies. In addition, all the observed frequencies, normalized to their value at ambient pressure, exhibit the same sizable pressure dependence. Despite this behavior, which is at variance with that of numerous charge-transfer salts based on the BEDT-TTF molecule, nonmonotonic pressure-induced variations of parameters such as the scattering rate linked to the various detected orbits are observed.
Published: 2006

42. Copper/Stainless Steel Polyhelix Magnets

Author: François Debray, J. M. Tudela, F. Lecouturier, P. Frings, G. L. J. A. Rikken, Nelson Ferreira, J. Billette, J. Béard, Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)
Subjects: Area fraction, Materials science, Electromagnet, Metallurgy, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Copper, Electronic, Optical and Magnetic Materials, Magnetomechanical effects, law.invention, Magnetic field, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], chemistry, law, Magnet, 0103 physical sciences, Electrical and Electronic Engineering, 010306 general physics, 0210 nano-technology, Electrical conductor, ComputingMilieux_MISCELLANEOUS, High magnetic field
Abstract: The LNCMI has been involved since many years in the research and development of copper/stainless steel (Cu/SS) macrocomposite conductors for wire wound pulsed field magnets, generating magnetic fields up to 80 Tesla. The mechanical and electrical properties are adjusted to the magnet requirements by selecting the area fraction of the stainless steel reinforcement and the work-hardening state at the end of the drawing procedure.
Published: 2012

43. Three phylogenetic groups have driven the recent population expansion of Cryptococcus neoformans

Author: P. M. Ashton, L. T. Thanh, P. H. Trieu, D. Van Anh, N. M. Trinh, J. Beardsley, F. Kibengo, W. Chierakul, D. A. B. Dance, S. Rattanavong, V. Davong, L. Q. Hung, N. V. V. Chau, N. L. N. Tung, A. K. Chan, G. E. Thwaites, D. G. Lalloo, C. Anscombe, L. T. H. Nhat, J. Perfect, G. Dougan, S. Baker, S. Harris, and J. N. Day
Subjects: Science
Abstract: Cryptococcus neoformans is an opportunistic fungal pathogen which primarily affects people with immune defects including those living with HIV. Here, the authors sequence and analyze genomes of 699 isolates, and identify recent population expansion driven by three phylogenetic groups.
Published: 2019
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44. Ocean acidification and nutrient limitation synergistically reduce growth and photosynthetic performances of a green tide alga Ulva linza

Author: G. Gao, J. Beardall, M. Bao, C. Wang, W. Ren, and J. Xu
Subjects: Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract: Large-scale green tides have been invading the coastal zones of the western Yellow Sea annually since 2008. Meanwhile, oceans are becoming more acidic due to continuous absorption of anthropogenic carbon dioxide, and intensive seaweed cultivation in Chinese coastal areas is leading to severe regional nutrient limitation. However, little is known about the combined effects of global and local stressors on the eco-physiology of bloom-forming algae. We cultured Ulva linza for 9–16 days under two levels of pCO2 (400 and 1000 µatm) and four treatments of nutrients (nutrient repletion, N limitation, P limitation, and N–P limitation) to investigate the physiological responses of this green tide alga to the combination of ocean acidification and nutrient limitation. For both sporelings and adult plants, elevated pCO2 did not affect the growth rate when cultured under nutrient-replete conditions but reduced it under P limitation; N or P limitations by themselves reduced growth rate. P limitation resulted in a larger inhibition in growth for sporelings compared to adult plants. Sporelings under P limitation did not reach the mature stage after 16 days of culture while those under P repletion became mature by day 11. Elevated pCO2 reduced net photosynthetic rate for all nutrient treatments but increased nitrate reductase activity and soluble protein content under P-replete conditions. N or P limitation reduced nitrate reductase activity and soluble protein content. These findings indicate that ocean acidification and nutrient limitation would synergistically reduce the growth of Ulva species and may thus hinder the occurrence of green tides in a future ocean environment.
Published: 2018
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45. Differential photosynthetic responses of marine planktonic and benthic diatoms to ultraviolet radiation under various temperature regimes

