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20 results on '"Kazakov, Ye. O."'

1. 4D and 5D phase-space tomography using slowing-down physics regularization

Author

W7-X Team, Schmidt, B. S., Salewski, M., Moseev, D., Baquero-Ruiz, M., Hansen, P. C., Eriksson, J., Ford, O., Gorini, G., Järleblad, H., Kazakov, Ye O., Kulla, D., Lazerson, S., Mencke, J. E., Mykytchuk, D., Nocente, M., Poloskei, P., Rud, M., Snicker, A., Stagner, L., Äkäslompolo, S., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Technical University of Denmark, Max-Planck-Institut für Plasmaphysik, Swiss Federal Institute of Technology Lausanne, Uppsala University, University of Milan - Bicocca, Royal Military Academy, Department of Applied Physics, General Atomics, Aalto-yliopisto, and Aalto University

Subjects
Technology, Nuclear and High Energy Physics, Tokamak, Atom and Molecular Physics and Optics, NBI, tomography, Condensed Matter Physics, Fusion, Plasma and Space Physics, slowing-down, Fusion, plasma och rymdfysik, stellarator, Atom- och molekylfysik och optik, fast ions, ddc:600, Den kondenserade materiens fysik
Abstract

Funding Information: This work has been carried out within the framework of the EUROfusion Consortium, partially funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200—EUROfusion). The Swiss contribution to this work has been funded by the Swiss State Secretariat for Education, Research and Innovation (SERI). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union, the European Commission or SERI. Neither the European Union nor the European Commission nor SERI can be held responsible for them. Further, the assistance provided by Friedemann Herold was greatly appreciated. Publisher Copyright: © 2023 The Author(s). Published on behalf of IAEA by IOP Publishing Ltd. We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections of these functions. The fast-ion phase-space distribution functions originating from neutral beam injection (NBI) at TCV and Wendelstein 7-X (W7-X) at full, half, and one-third injection energies can be distinguished and particle densities of each component inferred based on 20 synthetic spectra of projected velocities at TCV and 680 at W7-X. Further, we demonstrate that an expansion into a basis of slowing-down distribution functions is equivalent to regularization using slowing-down physics as prior information. Using this technique in a Tikhonov formulation, we infer the particle density fractions for each NBI energy for each NBI beam from synthetic measurements, resulting in six unknowns at TCV and 24 unknowns at W7-X. Additionally, we show that installing 40 LOS in each of 17 ports at W7-X, providing full beam coverage and almost full angle coverage, produces the highest quality reconstructions.

Published
2023

2. Predictive simulations of NBI ion power load to the ICRH antenna in Wendelstein 7-X

Author

Kontula, J., Äkäslompolo, S., Ikäheimo, A., Lazerson, S., Kurki-Suonio, T., Hartmann, D., Rust, N., McNeely, P., Kazakov, Ye O., Ongena, J., W7X-Team, Department of Applied Physics, Max-Planck-Institut für Plasmaphysik, Fusion and Plasma Physics, Royal Military Academy, Aalto-yliopisto, Aalto University, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Technology, stellarator, Nuclear Energy and Engineering, ASCOT, NBI, Wendelstein 7-X, fast ions, Condensed Matter Physics, ddc:600, ICRH
Abstract

