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396 results on '"Bommier, V."'

1. Full non-LTE spectral line formation III. The case of a two-level atom with broadened upper level

Author

Sampoorna, M., Paletou, F., Bommier, V., and Lagache, T.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Atomic Physics
Abstract

In the present paper we consider the full nonlocal thermodynamic equilibrium (non-LTE) radiation transfer problem. This formalism allows us to account for deviation from equilibrium distribution of both the radiation field and the massive particles. In the present study two-level atoms with broadened upper level represent the massive particles. In the absence of velocity-changing collisions, we demonstrate the analytic equivalence of the full non-LTE source function with the corresponding standard non-LTE partial frequency redistribution (PFR) model. We present an iterative method based on operator splitting techniques to numerically solve the problem at hand. We benchmark it against the standard non-LTE transfer problem for a two-level atom with PFR. We illustrate the deviation of the velocity distribution function of excited atoms from the equilibrium distribution. We also discuss the dependence of the emission profile and the velocity distribution function on elastic collisions and velocity-changing collisions., Comment: Accepted for publication in A&A

Published
2024
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2. Master equation theory applied to the redistribution of polarized radiation in the weak radiation field limit. VI. Application to the Second Solar Spectrum of the Na I D1 & D2 lines: convergence

Author

Bommier, V.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

This paper presents a numerical application of a self-consistent theory of partial redistribution in non-LTE conditions, developed in previous papers of the series. The code was described in a previous paper of this series. However, in that previous paper (number IV of the series), the numerical results were unrealistic. The present paper presents an approximation, which was able to restore the reliability of the outgoing polarization profiles. The convergence of the results is also proved. It is demonstrated that the step increment decreases like 1/N^a, with a > 1, so that the results series behaves like a Riemann series, which is absolutely convergent. However, agreement between the computed and observed linear polarization profiles remains qualitative only. The discrepancy is assigned to the plane parallel atmosphere model, which is insufficient to describe the chromosphere, where these lines are formed. As all the integrals are numerical in the code, it could probably be adapted to more realistic and higher dimensioned model atmospheres. However, it is time consuming for lines having an hyperfine structure as the Na I D lines are. The net linear polarization observed in Na I D1 with the polarimeter ZIMPOL mounted on the McMath-Pierce telescope at Kitt Peak is not confirmed by the present calculations and could be an artefact of instrumental polarization. The presence of instrumental polarization could be confirmed by the higher linear polarization degree observed by this instrument in Na I D2 line center, with respect to the present calculation result, where the magnetic field is not accounted for, when the Hanle effect acts as a depolarizing effect in the Second Solar Spectrum. The observed linear polarization excess is found of the same order of magnitude 0.1% in both line centers, which is also comparable to the instrumental polarization compensation level of this experiment., Comment: 7 pages, 3 figures, accepted in Astronomy and Astrophysics, section "Astrophysical Processes"

Published
2020
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3. 24 synoptic maps of average magnetic field in 296 prominences measured by the Hanle effect during the ascending phase of solar cycle 21

Author

Bommier, V., Leroy, J. L., and Sahal-Brechot, S.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Aims : We present 24 synoptic maps of solar filaments, in which the average unambiguous magnetic field vectors of 296 prominences were determined with Pic-du-Midi observations between 1974 and 1982. This was the ascending phase of cycle 21. Methods : The magnetic field was determined by interpreting the Hanle effect, which is observed in the \ion{He}{i} D$_3$ line. Previous results for the prominence field polarity and prominence chirality were applied to solve the fundamental ambiguity. The measurements were averaged in each prominence for accuracy reasons. Results : The result is twofold. First, alternating field directions can be observed from one neutral line to the next. Second, a general field alignment is found along a solar north-south field that is distorted by the differential rotation effect. The numerical data for the prominences and their magnetic field coordinates are provided as online material associated with this paper., Comment: 31 pages, 27 figures, accepted in Astronomy & Astrophysics, section "Catalogs and Data"

Published
2020
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4. Magnetic field vector ambiguity resolution in a quiescent prominence observed on two consecutive days

