Electron beam formation by small‐scale oblique inertial Alfvén waves

Electron beam formation by small‐scale oblique inertial Alfvén waves
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小尺度倾斜惯性阿尔文波形成电子束

DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
C. Seyler
C. Seyler
中科院分区：
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文献类型：
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作者：
A. Clark;C. Seyler

文献摘要

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粒子模拟揭示了在静电极限、波陡化和电子束产生过程中，小尺度、近垂直的非线性惯性Alfven波的特征。这些静电惯性Alfven波(ESIAW)只在Ti/Te&gt；&gt；1的弱电子朗道衰减下传播。非线性振幅初始条件对流变陡，并演化出在形态和量级上类似于以前流体动力学模型结果的较高波数结构。在陡化的ESIAW波演化过程中出现的较短波长的声波被发现有助于激发动能为热电子数几百倍的冷电子束。这一机制是在极光倒置V事件及其附近观察到的超热电子爆发的一种可能解释。
Particle-in-cell simulations reveal characteristics of small-scale nearly perpendicular nonlinear inertial Alfven waves in the electrostatic limit, during wave steepening and electron beam generation. These electrostatic inertial Alfven waves (ESIAW) propagate with only weak electron Landau damping for T i /T e >>1. Nonlinear amplitude initial conditions convectively steepen and evolve higher wavenumber structures similar in morphology and magnitude to previous results from a fluid-kinetic model. Shorter wavelength acoustic waves emergent during steepened ESIAW wave evolution are found to be instrumental in exciting cold electron beams possessing kinetic energies a few hundred times that of the thermal electron population. This mechanism is one possible explanation for suprathermal electron bursts observed in and near auroral inverted-V events.