Funding Information: The calculations were performed on Marconi-Fusion, the High Performance Computer at the CINECA headquarters in Bologna (Italy). The computational resources provided by Aalto Science-IT project are also acknowledged. This work was partially funded by the Academy of Finland Project No. 298126. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2022 under Grant Agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. | openaire: EC/H2020/633053/EU//EUROfusion In Wendelstein 7-X (W7-X), a new ion cyclotron resonance heating (ICRH) antenna will be commissioned during the operational campaign OP2.1. The antenna will have to sustain power loads not only from thermal plasma and radiation but also fast ions. Predictive simulations of fast-ion power loads to the antenna components are therefore important to establish safe operational limits. In this work, the fast-ion power loads from the W7-X neutral beam injection (NBI) system to the ICRH antenna was simulated using the ASCOT suite of codes. Five reference magnetic configurations and five antenna positions were considered to provide an overview of power load behavior under various operating conditions. The NBI power load was found to have an exponential dependence on the antenna insertion depth. Differences between magnetic configurations were significant, with the antenna limiter power load varying between 380 W and 100 kW depending on the configuration. Qualitative differences in power load patterns between configurations were also observed, with the low mirror and low iota configurations exhibiting higher loads to the sensitive antenna straps. The local fast-ion power flux to the antenna limiter was also considered and found to exceed the 2.0 MW m−2 steady-state safety limit only in specific cases. The NBI system might thus pose a safety concern to the ICRH antenna during concurrent NBI-ICRH operation, but additional heat propagation simulations of antenna components are needed to establish more realistic operational time limits.

Published
2023

3. Simultaneous measurements of unstable and stable Alfv\'en Eigenmodes in JET

Author

Tinguely, R. A., Gonzalez-Martin, J., Puglia, P. G., Fil, N., Dowson, S., Porkolab, M., Kumar, I., Podestà, M., Baruzzo, M., Fasoli, A., Kazakov, Ye. O., Nave, M. F. F., Nocente, M., Ongena, J., Štancar, Ž., and Contributors, JET

Subjects
Physics - Plasma Physics
Abstract

In this paper, we report the novel experimental observation of both unstable and stable Toroidicity-induced Alfv\'en Eigenmodes (TAEs) measured simultaneously in a JET tokamak plasma. The three-ion-heating scheme (D-DNBI-3He) is employed to accelerate deuterons to MeV energies, thereby destabilizing TAEs with toroidal mode numbers n = 3-5, each decreasing in mode amplitude. At the same time, the Alfv\'en Eigenmode Active Diagnostic resonantly excites a stable n = 6 TAE with total normalized damping rate $-\gamma/\omega_0 \approx$ 1%-4%. Hybrid kinetic-MHD modeling with codes NOVA-K and MEGA both find eigenmodes with similar frequencies, mode structures, and radial locations as in experiment. NOVA-K demonstrates good agreement with the n = 3, 4, and 6 TAEs, matching the damping rate of the n = 6 mode within uncertainties and identifying radiative damping as the dominant contribution. Improved agreement is found with MEGA for all modes: the unstable n = 3-5 and stable n = 2, 6 modes, with the latter two stabilized by higher intrinsic damping and lower fast ion drive, respectively. While some discrepancies remain to be resolved, this unique validation effort gives us confidence in TAE stability predictions for future fusion devices.

Published
2022

4. The hidden uncertainties in particle balance calculations and their implications for assessment of plasma performance

Author

Teplukhina, A. A., Poli, F. M., Podesta, M., Gorelenkova, M., Szepesi, G., Kazakov, Ye. O., Baranov, Y., Stancar, Z., and Contributors, the JET

Subjects
Plasma Physics (physics.plasm-ph), inorganic chemicals, Physics::Plasma Physics, FOS: Physical sciences, Physics - Plasma Physics
Abstract

Predictive simulations of mixed plasma discharges, like deuterium-tritium plasmas, rely on self-consistent models for particle transport. These models have to be validated with interpretive analysis of existing experiments. Accounting for uncertainties in the particle balance equation is important for modelling of mixed-plasma discharges because simulation results are directly affected by plasma composition. JET deuterium and mixed hydrogen-deuterium plasma discharges heated by neutral beams only are analysed with the TRANSP code. Influence of prescribed quantities and terms entering into the particle balance equation is quantitatively assessed on the computed plasma parameters, in particular on the neutron rate and the plasma energy. Large uncertainties in the prescribed ion temperature, plasma rotation and impurity content might result in a noticeable over- or underestimate of the computed neutron rate. A significant difference in the time evolution of the measured and computed neutron rate is observed in the interpretive simulations if same diffusivity for electrons and thermal ions is assumed. Increased thermal deuterium ion transport is required to reach agreement with the plasma composition measured at the plasma edge and the measured neutron rate. Thermal ion density computed with the particle balance equation is mostly affected by the ion outflux term.

