COLLECTIVE MODES IN NONRELATIVISTIC ELECTRON-POSITRON PLASMAS
COLLECTIVE MODES IN NONRELATIVISTIC ELECTRON-POSITRON PLASMAS
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DOI：
10.1103/physreve.47.604
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发表时间：
1993-01-01
影响因子：
2.4
通讯作者：
IWAMOTO, N
中科院分区：
文献类型：
--
作者：
IWAMOTO, N
研究了非相对论正负电子等离子体中的纵模和横模在有无静均匀磁场两种情况下的分布。无磁场时纵模和横模的色散关系以及有磁场时纵模的色散关系(伯恩斯坦模)与单组分电子等离子体的色散关系相似。另一方面，发现在磁场作用下的横模与电子-离子等离子体有很大的不同：平行于磁场传播的左、右圆极化波的色散关系是相同的。除了横向等离子体振荡外，还存在低频Alfven模，而不存在哨声模。对于垂直于磁场传播的波，非常波变成纯横模。在冷等离子体极限下，非常模的回旋频率和截止频率只有一个共振，而电子-离子等离子体则有两个混合共振和两个截止频率。
The longitudinal and transverse collective modes in a nonrelativistic electron-positron plasma are studied in two cases: a static uniform magnetic field is present or absent. The dispersion relations for the longitudinal and transverse collective modes in the absence of a magnetic field and those for the longitudinal mode in the presence of a magnetic field (Bernstein mode) are found to be similar to those for the one-component electron plasma. The transverse modes in the presence of a magnetic field, on the other hand, are found to be quite different from the electron-ion plasma: The dispersion relations for the left- and right-circularly polarized waves propagating parallel to the magnetic field are found to be identical. In addition to the transverse plasma oscillations, the low-frequency Alfven mode exists, while the whistler mode does not exist. For waves propagating perpendicular to the magnetic field, the extraordinary wave becomes a pure transverse mode. In the cold-plasma limit, there is only one resonance at the cyclotron frequency and one cutoff frequency for the extraordinary mode, in contrast to the electron-ion plasma, where there are two hybrid resonances and two cutoff frequencies.