Generation of high-frequency broadband electrostatic noise: The role of cold electrons
Generation of high-frequency broadband electrostatic noise: The role of cold electrons
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高频宽带静电噪声的产生：冷电子的作用
DOI：
10.1029/ja092ia06p05807
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
M. Ashour‐Abdalla
中科院分区：
文献类型：
--
作者：
D. Schriver;M. Ashour‐Abdalla
宽带静电噪声(BEN)是与离子束有关的等离子体片边界层中常见的噪声。在这里，我们研究了由离子束和热离子、热电子和冷电子组成的等离子体中这些波的产生。冷电子来自电离层。对包括冷电子在内的静电离子束不稳定性进行了全面、系统的研究，结果表明，对于所描述的等离子体构型，可以激发四个不稳定性。它们是(1)离子声学，(2)邦曼，(3)束流共振，和(4)电子声不稳定性。结果表明，当激发不同的不稳定性时，存在高、低束流温度的分离。对于等离子体片边界层中的典型观测参数，离子束位于高温区。在这种情况下，束流共振和电子声学不稳定性被激发，这些不稳定性可以解释本光谱的高频(>；500赫兹)、低功率部分。在没有冷电子的情况下，不会发生这样的波增长。
Broadband electrostatic noise (BEN) is commonly observed in the plasma sheet boundary layer in association with ion beams. Here we investigate the generation of these waves in a plasma consisting of an ion beam and a background of hot ions, hot electrons, and cold electrons. The cold electrons are of ionospheric origin. A complete, systematic study of electrostatic ion beam instabilities, including cold electrons, has been done, and it is shown that for the plasma configuration described, four instabilities can be excited. These are the (1) ion acoustic, (2) Buneman, (3) beam resonant, and (4) electron acoustic instabilities. A low and high beam temperature division is shown to exist that separates when different instabilities can be excited. For typically observed parameters in the plasma sheet boundary layer, the ion beams lie in the high-temperature regime. In this regime, the beam resonant and electron acoustic instabilities are excited, and these instabilities can account for the high-frequency (> 500 Hz), low-power portion of the BEN spectrum. In the absence of cold electrons, no such wave growth occurs.