Published
2022

5. Excitation of Alfven eigenmodes by fusion-born alpha-particles in D-He-3 plasmas on JET

Author

Kiptily, V.G., Kazakov, Ye. O., Nocente, M., Ongena, J., Belli, F., Dreval, M., Craciunescu, T., Eriksson, J., Fitzgerald, M., Giacomelli, L., Goloborodko, V., Iliasova, M.V., Khilkevitch, E.M., Rigamonti, D., Sahlberg, A., Salewski, M., Shevelev, A.E., Garcia, J., Oliver, H.J.C., Sharapov, S.E., Stancar, Z., Weisen, H., Kiptily, V, Kazakov, Y, Nocente, M, Ongena, J, Belli, F, Dreval, M, Craciunescu, T, Eriksson, J, Fitzgerald, M, Giacomelli, L, Goloborodko, V, Iliasova, M, Khilkevitch, E, Rigamonti, D, Sahlberg, A, Salewski, M, Shevelev, A, Garcia, J, Oliver, H, Sharapov, S, Stancar, Z, and Weisen, H

Subjects
profile, okamak, Condensed Matter Physics, MHD instabilitie, Fusion, Plasma and Space Physics, fusion-born alpha-particles, fusion-born alpha-particle, Fusion, plasma och rymdfysik, Nuclear Energy and Engineering, Physics::Plasma Physics, fast-ion diagnostic, fast-ion diagnostics, MHD instabilities, tokamak
Abstract

Alfvén eigenmode (AE) instabilities driven by alpha-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall. For the efficient generation of fusion alpha-particles from D-3He fusion reaction, the three-ion radio frequency scenario was used to accelerate the neutral beam injection 100 keV deuterons to higher energies in the core of mixed D-3He plasmas at high concentrations of 3He. A large variety of fast-ion driven magnetohydrodynamic modes were observed, including the elliptical Alfvén eigenmodes (EAEs) with mode numbers n = −1 and axisymmetric modes with n = 0 in the frequency range of EAEs. The simultaneous observation of these modes indicates the presence of rather strong alpha-particle population in the plasma with a ‘bump-on-tail’ shaped velocity distribution. Linear stability analysis and Fokker–Planck calculations support the observations. Experimental evidence of the AEs excitation by fusion-born alpha-particles in the D-3He plasma is provided by neutron and gamma-ray diagnostics as well as fast-ion loss measurements. We discuss an experimental proposal for the planned full-scale D-T plasma experiments on JET based on the physics insights gained from these experiments.

Published
2022

6. A novel measurement of marginal Alfv\'{e}n Eigenmode stability during high power auxiliary heating in JET

Author

Tinguely, R. A., Fil, N., Puglia, P. G., Dowson, S., Porkolab, M., Guillemot, V., Podestà, M., Baruzzo, M., Dumont, R., Fasoli, A., Fitzgerald, M., Kazakov, Ye. O., Nave, M. F. F., Nocente, M., Ongena, J., Sharapov, S. E., Štancar, Ž., and Contributors, JET

