Nonlinear simulation of multiple toroidal Alfven eigenmodes in tokamak plasmas*
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论文类型：期刊论文
发表时间：2020-02-01
发表刊物：CHINESE PHYSICS B
收录刊物：EI、SCIE
卷号：29
期号：2
ISSN号：1674-1056
关键字：tokamak; toroidal Alfven eigenmode; wave-particle interaction; beam ion loss
摘要：Nonlinear evolution of multiple toroidal Alfven eigenmodes (TAEs) driven by fast ions is self-consistently investigated by kinetic simulations in toroidal plasmas. To clearly identify the effect of nonlinear coupling on the beam ion loss, simulations over single-n modes are also carried out and compared with those over multiple-n modes, and the wave-particle resonance and particle trajectory of lost ions in phase space are analyzed in detail. It is found that in the multiple-n case, the resonance overlap occurs so that the fast ion loss level is rather higher than the sum loss level that represents the summation of loss over all single-n modes in the single-n case. Moreover, increasing fast ion beta beta(h) can not only significantly increase the loss level in the multiple-n case but also significantly increase the loss level increment between the single-n and multiple-n cases. For example, the loss level in the multiple-n case for beta(h) = 6.0% can even reach 13% of the beam ions and is 44% higher than the sum loss level calculated from all individual single-n modes in the single-n case. On the other hand, when the closely spaced resonance overlap occurs in the multiple-n case, the release of mode energy is increased so that the widely spaced resonances can also take place. In addition, phase space characterization is obtained in both single-n and multiple-n cases.
发表时间：2020-02-01