Nonlinear dynamics of beta-induced Alfven eigenmode in tokamak
- Fusion Simulation Center, Peking University, Beijing 100871 (China)
- Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)
- Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)
- CAS Key Laboratory of Plasma Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)
The beta-induced Alfven eigenmode (BAE) excited by energetic particles in toroidal plasmas is studied in the global gyrokinetic simulations. It is found that the nonlinear BAE dynamics depends on the deviation from the marginality. In the strongly driven case, the mode exhibits a bursting state with fast and repetitive chirping. The nonlinear saturation is determined by the thermal ion nonlinearity and has no clear dependence on the linear growth rate. In the weakly driven case, the mode reaches a nearly steady state with small frequency chirping. The nonlinear dynamics is dominated by the energetic particle nonlinearity. In both cases, the nonlinear intensity oscillation and frequency chirping are correlated with the evolution of the coherent structures in the energetic particle phase space. Due to the radial variation of the mode amplitude and the radially asymmetric guiding center dynamics, the wave-particle interaction in the toroidal geometry is much more complex than the conventional one-dimensional wave-particle interaction paradigm.
- OSTI ID:
- 22113356
- Journal Information:
- Physics of Plasmas, Vol. 20, Issue 1; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Observation of tungsten impurities induced 2/1 snake fluctuations and their interactions with discrete double BAE pairs on EAST
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journal | November 2018 |
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