Subjects
Physics::Plasma Physics, Physics - Plasma Physics
Abstract

The interaction of Alfv\'{e}n Eigenmodes (AEs) and energetic particles is one of many important factors determining the success of future tokamaks. In JET, eight in-vessel antennas were installed to actively probe stable AEs with frequencies ranging 25-250 kHz and toroidal mode numbers $\vert n \vert < 20$. During the 2019-2020 deuterium campaign, almost 7500 resonances and their frequencies $f_0$, net damping rates $\gamma < 0$, and toroidal mode numbers were measured in almost 800 plasma discharges. From a statistical analysis of this database, continuum and radiative damping are inferred to increase with edge safety factor, edge magnetic shear, and when including non-ideal effects. Both stable AE observations and their associated damping rates are found to decrease with $\vert n \vert$. Active antenna excitation is also found to be ineffective in H-mode as opposed to L-mode; this is likely due to the increased edge density gradient's effect on accessibility and ELM-related noise's impact on mode identification. A novel measurement is reported of a marginally stable, edge-localized Ellipticity-induced AE probed by the antennas during high-power auxiliary heating (ICRH and NBI) up to 25 MW. NOVA-K kinetic-MHD simulations show good agreement with experimental measurements of $f_0$, $\gamma$, and $n$, indicating the dominance of continuum and electron Landau damping in this case. Similar experimental and computational studies are planned for the recent hydrogen and ongoing tritium campaigns, in preparation for the upcoming DT campaign.

Published
2021

7. Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

W7-X Team, Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., Höfel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., Äkäslompolo, S., Alcusón, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., Bähner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Böckenhoff, D., Böswirth, B., Böttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttenschön, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Molin, A. da, Silva, A. da, Pena, A. de la, Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Köchl, F., Kolesnichenko, Y., Könies, A., König, R., Kornejew, P., Koschinsky, J.-P., Köster, F., Krämer, M., Krampitz, R., Krämer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lücke, A., Lumsdaine, A., Lutsenko, V., Maaßberg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morisaki, T., Moseev, D., Murakami, S., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ölmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuß, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Pölöskei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., Röhlinger, H., Romé, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schlüter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szabó, V., Szabolics, T., Szepesi, T., Szökefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipán, S., Unterberg, B., Vakulchyk, I., Valet, S., Vanó, L., Eeten, P. van, Milligen, B. van, Vuuren, A. J. van, Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Stechow, A. von, Vorköper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., Zuin, M., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Applied Physics and Science Education, Science and Technology of Nuclear Fusion, Turbulence in Fusion Plasmas, and European Commission

Subjects
Magnetically Confined Plasmas, Tokamak, Design, Helias, Nuclear engineering, Magnetically confined plasmas, 01 natural sciences, 7. Clean energy, Article, Plasma physics, 010305 fluids & plasmas, law.invention, law, Physics::Plasma Physics, 0103 physical sciences, Nuclear fusion, 010306 general physics, Engineering & allied operations, Stellarator, Physics, Plasma fusion, Multidisciplinary, Toroid, biology, Plasma Physics, Física, Magnetic confinement fusion, Plasma, biology.organism_classification, Energía Nuclear, ddc:620, Wendelstein 7-X
Abstract

Research on magnetic confinement of high-temperature plasmas has the ultimate goal of harnessing nuclear fusion for the production of electricity. Although the tokamak1 is the leading toroidal magnetic-confinement concept, it is not without shortcomings and the fusion community has therefore also pursued alternative concepts such as the stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) magnetic field geometry. The availability of this additional dimension opens up an extensive configuration space for computational optimization of both the field geometry itself and the current-carrying coils that produce it. Such an optimization was undertaken in designing Wendelstein 7-X (W7-X)2, a large helical-axis advanced stellarator (HELIAS), which began operation in 2015 at Greifswald, Germany. A major drawback of 3D magnetic field geometry, however, is that it introduces a strong temperature dependence into the stellarator’s non-turbulent ‘neoclassical’ energy transport. Indeed, such energy losses will become prohibitive in high-temperature reactor plasmas unless a strong reduction of the geometrical factor associated with this transport can be achieved; such a reduction was therefore a principal goal of the design of W7-X. In spite of the modest heating power currently available, W7-X has already been able to achieve high-temperature plasma conditions during its 2017 and 2018 experimental campaigns, producing record values of the fusion triple product for such stellarator plasmas3,4. The triple product of plasma density, ion temperature and energy confinement time is used in fusion research as a figure of merit, as it must attain a certain threshold value before net-energy-producing operation of a reactor becomes possible1,5. Here we demonstrate that such record values provide evidence for reduced neoclassical energy transport in W7-X, as the plasma profiles that produced these results could not have been obtained in stellarators lacking a comparably high level of neoclassical optimization., Previously documented record values of the fusion triple product in the stellarator Wendelstein 7-X are shown to be evidence for reduced neoclassical energy transport in this optimized device.

