Variational symplectic particle-in-cell simulation of nonlinear mode conversion from extraordinary waves to Bernstein waves
Variational symplectic particle-in-cell simulation of nonlinear mode conversion from extraordinary waves to Bernstein waves
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DOI：
10.1063/1.4930118
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发表时间：
2015-06
影响因子：
2.2
通讯作者：
Jianyuan Xiao;Jian Liu;H. Qin;Zhi Yu;N. Xiang
中科院分区：
文献类型：
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作者：
Jianyuan Xiao;Jian Liu;H. Qin;Zhi Yu;N. Xiang
本文采用变分辛粒子-胞内模拟方法研究了非均匀磁化等离子体中异常波的非线性模式转换。辛算法的长期精度和保守性保证了非线性仿真的准确性。研究了非线性模式转换过程中电磁波的波谱、反射率的演变、能量沉积分布以及射频波的参数依赖特性。结果表明，非线性效应显著地改变了磁化等离子体中射频注入的物理特性。观察了射频波反射率和能量沉积的演变，以及伯恩斯坦波和模态激励的自相互作用。在实际的射频波加热和电流驱动实验中，即使对于较小的波，连续波注入后的非线性效应也会变得很重要。
In this paper, the nonlinear mode conversion of extraordinary waves in nonuniform magnetized plasmas is studied using the variational symplectic particle-in-cell simulation. The accuracy of the nonlinear simulation is guaranteed by the long-term accuracy and conservativeness of the symplectic algorithm. The spectra of the electromagnetic wave, the evolution of the wave reflectivity, the energy deposition profile, and the parameter-dependent properties of radio-frequency waves during the nonlinear mode conversion are investigated. It is illustrated that nonlinear effects significantly modify the physics of the radio-frequency injection in magnetized plasmas. The evolutions of the radio-frequency wave reflectivity and the energy deposition are observed, as well as the self-interaction of the Bernstein waves and mode excitations. Even for waves with small magnitude, nonlinear effects can also become important after continuous wave injections, which are common in the realistic radio-frequency wave heating and current drive experiments.