Author

Kalewicz, T. and Bommier, V.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Magnetic field vector measurements are always ambiguous, that is, two or more field vectors are solutions of the observed polarisation. The aim of the present paper is to solve the ambiguity by comparing the ambiguous field vectors obtained in the same prominence observed on two consecutive days. The effect of the solar rotation is to modify the scattering angle of the prominence radiation, which modifies the symmetry of the ambiguous solutions. This method, which is a kind of tomography, was successfully applied in the past to the average magnetic field vector of 20 prominences observed at the Pic du Midi. The aim of the present paper is to apply this method to a prominence observed with spatial resolution at the THEMIS telescope (European site at Izana, Tenerife Island). The magnetic field vector is measured by interpretation of the Hanle effect observed in the He I D3 5875.6 A line, within the horizontal field vector hypothesis for simplicity. The ambiguity is first solved by comparing the two pairs of solutions obtained for a "big pixel" determined by averaging the observed Stokes parameters in a large region at the prominence centre. Each pixel is then disambiguated by selecting the closest solution in a propagation from the prominence centre to the prominence boundary. The results previously obtained on averaged prominences are all recovered. The polarity is found to be inverse with a small angle of about -21{\deg} between the magnetic field vector and the long axis of the filament. The magnetic field strength of about 6 G is found to slightly increase with height, as previously observed. The new result is the observed decrease with height, of the absolute value of the angle between the magnetic field vector and the long axis of the filament. This result is in excellent agreement with prominence magnetohydrodynamical models., Comment: 8 pages, 8 figures, version v5, accepted in Astronomy & Astrophysics, Section "The Sun"

Published
2019
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5. Master equation theory applied to the redistribution of polarized radiation in the weak radiation field limit. V. The two-term atom

Author

Bommier, V.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

In previous papers of this series, we presented a formalism able to account for both statistical equilibrium of a multilevel atom and coherent and incoherent scatterings (partial redistribution). aims: This paper provides theoretical expressions of the redistribution function for the two-term atom. This redistribution function includes both coherent (R_II) and incoherent (R_III) scattering contributions with their branching ratios. methods: The expressions were derived by applying the formalism outlined above. The statistical equilibrium equation for the atomic density matrix is first formally solved in the case of the two-term atom with unpolarized and infinitely sharp lower levels. Then the redistribution function is derived by substituting this solution for the expression of the emissivity. results: Expressions are provided for both magnetic and non-magnetic cases. Atomic fine structure is taken into account. Expressions are also separately provided under zero and non-zero hyperfine structure. conclusions: Redistribution functions are widely used in radiative transfer codes. In our formulation, collisional transitions between Zeeman sublevels within an atomic level (depolarizing collisions effect) are taken into account when possible (i.e., in the non-magnetic case). However, the need for a formal solution of the statistical equilibrium as a preliminary step prevents us from taking into account collisional transfers between the levels of the upper term. Accounting for these collisional transfers could be done via a numerical solution of the statistical equilibrium equation system., Comment: 15 pages, no figure, in press in Astronomy & Astrophysics

Published
2017
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6. Evolution of Flare Ribbons, Electric Currents and Quasi-separatrix Layers During an X-class Flare

Author

Janvier, M., Savcheva, A., Pariat, E., Tassev, S., Millholland, S., Bommier, V., McCauley, P., McKillop, S., and Dougan, F.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

The standard model for eruptive flares has in the past few years been extended to 3D. It predicts typical J-shaped photospheric footprints of the coronal current layer, forming at similar locations as the Quasi-Separatrix Layers (QSLs). Such a morphology is also found for flare ribbons observed in the EUV band, as well as in non-linear force-free field (NLFFF) magnetic field extrapolations and models. We study the evolution of the photospheric traces of the current density and flare ribbons, both obtained with the SDO instruments. We investigate the photospheric current evolution during the 6 September 2011 X-class flare (SOL2011-09-06T22:20) from observational data of the magnetic field obtained with HMI. This evolution is compared with that of the flare ribbons observed in the EUV filters of the AIA. We also compare the observed electric current density and the flare ribbon morphology with that of the QSLs computed from the flux rope insertion method/NLFFF model. The NLFFF model shows the presence of a fan-spine configuration of overlying field lines, due to the presence of a parasitic polarity, embedding an elongated flux rope that appears in the observations as two parts of a filament. The QSLs, evolved via a magnetofrictional method, also show similar morphology and evolution as both the current ribbons and the EUV flare ribbons obtained at several times during the flare. For the first time, we propose a combined analysis of the photospheric traces of an eruptive flare, in a complex topology, with direct measurements of electric currents and QSLs from observational data and a magnetic field model. The results, obtained by two different and independent approaches, 1) confirm previous results of current increase during the impulsive phase of the flare, 2) show how NLFFF models can capture the essential physical signatures of flares even in a complex magnetic field topology., Comment: 17 pages, 14 figures, accepted for publication in Astronomy and Astrophysics