Published
2021

8. Publisher Correction: Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., H��fel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., ��k��slompolo, S., Alcus��n, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., B��hner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., B��ckenhoff, D., B��swirth, B., B��ttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Br��uer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttensch��n, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., De La Pena, A., Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., Garc��a Rega��a, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., H��lting, A., H��schen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., K��chl, F., Kolesnichenko, Y., K��nies, A., K��nig, R., Kornejew, P., Koschinsky, J.-P., K��ster, F., Kr��mer, M., Krampitz, R., Kr��mer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., K��hner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., L��cke, A., Lumsdaine, A., Lutsenko, V., Maa��berg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., M��nnich, T., Morisaki, T., Moseev, D., Murakami, S., N��fr��di, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., N��hrenberg, C., N��hrenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., ��lmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfu��, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., P��l��skei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., R��csei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., R��hlinger, H., Rom��, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., S��nchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schl��ter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schr��der, M., Schr��der, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipli��, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szab��, V., Szabolics, T., Szepesi, T., Sz��kefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulip��n, S., Unterberg, B., Vakulchyk, I., Valet, S., Van��, L., Van Eeten, P., Van Milligen, B., Van Vuuren, A. J., Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Von Stechow, A., Vork��per, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., and Zuin, M.

Subjects
Chemical engineering, ddc:660
Published
2021

9. Towards enhanced performance in fusion plasmas via turbulence suppression by MeV ions

Author

Mazzi, S., Garcia, J., Zarzoso, D., Kazakov, Ye. O., Ongena, J., Nocente, M., Dreval, M., Stancar, Z., Szepesi, G., Eriksson, J., Sahlberg, A., Benkadda, S., Aix-Marseille Université CNRS, UMR 7345-PIIM Laboratory, Marseille, France, CEA, IRFM, F-13108, Saint Paul lez Durance, France, Laboratory for Plasma Physics, LPP-ERM/KMS, EUROfusion Consortium member, TEC Partner, Brussels, Belgium, Institute for Plasma Science and Technology, National Research Council, Milan, Italy, National Science Center Kharkiv Institute of Physics and Technology, 1 Akademichna Str., Kharkiv 61108, Ukraine, Jozef Stefan Institute [Ljubljana] (IJS), CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB, United Kingdom, Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20, Uppsala, Sweden, Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Physics and Astronomy, Uppsala University, and Uppsala University

Subjects
Plasma Physics (physics.plasm-ph), Physics::Plasma Physics, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Physics - Plasma Physics
Abstract

Megaelectron volt (MeV) alpha particles will be the main source of plasma heating in magnetic confinement fusion reactors. Yet, instead of heating fuel ions, most of the energy of alpha particles is transferred to electrons. Furthermore, alpha particles can also excite Alfvénic instabilities, previously considered as detrimental. Contrary to expectations, we demonstrate efficient ion heating in the presence of MeV ions and strong fast-ion driven Alfvénic instabilities in recent experiments on the Joint European Torus (JET). Detailed transport analysis of these experiments with state-of-the-art modeling tools explains the observations. Here we show a novel type of turbulence suppression and improved energy insulation in plasmas with MeV ions and fully developed Alfvénic activities through a complex multi-scale mechanism that generates large-scale zonal flows. This mechanism holds promise for a more economical operation of fusion reactors with dominant alpha particle heating and, ultimately, cheaper fusion electricity.

