Simulation study of the harmonic structure of lower hybrid waves driven by energetic ions.
Simulation study of the harmonic structure of lower hybrid waves driven by energetic ions.
复制标题
DOI：
10.1103/physreve.108.035208
复制
发表时间：
2023-09
期刊：
影响因子：
--
通讯作者：
T. Kotani;M. Toida;T. Moritaka;Satoshi Taguchi
中科院分区：
文献类型：
--
作者：
T. Kotani;M. Toida;T. Moritaka;Satoshi Taguchi
通过考虑能量离子注入效应的一维电磁粒子模拟，研究了在电子等离子体频率（ω_{pe}）小于电子回旋频率（Ω_{e}）的情况下，高能离子驱动的低杂化波（LHWs）的谐波结构。研究发现，以波数和频率（k_{1},ω_{1}）激发LHWs后，在m和n为整数的（mk_{1},nω_{1}）处产生了许多谐波LHWs，远超过混合共振的较低频率m和n ~ 10。结果表明，谐波强子黑洞是由高能离子直接激发的强子黑洞与较低混合共振频率以上的能量离子回旋波之间的非线性波-波耦合产生的。我们还发现，即使人工去除高能离子，谐波大黑洞仍然存在，因为它们可以与体离子引起的离子伯恩斯坦波耦合。研究了能量离子注入和ω_{pe}/Ω_{e}对谐波强子波发展的影响，并将模拟结果与地球磁层观测结果进行了比较。
By means of one-dimensional, electromagnetic, particle-in-cell simulations considering the effects of energetic-ion injection, we study the harmonic structure of lower hybrid waves (LHWs) driven by energetic ions under the condition where the electron plasma frequency (ω_{pe}) is smaller than the electron cyclotron frequency (Ω_{e}). It is found that after the LHWs are excited with the wave number and frequency of (k_{1},ω_{1}), many harmonic LHWs are generated at (mk_{1},nω_{1}) where m and n are integers, up to far beyond the lower hybrid resonance frequency, m and n∼10. We show that the harmonic LHWs are generated by nonlinear wave-wave coupling between the LHWs directly excited by the energetic ions and the energetic-ion cyclotron waves above the lower hybrid resonance frequency. We also find that the harmonic LHWs can exist even after the energetic ions are artificially removed because they can be coupled with ion Bernstein waves due to bulk ions. The effect of the energetic-ion injection and the dependence of ω_{pe}/Ω_{e} on the development of the harmonic LHWs are investigated to compare the simulation results with an observation in Earth's magnetosphere.