Published
2016
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7. Electric current in flares ribbons: observations and 3D standard model

Author

Janvier, Miho, Aulanier, G., Bommier, V., Schmieder, B., Démoulin, P., and Pariat, E.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We present for the first time the evolution of the photospheric electric currents during an eruptive X-class flare, accurately predicted by the standard 3D flare model. We analyze this evolution for the February 15, 2011 flare using HMI/SDO magnetic observations and find that localized currents in \J-shaped ribbons increase to double their pre-flare intensity. Our 3D flare model, developed with the OHM code, suggests that these current ribbons, which develop at the location of EUV brightenings seen with AIA imagery, are driven by the collapse of the flare's coronal current layer. These findings of increased currents restricted in localized ribbons are consistent with the overall free energy decrease during a flare, and the shape of these ribbons also give an indication on how much twisted the erupting flux rope is. Finally, this study further enhances the close correspondence obtained between the theoretical predictions of the standard 3D model and flare observations indicating that the main key physical elements are incorporated in the model., Comment: 12 pages, 7 figures

Published
2014
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8. Solar magnetism eXplorer (SolmeX)

Author

Peter, H., Abbo, L., Andretta, V., Auchere, F., Bemporad, A., Berrilli, F., Bommier, V., Braukhane, A., Casini, R., Curdt, W., Davila, J., Dittus, H., Fineschi, S., Fludra, A., Gandorfer, A., Griffin, D., Inhester, B., Lagg, A., Degl'Innocenti, E. Landi, Maiwald, V., Sainz, R. Manso, Pillet, V. Martinez, Matthews, S., Moses, D., Parenti, S., Pietarila, A., Quantius, D., Raouafi, N. -E., Raymond, J., Rochus, P., Romberg, O., Schlotterer, M., Schuehle, U., Solanki, S., Spadaro, D., Teriaca, L., Tomczyk, S., Bueno, J. Trujillo, and Vial, J. -C.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics, Physics - Space Physics
Abstract

The magnetic field plays a pivotal role in many fields of Astrophysics. This is especially true for the physics of the solar atmosphere. Measuring the magnetic field in the upper solar atmosphere is crucial to understand the nature of the underlying physical processes that drive the violent dynamics of the solar corona -- that can also affect life on Earth. SolmeX, a fully equipped solar space observatory for remote-sensing observations, will provide the first comprehensive measurements of the strength and direction of the magnetic field in the upper solar atmosphere. The mission consists of two spacecraft, one carrying the instruments, and another one in formation flight at a distance of about 200m carrying the occulter to provide an artificial total solar eclipse. This will ensure high-quality coronagraphic observations above the solar limb. Solmex integrates two spectro-polarimetric coronagraphs for off-limb observations, one in the EUV and one in the IR, and three instruments for observations on the disk. The latter comprises one imaging polarimeter in the EUV for coronal studies, a spectro-polarimeter in the EUV to investigate the low corona, and an imaging spectro-polarimeter in the UV for chromospheric studies. SOHO and other existing missions have investigated the emission of the upper atmosphere in detail (not considering polarization), and as this will be the case also for missions planned for the near future. Therefore it is timely that SolmeX provides the final piece of the observational quest by measuring the magnetic field in the upper atmosphere through polarimetric observations., Comment: Submitted to Experimental Astronomy. 30 pages, 19 figures

Published
2011
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9. Magnetic Field Structures in a Facular Region Observed by THEMIS and Hinode

Author

Guo, Y., Schmieder, B., Bommier, V., and Gosain, S.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