Published
2020
Full Text
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11. A quantitative comparison between confined fast ion data and models from radio frequency heating experiments with the three ion scenarios at JET

Author

Nocente, M., Kazakov, Ye O., Kiptily, V., Teddy CRACIUNESCU, Eriksson, J., Faustin, J., Giacomelli, L., Gorini, G., Hellesen, C., Lerche, E., Mantsinen, M., Ongena, J., Salewski, M., Sharapov, S., Tardocchi, M., Eester, D., JET Contributors, Coda, S, Berndt, J, Lapenta, G, Mantsinen, M, Michaut, C, Nocente, M, Kazakov, Y, Kiptily, V, Craciunescu, T, Eriksson, J, Faustin, J, Giacomelli, L, Gorini, G, Hellesen, C, Lerche, E, Ongena, J, Salewski, M, Sharapov, S, Tardocchi, M, and Van Eester, D

Subjects
3 ion scheme
Published
2018

12. Synergetic heating of D-NBI ions in the vicinity of the mode conversion layer in H-D plasmas in JET with the ITER like wall

Author

Ongena, J., Kazakov, Ye O., Baranov, Y., Hellesen, C., Eriksson, J., Johnson, T., Kiptily, V.G., Mantsinen, Mervi J., Nocente, M., Bilato, R., Cardinali, A., Castaldo, C., Crombé, K., Czarnecka, A., Dumont, R., Faustin, J., Giacomelli, L., Goloborodko, V., Graves, J., Jacquet, Ph., Krawczyk, N., Lerche, E., Meneses, L., Nave, M.F.F., Patten, H., Schneider, M., Van Eester, D., Weisen, H., Wright, J.C., JET Contributors, Barcelona Supercomputing Center, JET Contributors, Ongena, J, Kazakov, Y, Baranov, Y, Hellesen, C, Eriksson, J, Johnson, T, Kiptily, V, Mantsinen, M, Nocente, M, Bilato, R, Cardinali, A, Castaldo, C, Crombã©, K, Czarnecka, A, Dumont, R, Faustin, J, Giacomelli, L, Goloborodko, V, Graves, J, Jacquet, P, Krawczyk, N, Lerche, E, Meneses, L, Nave, M, Patten, H, Schneider, M, Van Eester, D, Weisen, H, and Wright, J

Subjects
Jet (fluid), Física [Àrees temàtiques de la UPC], Chemistry, Physics, QC1-999, RF power amplifier, Plasma heating, Resonance, Plasma, 01 natural sciences, Fusion research, Tècniques de plasma, 010305 fluids & plasmas, Ion, Acceleration, Physics and Astronomy (all), Physics and Astronomy, Physics::Plasma Physics, Electric field, 0103 physical sciences, Atomic physics, 010306 general physics, Beam (structure), Ion cyclotron range of frequencies
Abstract

This paper discusses the extension of the ‘three-ion’ species ICRF technique for heating mixture plasmas using fast injected NBI ions as resonant ‘third’ species. In this scenario the ICRF power is absorbed by the fast beam ions in the vicinity of the mode conversion layer where the left-hand polarized RF electric field E+ is strongly enhanced. The ions in the beam velocity distribution that have a Doppler-shifted resonance close to the mode conversion layer efficiently absorb RF power and undergo acceleration. We show first experimental observations of ICRF heating of D-NBI ions in H-D plasmas in JET with the ITER-like wall. In agreement with theoretical predictions and numerical modelling, acceleration of the D-NBI ions in this D-(DNBI)-H scenario is confirmed by several fast-ion measurements. An extension of the heating scheme discussed here is acceleration of T-NBI and D-NBI ions in D-T plasmas, offering the potential to further boost the Q-value in future D-T campaigns in JET. The support from the JET team is warmly acknowledged. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission and the ITER Organization.

