Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generation
The plasma in future nuclear fusion reactors will be heated by neutral beam injectors (NBIs) and high frequency electromagnetic waves as well as fusion born alpha particles. Energetic particles (EPs), with energies up to two orders of magnitude larger than the thermal plasma, can trigger EP driven m...
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| author | J. Varela J. Garcia S. Mazzi Y. Kazakov Z. Stancar M. Baruzzo J. Ongena D.A. Spong L. Garcia Y. Ghai D. Zarzoso J. Ortiz M. Poradzinski S. Sharapov M. Fitzgerald B. Breizman F. Waelbroeck S. Menmuir H.J. Sun D. Kos A. Boboc N.C. Hawkes JET Contributors the EUROfusion Tokamak Exploitation team |
| author_facet | J. Varela J. Garcia S. Mazzi Y. Kazakov Z. Stancar M. Baruzzo J. Ongena D.A. Spong L. Garcia Y. Ghai D. Zarzoso J. Ortiz M. Poradzinski S. Sharapov M. Fitzgerald B. Breizman F. Waelbroeck S. Menmuir H.J. Sun D. Kos A. Boboc N.C. Hawkes JET Contributors the EUROfusion Tokamak Exploitation team |
| author_sort | J. Varela |
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| description | The plasma in future nuclear fusion reactors will be heated by neutral beam injectors (NBIs) and high frequency electromagnetic waves as well as fusion born alpha particles. Energetic particles (EPs), with energies up to two orders of magnitude larger than the thermal plasma, can trigger EP driven modes and induce harmful EP losses, reducing the plasma heating efficiency and the economical viability of the reactor. The present study is dedicated to analyze the Alfven Eigenmode (AE) activity in JET D–T discharges, the closest experiment to reactor-like operation performed until now. There, EP driven modes are induced by the combined effect of tangential NBIs and ion cyclotron resonance heating (ICRH) driven EP. Linear and nonlinear simulations are performed with the gyro-fluid FAR3d code to analyze the AE activity observed in the discharge 99896. The linear simulations reproduce the unstable n = 3 to 5 toroidal AEs (TAE) at the inner plasma region observed in the experiment, triggered by highly energetic passing deuterium populations injected by the tangential NBIs, further accelerated by the effect of the ICRH up to 1 MeV. In addition, fish-bones triggered by energetic trapped hydrogen induced by the ICRH are also reproduced. On the other hand, the alpha particles density is too small to destabilize AEs in the experiment. Nonetheless, increasing artificially the alpha density by one order of magnitude, an n = 1 beta induced AE can be destabilized in the inner plasma region. Nonlinear simulations indicate the generation of zonal structures during the AE/fish-bone saturation phase. TAE and fish-bones causes a rather weak increase of the passing D and trapped H EP (around 2%), respectively. Shear flows and zonal currents are generated during the saturation of TAE and fish-bones. Nonlinear simulations performed for D–T and pure deuterium thermal plasma indicate AE/fish-bone activity is weaker and shear flows are less intense in the pure deuterium case, trends consistent with the experimental observations that also indicates a deterioration of the thermal plasma confinement. Therefore, both numerical studies and experimental evidence indicate the generation of shear flows by AE/fish-bones could be connected with an improvement of the thermal plasma confinement. |
| format | Article |
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| spelling | doaj-art-45711276b79746a0a22dbf18c4247ead2025-08-20T02:35:05ZengIOP PublishingNuclear Fusion0029-55152025-01-0165707604410.1088/1741-4326/ade696Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generationJ. Varela0https://orcid.org/0000-0002-6114-0539J. Garcia1https://orcid.org/0000-0003-0900-5564S. Mazzi2https://orcid.org/0000-0001-6491-8759Y. Kazakov3https://orcid.org/0000-0001-6316-5441Z. Stancar4https://orcid.org/0000-0002-9608-280XM. Baruzzo5J. Ongena6https://orcid.org/0000-0001-7456-4739D.A. Spong7https://orcid.org/0000-0003-2370-1873L. Garcia8https://orcid.org/0000-0002-0492-7466Y. Ghai9https://orcid.org/0000-0002-8432-0233D. Zarzoso10https://orcid.org/0000-0002-7220-8092J. Ortiz11https://orcid.org/0000-0003-1027-8244M. Poradzinski12https://orcid.org/0000-0002-1858-4046S. Sharapov13https://orcid.org/0000-0001-7006-4876M. Fitzgerald14B. Breizman15https://orcid.org/0000-0002-7908-6497F. Waelbroeck16https://orcid.org/0000-0001-9324-3690S. Menmuir17H.J. Sun18https://orcid.org/0000-0003-0880-0013D. Kos19A. Boboc20https://orcid.org/0000-0001-8841-3309N.C. Hawkes21JET Contributorsthe EUROfusion Tokamak Exploitation teamInstitute for Fusion Studies, Department of Physics, University of Texas at Austin , Austin, TX 78712, United States of America; Universidad Carlos III de Madrid , 28911 Leganes, Madrid, SpainCEA, IRFM , F-13108 Saint Paul-lez-Durance, FranceCEA, IRFM , F-13108 Saint Paul-lez-Durance, FranceLaboratory for Plasma Physics, LPP-ERM/KMS, TEC Partner , 1000 Brussels, BelgiumUnited Kingdom Atomic Energy Authority, Culham Science Centre , Abingdon, United Kingdom of Great Britain and Northern IrelandConsorzio RFX , Corso Stati Uniti 4, Padova, Italy; ENEA for EUROfusion , Via E. Fermi 45, 00044 