论文标题
在等离子体速度空间不稳定性的碰撞阻尼
On the collisional damping of plasma velocity space instabilities
论文作者
论文摘要
对于由粒子分布驱动的等离子体速度空间不稳定性，与麦克斯威尔显着偏离，较弱的碰撞可以削弱不稳定性的数量，其量显着超出了碰撞率本身。这归因于碰撞的双重作用，这些碰撞倾向于放松对麦克斯韦的血浆分布并抑制线性扰动的分布函数。在不稳定的非马克斯威尔分布的驱动的情况下，在时间尺度上，不稳定的非马克斯威尔分布驱动的情况比碰撞的效果驱动，而理想不稳定性的增长率对分布函数具有敏感的依赖性。由静电捕获电子驱动的惠斯勒不稳定性被用作阐明等离子体速度空间不稳定性的这种强碰撞阻尼效应的示例，这是通过第一原理动力学模拟证实的。
For plasma velocity space instabilities driven by particle distributions significantly deviated from a Maxwellian, weak collisions can damp the instabilities by an amount that is significantly beyond the collisional rate itself. This is attributed to the dual role of collisions that tend to relax the plasma distribution toward a Maxwellian and to suppress the linearly perturbed distribution function. The former effect can dominate in cases where the unstable non-Maxwellian distribution is driven by collisionless transport on a time scale much shorter than that of collisions, and the growth rate of the ideal instability has a sensitive dependence on the distribution function. The whistler instability driven by electrostatically trapped electrons is used as an example to elucidate such a strong collisional damping effect of plasma velocity space instabilities, which is confirmed by first-principles kinetic simulations.