Published
2017

13. Recent developments and physics prospects for ICRH on W7-X

Author

Ongena, J., Kazakov, Ye O., Borsuk, V., Durodié, F., Dirk Hartmann, Hollfeld, K. -P, Kallmeyer, J. P., Louche, F., Messiaen, A., Nicolai, D., Offermanns, G., Schweer, B., Stepanov, I., Vervier, M., Birus, D., Dinklage, A., Faustin, J., Krivska, A., Neubauer, O., Schoor, M., Wolf, R. C., and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Published
2017

14. Evidence for Alfven eigenmodes driven by alpha particles in D-He-3 fusion experiments on JET

Author

Kiptily, V. G., Fitzgerald, M., Kazakov, Ye. O., Ongena, J., Nocente, M., Sharapov, S. E., Dreval, M., Stancar, Z., Craciunescu, T., Garcia, J., Giacomelli, L., Goloborodko, V., Oliver, H. J. C., and Weisen, H.

Subjects
mhd instabilities, Physics::Plasma Physics, fast-ions, tokamak, fusion-born alpha-particles
Abstract

Alfven eigenmodes (AEs) driven by energetic alpha particles can lead to enhanced fast ion transport and losses, thereby degrading the plasma performance in ITER and future magnetic confinement fusion reactors. Unexpectedly, AEs with negative toroidal mode numbers, which are currently not considered for ITER, were observed in dedicated experiments with fusion-born alpha particles on the tokamak Joint European Torus (JET). The paper provides evidence for a complex interplay between fast ions, monster sawtooth crashes and AEs. Our results highlight the need for an improved description of the synergies between different fast ion phenomena in future burning plasmas.

17. Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating

Author

Kazakov, Ye. O., Ongena, J., Wright, J. C., Wukitch, S. J., Lerche, E., Mantsinen, M. J., Van Eester, D., Craciunescu, T., Kiptily, V. G., Lin, Y., Nocente, M., Nabais, F., Nave, M. F. F., Baranov, Y., Bielecki, J., Bilato, R., Bobkov, V., Crombe, K., Czarnecka, A., Faustin, J. M., Felton, R., Fitzgerald, M., Gallart, D., Giacomelli, L., Golfinopoulos, T., Hubbard, A. E., Jacquet, Ph., Johnson, T., Lennholm, M., Loarer, T., Porkolab, M., Sharapov, S. E., Valcarcel, D., Van Schoor, M., Weisen, H., JET Contributors, and Alcator C-Mod Team

Subjects
Physics::Plasma Physics, Physics::Space Physics
Abstract

We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed three-ion scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of He-3 ions to high energies in dedicated hydrogendeuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast He-3 ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, He-3-rich solar flares.

18. Technological and physics assessments on heating and current drive systems for DEMO

Author

Franke, Thomas, Barbato, E., Bosia, G., Cardinali, A., Ceccuzzi, S., Cesario, R., Van Eester, D., Federici, G., Gantenbein, G., Helou, W., Hillairet, J., Jenkins, I., Kazakov, Ye. O., Kemp, R., Lerche, E., Mirizzi, F., Noterdaeme, J. -M., Poli, E., Porte, L., Ravera, G. L., Surrey, E., Tardini, G., Tran, M. Q., Tsironis, C., Tuccillo, A. A., Wenninger, R., Zohm, H., and EFDA PPP&T Team

Subjects
Electron cyclotron, DEMO, Heating & Current Drive, Ion cyclotron, Lower hybrid, Neutral beam
Abstract

