Investigation of double frequency fishbone in EAST with neutral beam injection
In the EAST experiments with neutral beam injection and at a low electron density, fishbone instabilities characterized by mode numbers m / n = 1/1, 2/2 have been observed. The simultaneous growth of these modes, particularly m / n = 1/1 and m / n = 2/2, results in a decrease in neutron emission at...
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IOP Publishing
2025-01-01
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| Series: | Nuclear Fusion |
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| Online Access: | https://doi.org/10.1088/1741-4326/add359 |
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| author | Wei Shen Liqing Xu Zhiyong Qiu Yan Chao Yifeng Wang Yuqi Chu Jianwen Liu Baolong Hao Ming Xu Yinfei Jin Guoqiang Zhong Zhihong Kuang Shengfa Wu the EAST Team |
| author_facet | Wei Shen Liqing Xu Zhiyong Qiu Yan Chao Yifeng Wang Yuqi Chu Jianwen Liu Baolong Hao Ming Xu Yinfei Jin Guoqiang Zhong Zhihong Kuang Shengfa Wu the EAST Team |
| author_sort | Wei Shen |
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| description | In the EAST experiments with neutral beam injection and at a low electron density, fishbone instabilities characterized by mode numbers m / n = 1/1, 2/2 have been observed. The simultaneous growth of these modes, particularly m / n = 1/1 and m / n = 2/2, results in a decrease in neutron emission at the plasma core. As the electron density continues to decrease, the beta-induced Alfvén eigenmode (BAE) emerges, replacing the m / n = 2/2 fishbone just before a more severe sawtooth crash occurs. Numerical simulations with the global kinetic-magnetohydrodynamic (MHD) code M3D-K show that the m / n = 2/2 high frequency fishbone branch is linearly stable, but nonlinearly grows due to the coupling with the m / n = 1/1 low frequency fishbone branch. The m / n = 2/2 fishbone frequency is almost twice of the m / n = 1/1 fishbone, and both fishbone frequencies chirp down together. The mode frequencies and structures of the simulated fishbones are consistent with the experimental measurements. In addition, a BAE with m / n = 2/2 is observed in the late nonlinear stage of the simulation. Energetic particle nonlinearity is dominant for the m / n = 2/2 fishbone saturation and transition to BAE. In particular, the transition from m / n = 2/2 fishbone to BAE is found to be the consequence of fast ion redistribution due to the fishbone instability. |
| format | Article |
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| institution | Kabale University |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | Nuclear Fusion |
| spelling | doaj-art-2d09462c407a4474a89a1ce597956f6e2025-08-20T03:52:57ZengIOP PublishingNuclear Fusion0029-55152025-01-0165606601210.1088/1741-4326/add359Investigation of double frequency fishbone in EAST with neutral beam injectionWei Shen0https://orcid.org/0000-0003-3453-0619Liqing Xu1https://orcid.org/0009-0003-7340-1083Zhiyong Qiu2https://orcid.org/0000-0002-7548-8819Yan Chao3Yifeng Wang4https://orcid.org/0000-0002-0368-9566Yuqi Chu5https://orcid.org/0000-0002-7379-0117Jianwen Liu6Baolong Hao7https://orcid.org/0000-0003-3009-0660Ming Xu8https://orcid.org/0000-0002-5142-4474Yinfei Jin9https://orcid.org/0000-0002-3061-6709Guoqiang Zhong10https://orcid.org/0000-0002-6235-933XZhihong Kuang11Shengfa Wu12the EAST TeamInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaCollege of Physics and Optoelectronic Engineering, Shenzhen University , Shenzhen 518060, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaSouthwestern Institute of Physics , Chengdu 610041, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Science , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaIn the EAST experiments with neutral beam injection and at a low electron density, fishbone instabilities characterized by mode numbers m / n = 1/1, 2/2 have been observed. The simultaneous growth of these modes, particularly m / n = 1/1 and m / n = 2/2, results in a decrease in neutron emission at the plasma core. As the electron density continues to decrease, the beta-induced Alfvén eigenmode (BAE) emerges, replacing the m / n = 2/2 fishbone just before a more severe sawtooth crash occurs. Numerical simulations with the global kinetic-magnetohydrodynamic (MHD) code M3D-K show that the m / n = 2/2 high frequency fishbone branch is linearly stable, but nonlinearly grows due to the coupling with the m / n = 1/1 low frequency fishbone branch. The m / n = 2/2 fishbone frequency is almost twice of the m / n = 1/1 fishbone, and both fishbone frequencies chirp down together. The mode frequencies and structures of the simulated fishbones are consistent with the experimental measurements. In addition, a BAE with m / n = 2/2 is observed in the late nonlinear stage of the simulation. Energetic particle nonlinearity is dominant for the m / n = 2/2 fishbone saturation and transition to BAE. In particular, the transition from m / n = 2/2 fishbone to BAE is found to be the consequence of fast ion redistribution due to the fishbone instability.https://doi.org/10.1088/1741-4326/add359fishboneenergetic particleEASTfrequency chirpingwave- particle resonance |
| spellingShingle | Wei Shen Liqing Xu Zhiyong Qiu Yan Chao Yifeng Wang Yuqi Chu Jianwen Liu Baolong Hao Ming Xu Yinfei Jin Guoqiang Zhong Zhihong Kuang Shengfa Wu the EAST Team Investigation of double frequency fishbone in EAST with neutral beam injection Nuclear Fusion fishbone energetic particle EAST frequency chirping wave- particle resonance |
| title | Investigation of double frequency fishbone in EAST with neutral beam injection |
| title_full | Investigation of double frequency fishbone in EAST with neutral beam injection |
| title_fullStr | Investigation of double frequency fishbone in EAST with neutral beam injection |
| title_full_unstemmed | Investigation of double frequency fishbone in EAST with neutral beam injection |
| title_short | Investigation of double frequency fishbone in EAST with neutral beam injection |
| title_sort | investigation of double frequency fishbone in east with neutral beam injection |
| topic | fishbone energetic particle EAST frequency chirping wave- particle resonance |
| url | https://doi.org/10.1088/1741-4326/add359 |
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