Instability in a Perpendicular Collisionless Shock Wave for Arbitrary Ion Temperatures
Instability in a Perpendicular Collisionless Shock Wave for Arbitrary Ion Temperatures
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任意离子温度下垂直无碰撞冲击波的不稳定性
DOI：
10.1063/1.1693632
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发表时间：
1971
影响因子：
4.6
通讯作者：
C. Lashmore
中科院分区：
文献类型：
--
作者：
C. Lashmore
考虑了在垂直无碰撞冲击波的条件下可能发生的两种不稳定机制。这两种机制都是由于电子伯恩斯坦波在激波中沿电流方向传播的负能量特性造成的。考虑了激波中电压跃变的影响，以及激波前沿的密度和磁场梯度。两种不稳定机制仅发生在 k 值的确定范围内。第一种机制是由于离子声波和伯恩斯坦谐波之一之间的共振，第二种机制是共振离子从负能量伯恩斯坦模式吸收能量。第一种情况需要 Te≫Ti，而第二种情况可能发生在 Ti/Te 比率的任意值的情况下，尽管当该比率为单位阶时会出现最大效果。
Two instability mechanisms which could occur under the conditions found in a perpendicular collisionless shock wave are considered. Both mechanisms are due to the negative energy character of the electron Bernstein waves propagating in the direction of the current flow in the shock. The effect of the voltage jump through the shock, and the density and magnetic field gradients at the shock front are considered. Both instability mechanisms occur only within a definite band of k values. The first mechanism is due to a resonance between the ion acoustic wave and one of the Bernstein harmonics and the second to resonant ions absorbing energy from a negative energy Bernstein mode. The first case requires Te≫Ti whereas the second case can occur for arbitrary values of the ratio Ti/Te, although the maximum effect occurs when this ratio is of order unity.