The physics requirements of the heating and current (H&CD) systems in a Demonstration Fusion Power Plant (DEMO) are often beyond the actual level of design maturity and technology readiness required. The recent EU fusion roadmap advocates a pragmatic approach and favours, for the initial design integration studies, systems to be as much as possible, extrapolated from the ITER experience. To reach the goal of demonstrating the production of electricity in DEMO with a closed fuel cycle by 2050, one must ensure reliability, availability, maintainability, inspectability (RAMI) as well as performance, efficiency and optimized design for the H&CD systems. In the recent Power Plant Physics & Technology (PPP&T) Work Programme, a number of H&CD studies were performed. The four H&CD systems Neutral Beam (NB) Injection, Electron Cyclotron (EC), Ion Cyclotron (IC) and Lower Hybrid (LH) were considered. First, a physics optimization study was made assuming all technologies are available and identifying which parameters are needed to optimize the performance for given plasma parameters. Separately, the (i) technological maturity was considered (e.g. 240 GHz gyrotrons for EC) and (ii) technologies were adapted (e.g. multi-stage depressed collector for EC) or (iii) novel solutions (e.g. photo-neutralization for NB or new antennae concepts for IC) were studied to overcome the limitations of the present H&CD systems with respect to DEMO requirements. Further constraints imposed by remote maintenance or breeding blanket interactions were considered. (C) 2015 Max-Planck-Institute for Plasma Physics. Published by Elsevier B.V. All rights reserved.

19. Modelling of three-ion ICRF schemes with PION

Author

Mantsinen, M. J., Kazakov, Ye O., Bobkov, V., Teddy CRACIUNESCU, Gallart, D., Giacomelli, L., Kappatou, A., Nocente, M., Weiland, M., JET Contributors, EUROfusion MST1 Team, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Riconda, C, Brezinsek, S, McCarty, K, Lancaster, K, Burgess, D, Brault, P, Mantsinen, M, Kazakov, Y, Bobkov, V, Craciunescu, T, Gallart, D, Giacomelli, L, Kappatou, A, Nocente, M, and Weiland, M

Subjects
ICRF

20. Analysis of metallic impurities during the application of three-ion ICRH scenario at JET-ILW

Author

A. Chomiczewska, J. Ongena, D. Van Eester, Jet Contributors, Ye. O. Kazakov, V. Bobkov, N. Krawczyk, E. Kowalska-Strzęciwilk, M. J. Mantsinen, E. Lerche, Th. Pütterich, G. Pucella, JET Contributors, Chomiczewska, A., Krawczyk, N., Kazakov, Ye. O., Bobkov, V., Kowalska-Strzeciwilk, E., Lerche, E., Mantsinen, M. J., Ongena, J., Pucella, G., Putterich, T., and Van Eester, D.

Subjects
Materials science, Cyclotron resonance, Plasma, Effective radiated power, 01 natural sciences, Effective nuclear charge, 010305 fluids & plasmas, Ion, Magnetic field, Dipole, Impurity, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

The effect of the novel ‘three-ion’ D-(3He)-H minority ICRH heating scheme on the behavior of the metallic impurities at JET-ILW is discussed. The reported experiment was performed in L-mode plasmas at a magnetic field BT = 3.2 T, plasma current Ip = 2 MA and central plasma densities ne(0) ≈ 4×1019 m-3. ICRH power was delivered with dipole or +π/2 antenna phasing at f ≈ 32.2-33MHz, placing the 3He cyclotron resonance at the plasma core. The edge isotopic ratio H/(H+D) was varied between 73 and 92%, and 3He concentration in the range of 0.1-1.5% to assess the sensitivity of the scheme to the detailed plasma composition. The results of our analysis show a linear increase of the plasma effective charge Zeff, radiated power Prad,bulk and content of metallic impurities with ICRF power. The observed scattering of the points reflects the difference in the plasma composition and ICRF antenna phasing. For discharges heated with similar ICRH power level ~4MW, our analysis indicates that for a large range of H/(H+D) the novel scenario effectively heats the plasma with reduced content of metallic impurities. The impurities are shown to be concentrated mainly around the mid-radius region of the plasma. We conclude this paper with a discussion of the effect of the long-period sawteeth on the observed dynamics of metallic impurities in the plasma core.

Published
2020

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