Observation of multiple beta-induced Alfvén eigenmodes driven by runaway electrons in EAST Ohmic discharge

Abstract Multiple Beta-induced Alfvén eigenmodes (BAEs) excited by runaway electrons (REs) have been observed in low-density Ohmic discharges in the EAST tokamak. The toroidal mode number is mainly n = −1 and they rotate in the electron diamagnetic drift direction. These modes in the low frequency range from 10 to 25 kHz, are found to be unstable when the electron density decreases to less than 0.65 × 10 19 m −3 . BAEs depend sensitively on the RE current fraction. By decreasing electron density, the resistive current is replaced by that carried by the REs. Then more branches of unstable BAEs, which located at different rational surfaces, are simultaneously observed, indicating that BAEs depend sensitively on the plasma beta contributed from REs. Simulation results provided by the global eigenvalue code magnetohydrodynamic Alfvén spectra suggest trapped energetic particles are responsible for the destabilization of these BAEs, which match the resonance condition and the mode locations are close to the plasma boundary.

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Publication Details

Journal
Nuclear Fusion
Published
2025-06-03
DOI
https://doi.org/10.1088/1741-4326/addfeb
Citations
1
Primary Topic
Ionosphere and magnetosphere dynamics
Type
article
Field-Weighted Citation Impact
1.15

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article

Observation of multiple beta-induced Alfvén eigenmodes driven by runaway electrons in EAST Ohmic discharge

J.P. Qian, Ruirui Ma, Zhiyong Qiu, Tonghui Shi et al.
1 citations
Nuclear Fusion
Ionosphere and magnetosphere dynamics
1.15
article

Observation of multiple beta-induced Alfvén eigenmodes driven by runaway electrons in EAST Ohmic discharge

J.P. Qian, Ruirui Ma, Zhiyong Qiu, Tonghui Shi, Xiang Gao, Xiang Zhu, Long Zeng, Tian Tang, Shiyao Lin, Y. Liang, Jian Bao, Chun Xia Luo, Haiqing Liu
article en
1 citations

Abstract

Abstract Multiple Beta-induced Alfvén eigenmodes (BAEs) excited by runaway electrons (REs) have been observed in low-density Ohmic discharges in the EAST tokamak. The toroidal mode number is mainly n = −1 and they rotate in the electron diamagnetic drift direction. These modes in the low frequency range from 10 to 25 kHz, are found to be unstable when the electron density decreases to less than 0.65 × 10 19 m −3 . BAEs depend sensitively on the RE current fraction. By decreasing electron density, the resistive current is replaced by that carried by the REs. Then more branches of unstable BAEs, which located at different rational surfaces, are simultaneously observed, indicating that BAEs depend sensitively on the plasma beta contributed from REs. Simulation results provided by the global eigenvalue code magnetohydrodynamic Alfvén spectra suggest trapped energetic particles are responsible for the destabilization of these BAEs, which match the resonance condition and the mode locations are close to the plasma boundary.

Nuclear FusionVol. 65(7)
University of Science and Technology of China (CN), Forschungszentrum Jülich (DE), Shenzhen University (CN), Hefei Institutes of Physical Science (CN), Institute of Plasma Physics (CN), Institute of Physics (CN), Southwestern Institute of Physics (CN), Tsinghua University (CN)
National Natural Science Foundation of China, National Key Research and Development Program of China
Openalex Percentile: Top 19%
Ionosphere and magnetosphere dynamics
1.15
DOIOpen Access PDFOpenAlex
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