束—等离子体放电中低频等离子体波的非稳定性研究

本文采用非中性冷等离子体模型,研究了沿磁场入射的电子束和等离子体相互作用引起的低频等离子体波的非稳定性。计算表明,在束-等离子体放电情况下,振动频率和增长率都随电子束密度增加而增加,当束电流一定时,它们随l增加而略有增加。l=1时其频率数量级与离子迴旋频率相同。l≥3时,振动频率几乎不随k_z变化,其振动频率和增长率数量级与低混杂振荡频率相同,实质是低混杂漂移非稳定性。理论结果与实验一致。

STUDY OF LOW FREQUENCY PLASMA WAVE INSTABILITY IN BEAM PLASMA DISCHARGE

The low frequency plasma wave instability caused by interaction of plasma with electron beam injected along magnetic field is studied using a nonneutral cold plasma model.Numerical results show that in beam plasma discharges,the oscillation frequency and growth rate increace with electron beam density and with 1 for fixed beam currents.For l=1,the frequency has the same order of magnitude as the ion cyclotron frequency.For l=3,the osillation frequency does not change with kz the frequency and growth rate are equal to that of the lower hybrid oscillation by order of magnitude and its properties are consistent with the lower hybrid drift instability.Our results are in good agreement with experiments.