A new excitation mechanism of He+ band electromagnetic ion cyclotron wave: Hybrid simulation study
A new excitation mechanism of He+ band electromagnetic ion cyclotron wave: Hybrid simulation study
复制标题
He带电磁离子回旋波激发新机制：混合模拟研究
DOI：
10.1063/5.0030265
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Sun Jicheng
中科院分区：
文献类型：
--
作者：
Yao Jiansheng;Zhao YinKui;Li Yi;Chai Lihui;Sun Jicheng
提出了一种新的He ~+波段电磁离子回旋波的激发机制。通过一维混合模拟，我们发现各向异性热H+激发的H+带EMIC波的频率在初始阶段迅速下降，然后激发出一个窄的He+带EMIC波。同时，离子的温度也发生了显著的变化。用线性动力学理论证明了温度变化不能激发He ~+带的EMIC波。混合模拟结果表明，在这一过程中，He+的分布发生了变化，为X型。进一步的研究证实了X型分布的He+可能是由H+带EMIC波的俯仰角散射激发的He+带EMIC波引起的。进一步的研究表明，激发He ~+带EMIC波的自由能来自高能He ~+，具有X型分布的蝶翼形部分
A new excitation mechanism of the He+ band electromagnetic ion cyclotron (EMIC) wave is proposed in this paper. Through 1D hybrid simulation, we find that the frequency of the H+ band EMIC wave triggered by anisotropic hot H+ drops quickly in the initial stage, and then, a narrow He+ band EMIC wave is excited. Meanwhile, the temperature of ions also changes significantly. Using the linear kinetic theory, we have proved that the temperature variance cannot stimulate the He+ band EMIC wave. Hybrid simulation results show that the distribution of He+ is changed to be X-type during this process. Further investigation confirms that X-type distributed He+ may be caused via the pitch angle scattering by the H+ band EMIC wave, which stimulates the He+ band EMIC wave. Beyond that, further research shows that the free energy to excite the He+ band EMIC wave comes from higher energy He+ with a butterfly wing shaped part of X type distribution