Dynamic evolutions of multiple toroidal Alfvén eigenmodes with energetic particles
Dynamic evolutions of multiple toroidal Alfvén eigenmodes with energetic particles
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DOI：
10.1063/1.4859175
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发表时间：
2013-12
影响因子：
2.2
通讯作者：
J. Zhu;Zhiwei Ma;G. Fu
中科院分区：
文献类型：
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作者：
J. Zhu;Zhiwei Ma;G. Fu
基于一个简化模型，对高能粒子驱动下多个环形诱导剪切Alfven本征模的动态演化进行了动力学模拟。结果表明，通过粒子和俘获粒子对模的演化起着不同的作用。对于没有背景阻尼的情况下，通过粒子导致一个较长的线性增长阶段和随后的增强的非线性饱和度时，两个模式的谐振区域紧密重叠。另一方面，捕获粒子是主要负责的非线性阶段的持续模式的增长。通过比较各向异性和各向同性模拟的结果，它表明，通过粒子的非线性阶段的模式发展有负面影响。对于背景阻尼较大的近边缘稳定性情况，由于分布函数中孔洞和团块的重叠，多个分支中的向上和向下频率啁啾受到多模相互作用的显着影响。
Kinetic simulations based on a reduced model are carried out to study dynamic evolutions of multiple toroidicity-induced shear Alfven eigenmodes driven by energetic particles. It is found that passing and trapped particles play quite different roles on the mode evolution. For cases without background damping, passing particles lead to a longer linear growth phase and subsequent enhancement of the nonlinear saturation level when resonant regions with two modes are closely overlapped. On the other hand, trapped particles are mainly responsible for the persistent mode growth in the nonlinear phase. By comparing the results from anisotropic and isotropic simulations, it is suggested that passing particles have a negative impact on the mode development in the nonlinear phase. For the near marginal stability cases with large background damping, the upward and downward frequency chirping in multiple branches are significantly affected by the multi-mode interaction due to overlapping of hole and clump in the distribution function.