The main objective of this paper is to build and compare vector magnetic maps obtained by two spectral polarimeters, i.e. THEMIS/MTR and Hinode SOT/SP, using two inversion codes (UNNOFIT and MELANIE) based on the Milne-Eddington solar atmosphere model. To this end, we used observations of a facular region within active region NOAA 10996 on 23 May 2008, and found consistent results concerning the field strength, azimuth and inclination distributions. Because SOT/SP is free from the seeing effect and has better spatial resolution, we were able to resolve small magnetic polarities with sizes of 1" to 2", and we could detect strong horizontal magnetic fields, which converge or diverge in negative or positive facular polarities. These findings support models which suggest the existence of small vertical flux tube bundles in faculae. A new method is proposed to get the relative formation heights of the multi-lines observed by MTR assuming the validity of a flux tube model for the faculae. We found that the Fe 1 6302.5 \AA line forms at a greater atmospheric height than the Fe 1 5250.2 \AA line., Comment: 20 pages, 9 figures, 3 tables, accepted for publication in Solar Physics

Published
2010
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10. Hanle effect in the solar Ba II D2 line: a diagnostic tool for chromospheric weak magnetic fields

Author

Faurobert, M., Derouich, M., Bommier, V., and Arnaud, J.

Subjects
Astrophysics
Abstract

The physics of the solar chromosphere depends in a crucial way on its magnetic structure. However there are presently very few direct magnetic field diagnostics available for this region. Here we investigate the diagnostic potential of the Hanle effect on the Ba II D2 line resonance polarization for the determination of weak chromospheric turbulent magnetic fields......, Comment: In press in astronomy and astrophysics

Published
2008
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11. Large-scale horizontal flows in the solar photosphere III: Effects on filament destabilization

Author

Roudier, Th., Svanda, M., Meunier, N., Keil, S., Rieutord, M., Malherbe, J. M., Rondi, S., Molodij, G., Bommier, V., and Schmieder, B.

Subjects
Astrophysics
Abstract

We study the influence of large-scale photospheric motions on the estabilization of an eruptive filament, observed on October 6, 7, and 8, 2004, as part of an international observing campaign (JOP 178). Large-scale horizontal flows were invetigated from a series of MDI full-disc Dopplergrams and magnetograms. From the Dopplergrams, we tracked supergranular flow patterns using the local correlation tracking (LCT) technique. We used both LCT and manual tracking of isolated magnetic elements to obtain horizontal velocities from magnetograms. We find that the measured flow fields obtained by the different methods are well-correlated on large scales. The topology of the flow field changed significantly during the filament eruptive phase, suggesting a possible coupling between the surface flow field and the coronal magnetic field. We measured an increase in the shear below the point where the eruption starts and a decrease in shear after the eruption. We find a pattern in the large-scale horizontal flows at the solar surface that interact with differential rotation. We conclude that there is probably a link between changes in surface flow and the disappearance of the eruptive filament., Comment: 9 pages, 10 figures, accepted in A&A

Published
2007
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13. The Solar Magnetic Field: Surface and Upper Layers, Network and Internetwork Field

Author

Bommier, V., Beiglböck, Wolf, editor, Ehlers, Jürgen, editor, Hepp, Klaus, editor, Weidenmüller, Hans A., editor, Beig, Robert, editor, Domcke, Wolfgang, editor, Englert, Berthold-Georg, editor, Frisch, Uriel, editor, Hänggi, Peter, editor, Hasinger, Günther, editor, Hillebrandt, Wolfgang, editor, Jaffe, Robert L., editor, Janke, Wolfhard, editor, von Löhneysen, H., editor, Mangano, Michelangelo, editor, Raimond, Jean-Michel, editor, Sornette, Didier, editor, Theisen, Stefan, editor, Weise, W., editor, Zittartz, Johannes, editor, Guinea, Francisco, editor, Vollhardt, Dieter, editor, Rozelot, Jean-Pierre, editor, and Neiner, Coralie, editor

Published
2009
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14. The European Solar Telescope

