Observation of electron bunching during Landau growth and damping
Observation of electron bunching during Landau growth and damping
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DOI：
10.1029/91ja00658
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发表时间：
1991-07
影响因子：
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通讯作者：
R. Ergun;C. Carlson;J. Mcfadden;D. M. TonThat;J. Clemmons;M. Boehm
中科院分区：
文献类型：
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作者：
R. Ergun;C. Carlson;J. Mcfadden;D. M. TonThat;J. Clemmons;M. Boehm
最近，一枚极光探测火箭首次发射了一种高频波粒相关仪。对电子聚集的直接观察表明，大振幅朗缪尔波与低能、场向电子共振，大致符合预期。然而，观察到的电子聚束似乎与电场信号（或180°反相）而不是波势，表明正在发生能量交换。基本能量传递分析表明，朗道生长或阻尼可以解释电子聚集。蒙特卡罗测试粒子模拟支持该模型。模拟结果表明，在粒子与波相互作用后，在大约一半的弹跳周期内，电子分布函数与电场相扰动，随后粒子在波势中被捕获。后一种效应没有被观察到，对此我们提供两种解释。要么是由于有限的频率带宽和变化的波长而没有发生粒子捕获，要么是波包的物理尺寸太小而无法建立粒子捕获。
A high-frequency wave-particle correlator instrument has been flown for the first time on a recent auroral sounding rocket. The direct observation of electron bunching showed that large-amplitude Langmuir waves were resonant with low-energy, field-aligned electrons, roughly corresponding to expectations. The observed electron bunching, however, appeared to be in phase (or 180° out of phase) with the electric field signal rather than the wave potential, indicating that an energy exchange was occurring. An elementary energy transfer analysis shows that Landau growth or damping could account for the electron bunching. A Monte Carlo test particle simulation supports this model. The simulation shows a perturbation of the electron distribution function in phase with the electric field for roughly half of a bounce period after the particles interact with the wave, followed by particle trapping in the wave potential. The latter effect was not observed, for which we offer two interpretations. Either the particle trapping did not occur due to finite frequency bandwidths and changing wavelengths, or the physical size of the wave packet was too small to establish particle trapping.