Current-driven instabilities in a laminar perpendicular shock
Current-driven instabilities in a laminar perpendicular shock
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层流垂直激波中电流驱动的不稳定性
DOI：
10.1029/ja083ia04p01625
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发表时间：
1978
影响因子：
--
通讯作者：
S. Gary
中科院分区：
文献类型：
--
作者：
D. Lemons;S. Gary
研究了磁场电流驱动的全电磁等离子体不稳定性的线性理论，并应用于层流垂直弓形激波。该理论采用局域近似，假设未磁化的离子和磁化的电子，并考虑了磁场大小和密度梯度的影响。考虑斜向传播，波数可能等于或大于电子的倒数拉莫尔半径。电子β的增加不会显著影响离子的声学不稳定性，但会降低布尼曼不稳定性和修正的双流不稳定性的增长率。如果Te»Ti在激波中，结果表明离子的声学不稳定性是最重要的生长模式，对于任何合理的β。如果在整个冲击过程中Te < ti，则需要进一步的工作来确定哪种不稳定性是最重要的。
The linear theory of fully electromagnetic plasma instabilities driven by currents flowing across a magnetic field is investigated, with applications to the laminar perpendicular bow shock. The theory utilizes the local approximation, assumes unmagnetized ions and magnetized electrons, and includes the effects of gradients in the magnetic field magnitude and density. Oblique propagation is considered, and wave numbers may be of the order of or larger than the reciprocal electron Larmor radius. An increase in the electron beta does not significantly affect the ion acoustic instability but does reduce the growth rates of the Buneman and the modified two-stream instabilities. If Te » Ti within the shock, results indicate that the ion acoustic instability is the most important growing mode, for any reasonable beta. If Te < Tι throughout the shock, further work is necessary to determine which instability is most important.