Author

Quintero Noda, C., primary, Schlichenmaier, R., additional, Bellot Rubio, L. R., additional, Löfdahl, M. G., additional, Khomenko, E., additional, Jurčák, J., additional, Leenaarts, J., additional, Kuckein, C., additional, González Manrique, S. J., additional, Gunár, S., additional, Nelson, C. J., additional, de la Cruz Rodríguez, J., additional, Tziotziou, K., additional, Tsiropoula, G., additional, Aulanier, G., additional, Aboudarham, J., additional, Allegri, D., additional, Alsina Ballester, E., additional, Amans, J. P., additional, Asensio Ramos, A., additional, Bailén, F. J., additional, Balaguer, M., additional, Baldini, V., additional, Balthasar, H., additional, Barata, T., additional, Barczynski, K., additional, Barreto Cabrera, M., additional, Baur, A., additional, Béchet, C., additional, Beck, C., additional, Belío-Asín, M., additional, Bello-González, N., additional, Belluzzi, L., additional, Bentley, R. D., additional, Berdyugina, S. V., additional, Berghmans, D., additional, Berlicki, A., additional, Berrilli, F., additional, Berkefeld, T., additional, Bettonvil, F., additional, Bianda, M., additional, Bienes Pérez, J., additional, Bonaque-González, S., additional, Brajša, R., additional, Bommier, V., additional, Bourdin, P.-A., additional, Burgos Martín, J., additional, Calchetti, D., additional, Calcines, A., additional, Calvo Tovar, J., additional, Campbell, R. J., additional, Carballo-Martín, Y., additional, Carbone, V., additional, Carlin, E. S., additional, Carlsson, M., additional, Castro López, J., additional, Cavaller, L., additional, Cavallini, F., additional, Cauzzi, G., additional, Cecconi, M., additional, Chulani, H. M., additional, Cirami, R., additional, Consolini, G., additional, Coretti, I., additional, Cosentino, R., additional, Cózar-Castellano, J., additional, Dalmasse, K., additional, Danilovic, S., additional, De Juan Ovelar, M., additional, Del Moro, D., additional, del Pino Alemán, T., additional, del Toro Iniesta, J. C., additional, Denker, C., additional, Dhara, S. K., additional, Di Marcantonio, P., additional, Díaz Baso, C. J., additional, Diercke, A., additional, Dineva, E., additional, Díaz-García, J. J., additional, Doerr, H.-P., additional, Doyle, G., additional, Erdelyi, R., additional, Ermolli, I., additional, Escobar Rodríguez, A., additional, Esteban Pozuelo, S., additional, Faurobert, M., additional, Felipe, T., additional, Feller, A., additional, Feijoo Amoedo, N., additional, Femenía Castellá, B., additional, Fernandes, J., additional, Ferro Rodríguez, I., additional, Figueroa, I., additional, Fletcher, L., additional, Franco Ordovas, A., additional, Gafeira, R., additional, Gardenghi, R., additional, Gelly, B., additional, Giorgi, F., additional, Gisler, D., additional, Giovannelli, L., additional, González, F., additional, González, J. B., additional, González-Cava, J. M., additional, González García, M., additional, Gömöry, P., additional, Gracia, F., additional, Grauf, B., additional, Greco, V., additional, Grivel, C., additional, Guerreiro, N., additional, Guglielmino, S. L., additional, Hammerschlag, R., additional, Hanslmeier, A., additional, Hansteen, V., additional, Heinzel, P., additional, Hernández-Delgado, A., additional, Hernández Suárez, E., additional, Hidalgo, S. L., additional, Hill, F., additional, Hizberger, J., additional, Hofmeister, S., additional, Jägers, A., additional, Janett, G., additional, Jarolim, R., additional, Jess, D., additional, Jiménez Mejías, D., additional, Jolissaint, L., additional, Kamlah, R., additional, Kapitán, J., additional, Kašparová, J., additional, Keller, C. U., additional, Kentischer, T., additional, Kiselman, D., additional, Kleint, L., additional, Klvana, M., additional, Kontogiannis, I., additional, Krishnappa, N., additional, Kučera, A., additional, Labrosse, N., additional, Lagg, A., additional, Landi