Author: Y. Wu, F. Yue, J. Xu, and J. Beardall
Subjects: Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract: We studied the photophysiological responses to ultraviolet radiation (UVR) of two diatoms, isolated from different environmental niches. Both species showed the highest sensitivity to UV radiation under relatively low temperature, while they were less inhibited under moderately increased temperature. Under the highest temperature applied in this study, the benthic diatom Nitzschia sp. showed minimal sensitivity to UV radiation, while inhibition of the planktonic species, Skeletonema sp., increased further compared with that at the growth temperature. These photochemical responses were linked to values for the repair and damage processes within the cell; higher damage rates and lower repair rates were observed for Skeletonema sp. under suboptimal temperature, while for Nitzschia sp., repair rates increased and damage rates were stable within the applied temperature range. Our results suggested that the response of the microalgae to UV radiation correlated with their niche environments, the periodic exposure to extreme temperatures promoting the resistance of the benthic species to the combination of high temperature and UV radiation.
Published: 2017
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46. Blooms of cyanobacteria in a temperate Australian lagoon system post and prior to European settlement

Author: P. L. M. Cook, M. Jennings, D. P. Holland, J. Beardall, C. Briles, A. Zawadzki, P. Doan, K. Mills, and P. Gell
Subjects: Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract: Blooms of noxious N2 fixing cyanobacteria such as Nodularia spumigena are a recurring problem in some estuaries; however, the historic occurrence of such blooms in unclear in many cases. Here we report the results of a palaeoecological study on a temperate Australian lagoon system (the Gippsland Lakes) where we used stable isotopes and pigment biomarkers in dated cores as proxies for eutrophication and blooms of cyanobacteria. Pigment proxies show a clear signal, with an increase in cyanobacterial pigments (echinenone, canthaxanthin and zeaxanthin) in the period coinciding with recent blooms. Another excursion in these proxies was observed prior to the opening of an artificial entrance to the lakes in 1889, which markedly increased the salinity of the Gippsland Lakes. A coincident increase in the sediment organic-carbon content in the period prior to the opening of the artificial entrance suggests that the bottom waters of the lakes were more stratified and hypoxic, which would have led to an increase in the recycling of phosphorus. After the opening of the artificial entrance, there was a ∼ 60-year period with low values for the cyanobacterial proxies as well as a low sediment organic-carbon content suggesting a period of low bloom activity associated with the increased salinity of the lakes. During the 1940s, the current period of re-eutrophication commenced, as indicated by a steadily increasing sediment organic-carbon content and cyanobacterial pigments. We suggest that increasing nitrogen inputs from the catchment led to the return of hypoxia and increased phosphorus release from the sediment, which drove the re-emergence of cyanobacterial blooms.
Published: 2016
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47. The quality and diagnostic value of open narratives in verbal autopsy: a mixed-methods analysis of partnered interviews from Malawi

Author: C. King, C. Zamawe, M. Banda, N. Bar-Zeev, J. Beard, J. Bird, A. Costello, P. Kazembe, D. Osrin, E. Fottrell, and for the VacSurv Consortium
Subjects: Verbal autopsy, Open narrative, Closed questions, Bias, Sub-Saharan Africa, Medicine (General), R5-920
Abstract: Abstract Background Verbal autopsy (VA), the process of interviewing a deceased’s family or caregiver about signs and symptoms leading up to death, employs tools that ask a series of closed questions and can include an open narrative where respondents give an unprompted account of events preceding death. The extent to which an individual interviewer, who generally does not interpret the data, affects the quality of this data, and therefore the assigned cause of death, is poorly documented. We aimed to examine inter-interviewer reliability of open narrative and closed question data gathered during VA interviews. Methods During the introduction of VA data collection, as part of a larger study in Mchinji district, Malawi, we conducted partner interviews whereby two interviewers independently recorded open narrative and closed questions during the same interview. Closed questions were collected using a smartphone application (mobile-InterVA) and open narratives using pen and paper. We used mixed methods of analysis to evaluate the differences between recorded responses to open narratives and closed questions, causes of death assigned, and additional information gathered by open narrative. Results Eighteen partner interviews were conducted, with complete data for 11 pairs. Comparing closed questions between interviewers, the median number of differences was 1 (IQR: 0.5–3.5) of an average 65 answered; mean inter-interviewer concordance was 92 % (IQR: 92–99 %). Discrepancies in open narratives were summarized in five categories: demographics, history and care-seeking, diagnoses and symptoms, treatment and cultural. Most discrepancies were seen in the reporting of diagnoses and symptoms (e.g., malaria diagnosis); only one pair demonstrated no clear differences. The average number of clinical symptoms reported was 9 in open narratives and 20 in the closed questions. Open narratives contained additional information on health seeking and social issues surrounding deaths, which closed questions did not gather. Conclusions The information gleaned during open narratives was subject to inter-interviewer variability and contained a limited number of symptom indicators, suggesting that their use for assigning cause of death is questionable. However, they contained rich information on care-seeking, healthcare provision and social factors in the lead-up to death, which may be a valuable source of information for promoting accountable health services.
Published: 2016
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48. Nitrate limitation and ocean acidification interact with UV-B to reduce photosynthetic performance in the diatom Phaeodactylum tricornutum