Frascati (Roma), ItalyPlasma Physics Laboratory—Royal Military Academy , Renaissancelaan 30, 1000 Brussels, BelgiumOak Ridge National Laboratory , Oak Ridge, TN 37831-8071, United States of AmericaUniversidad Carlos III de Madrid , 28911 Leganes, Madrid, SpainOak Ridge National Laboratory , Oak Ridge, TN 37831-8071, United States of AmericaAix Marseille Univ, CNRS , Centrale Med, M2P2 Marseille, FranceUniversidad Carlos III de Madrid , 28911 Leganes, Madrid, SpainInstitute of Plasma Physics and Laser Microfusion , Hery str. 23, 01-497 Warsaw, PolandUKAEA, Culham Science Centre , Abingdon, Oxfordshire OX14 3DB, United Kingdom of Great Britain and Northern IrelandUKAEA, Culham Science Centre , Abingdon, Oxfordshire OX14 3DB, United Kingdom of Great Britain and Northern IrelandInstitute for Fusion Studies, Department of Physics, University of Texas at Austin , Austin, TX 78712, United States of AmericaInstitute for Fusion Studies, Department of Physics, University of Texas at Austin , Austin, TX 78712, United States of AmericaUKAEA, Culham Science Centre , Abingdon, Oxfordshire OX14 3DB, United Kingdom of Great Britain and Northern IrelandUKAEA, Culham Science Centre , Abingdon, Oxfordshire OX14 3DB, United Kingdom of Great Britain and Northern IrelandUKAEA, Culham Science Centre , Abingdon, Oxfordshire OX14 3DB, United Kingdom of Great Britain and Northern IrelandUKAEA, Culham Science Centre , Abingdon, Oxfordshire OX14 3DB, United Kingdom of Great Britain and Northern IrelandUKAEA, Culham Science Centre , Abingdon, Oxfordshire OX14 3DB, United Kingdom of Great Britain and Northern IrelandThe plasma in future nuclear fusion reactors will be heated by neutral beam injectors (NBIs) and high frequency electromagnetic waves as well as fusion born alpha particles. Energetic particles (EPs), with energies up to two orders of magnitude larger than the thermal plasma, can trigger EP driven modes and induce harmful EP losses, reducing the plasma heating efficiency and the economical viability of the reactor. The present study is dedicated to analyze the Alfven Eigenmode (AE) activity in JET D–T discharges, the closest experiment to reactor-like operation performed until now. There, EP driven modes are induced by the combined effect of tangential NBIs and ion cyclotron resonance heating (ICRH) driven EP. Linear and nonlinear simulations are performed with the gyro-fluid FAR3d code to analyze the AE activity observed in the discharge 99896. The linear simulations reproduce the unstable n = 3 to 5 toroidal AEs (TAE) at the inner plasma region observed in the experiment, triggered by highly energetic passing deuterium populations injected by the tangential NBIs, further accelerated by the effect of the ICRH up to 1 MeV. In addition, fish-bones triggered by energetic trapped hydrogen induced by the ICRH are also reproduced. On the other hand, the alpha particles density is too small to destabilize AEs in the experiment. Nonetheless, increasing artificially the alpha density by one order of magnitude, an n = 1 beta induced AE can be destabilized in the inner plasma region. Nonlinear simulations indicate the generation of zonal structures during the AE/fish-bone saturation phase. TAE and fish-bones causes a rather weak increase of the passing D and trapped H EP (around 2%), respectively. Shear flows and zonal currents are generated during the saturation of TAE and fish-bones. Nonlinear simulations performed for D–T and pure deuterium thermal plasma indicate AE/fish-bone activity is weaker and shear flows are less intense in the pure deuterium case, trends consistent with the experimental observations that also indicates a deterioration of the thermal plasma confinement. Therefore, both numerical studies and experimental evidence indicate the generation of shear flows by AE/fish-bones could be connected with an improvement of the thermal plasma confinement.https://doi.org/10.1088/1741-4326/ade696tokamakJETMHDAEfish-bones and shear flows |
| spellingShingle | J. Varela J. Garcia S. Mazzi Y. Kazakov Z. Stancar M. Baruzzo J. Ongena D.A. Spong L. Garcia Y. Ghai D. Zarzoso J. Ortiz M. Poradzinski S. Sharapov M. Fitzgerald B. Breizman F. Waelbroeck S. Menmuir H.J. Sun D. Kos A. Boboc N.C. Hawkes JET Contributors the EUROfusion Tokamak Exploitation team Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generation Nuclear Fusion tokamak JET MHD AE fish-bones and shear flows |
| title | Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generation |
| title_full | Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generation |
| title_fullStr | Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generation |
| title_full_unstemmed | Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generation |
| title_short | Analysis of the linear and nonlinear stability of Alfven eigenmodes and fish-bones in JET DT discharges: mode identification and shear flows generation |
| title_sort | analysis of the linear and nonlinear stability of alfven eigenmodes and fish bones in jet dt discharges mode identification and shear flows generation |
| topic | tokamak JET MHD AE fish-bones and shear flows |
| url | https://doi.org/10.1088/1741-4326/ade696 |
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