Degl’Innocenti, E., additional, Langlois, M., additional, Lafon, M., additional, Laforgue, D., additional, Le Men, C., additional, Lepori, B., additional, Lepreti, F., additional, Lindberg, B., additional, Lilje, P. B., additional, López Ariste, A., additional, López Fernández, V. A., additional, López Jiménez, A. C., additional, López López, R., additional, Manso Sainz, R., additional, Marassi, A., additional, Marco de la Rosa, J., additional, Marino, J., additional, Marrero, J., additional, Martín, A., additional, Martín Gálvez, A., additional, Martín Hernando, Y., additional, Masciadri, E., additional, Martínez González, M., additional, Matta-Gómez, A., additional, Mato, A., additional, Mathioudakis, M., additional, Matthews, S., additional, Mein, P., additional, Merlos García, F., additional, Moity, J., additional, Montilla, I., additional, Molinaro, M., additional, Molodij, G., additional, Montoya, L. M., additional, Munari, M., additional, Murabito, M., additional, Núñez Cagigal, M., additional, Oliviero, M., additional, Orozco Suárez, D., additional, Ortiz, A., additional, Padilla-Hernández, C., additional, Paéz Mañá, E., additional, Paletou, F., additional, Pancorbo, J., additional, Pastor Cañedo, A., additional, Pastor Yabar, A., additional, Peat, A. W., additional, Pedichini, F., additional, Peixinho, N., additional, Peñate, J., additional, Pérez de Taoro, A., additional, Peter, H., additional, Petrovay, K., additional, Piazzesi, R., additional, Pietropaolo, E., additional, Pleier, O., additional, Poedts, S., additional, Pötzi, W., additional, Podladchikova, T., additional, Prieto, G., additional, Quintero Nehrkorn, J., additional, Ramelli, R., additional, Ramos Sapena, Y., additional, Rasilla, J. L., additional, Reardon, K., additional, Rebolo, R., additional, Regalado Olivares, S., additional, Reyes García-Talavera, M., additional, Riethmüller, T. L., additional, Rimmele, T., additional, Rodríguez Delgado, H., additional, Rodríguez González, N., additional, Rodríguez-Losada, J. A., additional, Rodríguez Ramos, L. F., additional, Romano, P., additional, Roth, M., additional, Rouppe van der Voort, L., additional, Rudawy, P., additional, Ruiz de Galarreta, C., additional, Rybák, J., additional, Salvade, A., additional, Sánchez-Capuchino, J., additional, Sánchez Rodríguez, M. L., additional, Sangiorgi, M., additional, Sayède, F., additional, Scharmer, G., additional, Scheiffelen, T., additional, Schmidt, W., additional, Schmieder, B., additional, Scirè, C., additional, Scuderi, S., additional, Siegel, B., additional, Sigwarth, M., additional, Simões, P. J. A., additional, Snik, F., additional, Sliepen, G., additional, Sobotka, M., additional, Socas-Navarro, H., additional, Sola La Serna, P., additional, Solanki, S. K., additional, Soler Trujillo, M., additional, Soltau, D., additional, Sordini, A., additional, Sosa Méndez, A., additional, Stangalini, M., additional, Steiner, O., additional, Stenflo, J. O., additional, Štěpán, J., additional, Strassmeier, K. G., additional, Sudar, D., additional, Suematsu, Y., additional, Sütterlin, P., additional, Tallon, M., additional, Temmer, M., additional, Tenegi, F., additional, Tritschler, A., additional, Trujillo Bueno, J., additional, Turchi, A., additional, Utz, D., additional, van Harten, G., additional, van Noort, M., additional, van Werkhoven, T., additional, Vansintjan, R., additional, Vaz Cedillo, J. J., additional, Vega Reyes, N., additional, Verma, M., additional, Veronig, A. M., additional, Viavattene, G., additional, Vitas, N., additional, Vögler, A., additional, von der Lühe, O., additional, Volkmer, R., additional, Waldmann, T. A., additional, Walton, D., additional, Wisniewska, A., additional, Zeman, J., additional, Zeuner, F., additional, Zhang, L. Q., additional, Zuccarello, F., additional, and Collados, M., additional