Author: W. Li, K. Gao, and J. Beardall
Subjects: Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract: It has been proposed that ocean acidification (OA) will interact with other environmental factors to influence the overall impact of global change on biological systems. Accordingly we investigated the influence of nitrogen limitation and OA on the physiology of diatoms by growing the diatom Phaeodactylum tricornutum Bohlin under elevated (1000 μatm; high CO2 – HC) or ambient (390 μatm; low CO2 – LC) levels of CO2 with replete (110 μmol L−1; high nitrate – HN) or reduced (10 μmol L−1; low nitrate – LN) levels of NO3- and subjecting the cells to solar radiation with or without UV irradiance to determine their susceptibility to UV radiation (UVR, 280–400 nm). Our results indicate that OA and UVB induced significantly higher inhibition of both the photosynthetic rate and quantum yield under LN than under HN conditions. UVA or/and UVB increased the cells' non-photochemical quenching (NPQ) regardless of the CO2 levels. Under LN and OA conditions, activity of superoxide dismutase and catalase activities were enhanced, along with the highest sensitivity to UVB and the lowest ratio of repair to damage of PSII. HC-grown cells showed a faster recovery rate of yield under HN but not under LN conditions. We conclude therefore that nutrient limitation makes cells more prone to the deleterious effects of UV radiation and that HC conditions (ocean acidification) exacerbate this effect. The finding that nitrate limitation and ocean acidification interact with UV-B to reduce photosynthetic performance of the diatom P. tricornutum implies that ocean primary production and the marine biological C pump will be affected by OA under multiple stressors.
Published: 2015
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49. Lignin: Historical, Biological, and Materials Perspectives

