Particle-in-cell simulations – ion beam instabilities and the generation of Alfvén and whistler waves in low β plasma
Particle-in-cell simulations – ion beam instabilities and the generation of Alfvén and whistler waves in low β plasma
复制标题
细胞内粒子模拟 – 离子束不稳定性以及低 β 等离子体中阿尔芬波和哨声波的产生
DOI：
10.1093/mnras/stad2897
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发表时间：
2023
影响因子：
4.8
通讯作者：
Zank, G P
中科院分区：
文献类型：
--
作者：
Che, H;Benz, A O;Zank, G P
采用粒子模拟方法研究了低β（即低等离子体和磁压比）无碰撞空间等离子体中离子束驱动的不稳定性。具体而言，不同的离子漂移速度的布尼曼和共振电磁（EM）右手（RH）离子束不稳定性的发展的影响进行了研究。我们的模拟结果表明，这两种不稳定性可以驱动时，离子束漂移超过理论阈值。布尼曼不稳定性，这是弱触发最初，耗散只有一小部分的离子束的动能，同时导致显着的电子加热，由于小的电子-离子质量比。然而，我们发现，离子束驱动的布曼不稳定性有效地淬火共振EM RH离子束不稳定性。相反，当离子漂移速度大于阿尔文速度时，共振EM RH离子束不稳定性占主导地位，导致RH阿尔文波和RH哨声波的产生。结果表明，随着离子束漂移速度的减小，Alfvén波的强度减小，而哨声波的强度增大。我们的研究结果为低β无碰撞空间等离子体中离子束和等离子体不稳定性之间复杂的相互作用提供了新的见解。
Ion beam-driven instabilities in a collisionless space plasma with low β, i.e. low plasma and magnetic pressure ratio, are investigated using particle-in-cell (PIC) simulations. Specifically, the effects of different ion drift velocities on the development of Buneman and resonant electromagnetic (EM) right-handed (RH) ion beam instabilities are studied. Our simulations reveal that both instabilities can be driven when the ion beam drift exceeds the theoretical thresholds. The Buneman instability, which is weakly triggered initially, dissipates only a small fraction of the kinetic energy of the ion beam while causing significant electron heating, owing to the small electron-ion mass ratio. However, we find that the ion beam-driven Buneman instability is quenched effectively by the resonant EM RH ion beam instability. Instead, the resonant EM RH ion beam instability dominates when the ion drift velocity is larger than the Alfvén speed, leading to the generation of RH Alfvén waves and RH whistler waves. We find that the intensity of Alfvén waves decreases with decrease of ion beam drift velocity, while the intensity of whistler waves increases. Our results provide new insights into the complex interplay between ion beams and plasma instabilities in low β collisionless space plasmas.