Published
2022
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19. Electron thermal escape in the Sun

Author

Bommier, V., Wolk, Scott, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), 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)-Université de Paris (UP), and European Physical Society (EPS)

Subjects
[PHYS]Physics [physics], The Sun and the Heliosphere, Sun: Magnetic Fields, Sun: electrons, electrons, magnetic fields, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 7. Clean energy, electric fields, Sun: surface, 13. Climate action, Astrophysics::Solar and Stellar Astrophysics, solar-type star internal structure, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Sun internal structure
Abstract

International audience; Magnetic field vector observations in the solar photosphere have generally revealed a non-zero value of the divergence: the vertical field component gradient is found on the order of 3 G/km when the horizontal field component gradient is of 0.3 G/km only. This has first to be assigned to the fact that the measured quantity is the magnetic field H, which is related to the divergence-free magnetic induction B by the law B=µ0(H+M), where M is the magnetization. In plasmas like the solar photosphere, magnetization results from plasma diamagnetism and spiral movement of charged particles about the magnetic field. It can be observed that in the solar interior the electron thermal velocity is much larger than the escape velocity from both gravity and proton attraction. A model of this is presented in the related paper (Bommier, V., "Solar photosphere magnetization", 2020, A&A, 634, A40). The electrons escape from lower layers in a quasi-static spreading, and accumulate in the photosphere. Therefore, the electron density at surface is increased but decreases with height at surface, which enables the observed values because divH = -divM. Such a structure is probably at play in the solar-type stars. Besides, solar magnetohydrodynamics must include the fact that the quantity measured by Zeeman effect is H (4 demonstrations in the paper), which is related to the electric current j by the Maxwell relation rotH = j, where j is itself submitted to the Lorentz force j x B, where B is the divergence-free magnetic induction.

Published
2021
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22. 24 synoptic maps of 296 prominence average magnetic fields measured by Hanle effect during cycle XXI ascending phase

Author

Bommier, V., Leroy, J. L., Sahal-Bréchot, S., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-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), and Bommier, Véronique

Subjects
[PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], [PHYS] Physics [physics]
Abstract

17 pages, 24 figures, submitted to Astronomy & Astrophysics, section "Catalogs and Data"; Aims : The aim of the present paper is to publish 24 synoptic maps of solar filaments, in which 296 prominence average unambiguous magnetic field vectors were determined by Pic-du-Midi observations between 1974 and 1982, which is the ascending phase of cycle XXI. Methods : The magnetic field was determined by interpretation of the Hanle effect observed in the He I D3 line. Previous results about the prominence field polarity and prominence chirality were applied to solve the fundamental ambiguity. The measurements were averaged in each prominence for accuracy reasons. Results : The result is twofold. First, alternating field directions can be observed from one neutral line to the next one. Second, a general field alignment is found along a solar North-South field distorted under the differential rotation effect.

Published
2020

24. Predictions on the application of the Hanle effect to map the surface magnetic field of Jupiter

Author

Ben-Jaffel, L., Harris, W., Bommier, V., Roesler, F., Ballester, G.E., and Jossang, J.

Subjects
Astronomy, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2005.01.021 Byline: L. Ben-Jaffel (a), W. Harris (b), V. Bommier (c), F. Roesler (d), G.E. Ballester (e), J. Jossang (a) Keywords: Jupiter; Magnetic fields; Polarimetry; Spectroscopy; Ultraviolet observations Abstract: In this paper we evaluate the possibility of detecting, for the first time, the surface magnetic field of Jupiter ([approximately equal to]1 bar level) by observing the change of linear polarization induced by the Hanle effect on the H Lyman-alpha (Ly[alpha]) emission line of the planet. We find that, indeed, the Hanle effect, which results from the interaction between a local magnetic field and the atomic polarization induced by absorption of anisotropic radiation, is sensitive to relatively weak values of the strength of the magnetic fields expected on planets. First, we show that for the Ly[alpha] emission backscattered by atomic H in the presence of a magnetic field, the Hanle effect is polarizing. This new result is in total contrast to the depolarizing effect predicted and observed for emission lines scattered at right angles in solar prominences. Additionally, to estimate the polarization rate for the case of Jupiter, we have considered three magnetic field models: a dipole field for reference, an O.sub.4 based model [Connerney, J.E.P., 1981. The magnetic field of Jupiter -- A generalized inverse approach. J. Geophys. Res. 86, 7679-7693], and finally, an O.sub.6 based model [Khurana, K.K., 1997. Euler potential models of Jupiter's magnetospheric field. J. Geophys. Res. 102, 11295-11306]. In all models, we show that for the jovian backscattered Ly[alpha] line, the Hanle effect does enhance the Ly[alpha] linear polarization; the polarization rate may exceed 2% at specific regions of the jovian disc, making detection possible either remotely or from an orbiter around Jupiter. In general, depending on the instrumental sensitivity and the observing strategy used, we show that accurate mapping of the linear polarization rate at the planetary surface (thermosphere) or off-disc (corona) may provide a rather accurate estimate of the jovian total magnetic field strength on large area scales. Author Affiliation: (a) Institut d'Astrophysique de Paris, CNRS-UPMC, 98 bis, Blvd Arago, F-75014 Paris, France (b) Department of Earth and Space Science, Box 351310, Seattle, WA 98195, USA (c) LERMA-CNRS UMR8112, Observatoire de Paris, Section de Meudon, 5 Place Jules Janssen, 92195 Meudon, France (d) Physics Department, 1150 University Avenue, Madison, WI 53706, USA (e) Lunar and Planetary Laboratory, 1541 East University Boulevard, Tucson, AZ 85721-0063, USA Article History: Received 19 September 2004; Revised 3 January 2005

