The onset and development of Kelvin-Helmholtz instability at the Venus ionopause
The onset and development of Kelvin-Helmholtz instability at the Venus ionopause
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DOI：
10.1029/ja085ia13p07697
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发表时间：
1980-12-30
影响因子：
2.8
通讯作者：
Yeates, C. M.
中科院分区：
文献类型：
--
作者：
Wolff, R. S.;Goldstein, B. E.;Yeates, C. M.
我们调查的Kelvin-Helmholtz不稳定性在金星电离层顶的流动（冲击）太阳风切向的电离层顶的情况下，行星际磁场是面向正常的流动方向。结果表明，重力稳定的长波长扰动，和边界层的有限厚度稳定的短波长模式。由于有限的拉莫尔半径效应的磁'回转粘度'要么不稳定的边界或稳定它根据太阳风电场点远离或朝向电离层。对于与先锋金星观测一致的太阳风和电离层等离子体参数，我们发现具有最大增长率（最短增长时间）的不稳定性具有类似于50-150 km的波长和类似于0.5到几秒的增长时间。此外，我们展示了如何扭曲的电离层顶的开尔文-亥姆霍兹不稳定性可能会导致形成的磁“通量绳”内的电离层以及电离层的“气泡”嵌入太阳风。
We investigate the Kelvin-Helmholtz instability at the Venus ionopause resulting from the flow of the (shocked) solar wind tangential to the ionopause for the case where the interplanetary field is oriented normal to the direction of flow. It is found that gravity stabilizes the long wavelength perturbations, and the finite thickness of the boundary layer stabilizes short wavelength modes. The magnetic 'gyroviscosity' due to finite Larmor radius effects either destabilizes the boundary or stabilizes it according to whether the solar wind electric field points away from or toward the ionosphere. For solar wind and ionosphere plasma parameters consistent with Pioneer Venus observations we find that the instabilities with the greatest growth rates (shortest growth times) have wavelengths of similar to 50-150 km and growth times of similar to 0.5 to several seconds. In addition, we show how distortion of the ionopause by Kelvin-Helmholtz instability might lead to the formation of magnetic 'flux ropes' inside the ionosphere as well as ionospheric 'bubbles' embedded in the solar wind.