Microphysics of Cosmic Plasmas: Hierarchies of Plasma Instabilities from MHD to Kinetic
Microphysics of Cosmic Plasmas: Hierarchies of Plasma Instabilities from MHD to Kinetic
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DOI：
10.1007/s11214-013-0005-7
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发表时间：
2013-08
影响因子：
10.3
通讯作者：
M. Brown;P. Browning;M. Dieckmann;I. Furno;T. Intrator
中科院分区：
文献类型：
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作者：
M. Brown;P. Browning;M. Dieckmann;I. Furno;T. Intrator
在这篇文章中，我们讨论了一个层次的不稳定性，可以迅速耦合不同尺度的湍流等离子体系统的想法。首先，在系统的最大尺度L处，载流通量绳可能经历扭结不稳定性。其次，相邻磁通绳中的扭结不稳定性可以迅速地将磁通束聚集在一起并驱动重联，引入电流片宽度的新尺度，也许是几个离子惯性长度（δi）。最后，由重连电场驱动的强电流片可以使动力学波（诸如离子回旋波）不稳定，只要电子的漂移速度与离子热速度相比大。像这样的不稳定性可以将磁流体动力学尺度与动力学尺度耦合起来，小到质子拉莫尔半径ρi。
In this article, we discuss the idea of a hierarchy of instabilities that can rapidly couple the disparate scales of a turbulent plasma system. First, at the largest scale of the system,L, current carrying flux ropes can undergo a kink instability. Second, a kink instability in adjacent flux ropes can rapidly bring together bundles of magnetic flux and drive reconnection, introducing a new scale of the current sheet width,ℓ, perhaps several ion inertial lengths (δi) across. Finally, intense current sheets driven by reconnection electric fields can destabilize kinetic waves such as ion cyclotron waves as long as the drift speed of the electrons is large compared to the ion thermal speed,vD≫vi. Instabilities such as these can couple MHD scales to kinetic scales, as small as the proton Larmor radius,ρi.