Published
2005

29. Would the Sun's surface be negatively charged ?

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Annual Meeting of the PLAS@PAR LabEx community

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2019

31. Le problème des gradients de champ magnétique dans et autour des taches solaires

Author

Bommier, V., Démoulin, P., Dubau., J., Meyer-Vernet, N., Tchang-Brillet, Wan-Ü Lydia, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-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), and Bommier, Véronique

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

National audience

Published
2018

32. Pièges à ions multichargés dans la Couronne Solaire

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and organisée par J. Laskar

Subjects
[PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2018

33. Ion traps at the Sun: observational evidence

Author

Musset, S., Fleishman, G., Bommier, V., Glesener, L., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

35. Interpretation of Hanle effect measurements in the Solar Corona: promises and difficulties

Author

Bommier, V., Bommier, Véronique, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and COSPAR 2018 42nd Assembly

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics::Solar and Stellar Astrophysics, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience; After having recalled the main features of the Hanle effect, and of its application to coronal lines, the promises and difficulties of the measurement interpretation in terms of magnetic field vector diagnostics, will be investigated, based on Bommier, V., Leroy, J.L., and Sahal-Bréchot, S., 1981, A&A, 100, 231, and in the light of the new instrumentation presently available or in project, as well as data-driven modeling present possibilities. The feasibility of measuring the Coronal magnetic field by interpretation of the Zeeman effect observed in the infrared, will also be investigated.

Published
2018

36. Divergence du champ magnétique dans la photosphère solaire

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Société Française de Physique

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2017

37. Transfert de rayonnement polarisé avec redistribution partielle

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and organisée par J. Laskar

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2017

38. Solar magnetic fields and plasma physics (from measurements)

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Excellence 'Plasmas in Paris' (LabEx PLAS@PAR)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2017

39. The anisotropic Debye shielding as visible in sunspot photosphere

Author

Bommier, V., Bommier, Véronique, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience

Published
2017

40. Physique atomique pour l'astrophysique: de l'effet Hanle au transfert de rayonnment

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2016

41. The problem of the magnetic field gradients in sunspots: discussion guidelines

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique solaire, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and organized by V. Bommier at Centre International d'Ateliers Scientifiques de l'Observatoire de Paris

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

42. Vertical photospheric currents: footprints of eruptive flux ropes in the corona

Author

Schmieder, B., Janvier, M., Bommier, V., Aulanier, G., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), 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)-Université de Paris (UP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), AGU Chapman Conference on 'Currents in Geospace and Beyond', Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

43. Non-perturbative theory of radiative scattering, in the weak radiation field limit

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

44. Résolution de l'ambiguïté fondamentale dans les mesures du vecteur champ magnétique de la photosphère solaire

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique solaire, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2016

45. La mesure du champ magnétique solaire par analyse de la lumière

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2015

46. Polarization in spectral lines formed by scattering: from the line center to the far wings

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique solaire, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2015

47. SCP calculations of electron and ion impact widths and shifts of spectral lines

Author

Sahal-Bréchot, S., Dimitrijević, M., Bommier, V., Šimić, Z., Bommier, Véronique, 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 d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS-PSL)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR.SR] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience

Published
2015

48. Theoretical polarization spectrum of Na I D1 & D2 near the solar limb

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IAU (International Astronomical Union) Symposium 305, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique solaire, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS]Physics [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2014

49. The thermospheric auroral red line polarization: comparison between theory and observations

Author

Lilensten, J., Bommier, V., Barthélemy, M., Bernard , D., Lamy, H., Moen, J., Johnsen, M.G., Lovhaug, U.P., Pitout, F., Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2014

50. Interpretation of the observed magnetic flux height decrease in the solar photosphere

Author

Bommier, V., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), In memory of Jean Heyvaerts, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique solaire, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS]Physics [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2014

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