Author: WOLFGANG G. GLASSER, ROBERT A. NORTHEY, TOR P. SCHULTZ, Joseph L. McCarthy, Aminul Islam, K. Forss, K-E. Fremer, Hendrik van Rensburg, Aldwin M. Anterola, Lanfang H. Levine, Laurence B. Davin, Norman G. Lewis, C. Lapierre, B. Pollet, M. Petit-Conil, G. Pilate, C. Leplé, W. Boerjan, L. Jouanin, Richard F. Helm, Keko Hori, Gyosuke Meshitsuka, Thomas Elder, David C. Young, Darrel D. Nicholas, Y.-Z. Lai, H. Xu, R. Yang, U. P. Agarwal, R. H. Atalla, H. L. Hergert, G. C. Goyal, J. H. Lora, B. Cathala, N. Puff, V. Aguié-Béghin, R. Douillard, B. Monties, L. G. Akim, N. Cordeiro, C. Pascoal Neto, A. Gandini, J. D. Gargulak, S. E. Lebo, Meng-Jiu Chen, John J. Meister, Indrajit Ghosh, Rajesh K. Jain, Yan Li, Simo Sarkanen, G. Toriz, F. Denes, R. A. Young, Josef S. Gratzl, Chen-Loung Chen, Josef Gierer, Ying Liu, Sandra Carriero, Kendall Pye, Dimitris S. Argyropoulos, D. L. Criss, T. H. Fisher, L. L. Ingram, D. J. Beard, K. Poppius-Levlin, A.-S. Jääskeläinen, A. Seisto, A. Fuhrmann, Magnus Paulsson, Arthur J. Ragauskas, Michael Zawadzki, Troy Runge, D. R. Robert, M. Sz, WOLFGANG G. GLASSER, ROBERT A. NORTHEY, TOR P. SCHULTZ, Joseph L. McCarthy, Aminul Islam, K. Forss, K-E. Fremer, Hendrik van Rensburg, Aldwin M. Anterola, Lanfang H. Levine, Laurence B. Davin, Norman G. Lewis, C. Lapierre, B. Pollet, M. Petit-Conil, G. Pilate, C. Leplé, W. Boerjan, L. Jouanin, Richard F. Helm, Keko Hori, Gyosuke Meshitsuka, Thomas Elder, David C. Young, Darrel D. Nicholas, Y.-Z. Lai, H. Xu, R. Yang, U. P. Agarwal, R. H. Atalla, H. L. Hergert, G. C. Goyal, J. H. Lora, B. Cathala, N. Puff, V. Aguié-Béghin, R. Douillard, B. Monties, L. G. Akim, N. Cordeiro, C. Pascoal Neto, A. Gandini, J. D. Gargulak, S. E. Lebo, Meng-Jiu Chen, John J. Meister, Indrajit Ghosh, Rajesh K. Jain, Yan Li, Simo Sarkanen, G. Toriz, F. Denes, R. A. Young, Josef S. Gratzl, Chen-Loung Chen, Josef Gierer, Ying Liu, Sandra Carriero, Kendall Pye, Dimitris S. Argyropoulos, D. L. Criss, T. H. Fisher, L. L. Ingram, D. J. Beard, K. Poppius-Levlin, A.-S. Jääskeläinen, A. Seisto, A. Fuhrmann, Magnus Paulsson, Arthur J. Ragauskas, Michael Zawadzki, Troy Runge, D. R. Robert, and M. Sz
Subjects: Lignin
Published: 1999

50. Taxon-specific responses of Southern Ocean diatoms to Fe enrichment revealed by synchrotron radiation FTIR microspectroscopy

Author: O. Sackett, L. Armand, J. Beardall, R. Hill, M. Doblin, C. Connelly, J. Howes, B. Stuart, P. Ralph, and P. Heraud
Subjects: Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract: Photosynthesis by marine diatoms contributes substantially to global biogeochemical cycling and ecosystem productivity. It is widely accepted that diatoms are extremely sensitive to changes in Fe availability, with numerous in situ experiments demonstrating rapid growth and increased export of elements (e.g. C, Si and Fe) from surface waters as a result of Fe addition. Less is known about the effects of Fe enrichment on the phenotypes of diatoms, such as associated changes in nutritional value – furthermore, data on taxon-specific responses are almost non-existent. Enhanced supply of nutrient-rich waters along the coast of the subantarctic Kerguelen Island provide a valuable opportunity to examine the responses of phytoplankton to natural Fe enrichment. Here we demonstrate the use of synchrotron radiation Fourier Transform Infrared (SR-FTIR) microspectroscopy to analyse changes in the macromolecular composition of diatoms collected along the coast and plateau of Kerguelen Island, Southern Ocean. SR-FTIR microspectroscopy enabled the analysis of individual diatom cells from mixed communities of field-collected samples, thereby providing insight into in situ taxon-specific responses in relation to changes in Fe availability. Phenotypic responses were taxon-specific in terms of intraspecific variability and changes in proteins, amino acids, phosphorylated molecules, silicate/silicic acid and carbohydrates. In contrast to some previous studies, silicate/silicic acid levels increased under Fe enrichment, in conjunction with increases in carbohydrate stores. The highly abundant taxon Fragilariopsis kerguelensis displayed a higher level of phenotypic plasticity than Pseudo-nitzschia spp., while analysis of the data pooled across all measured taxa showed different patterns in macromolecular composition compared to those for individual taxon. This study demonstrates that taxon-specific responses to Fe enrichment may not always be accurately reflected by bulk community measurements, highlighting the need for further research into taxon-specific phenotypic responses of phytoplankton to environmental change.
Published: 2014
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