热电子对低频等离子体漂移波的稳定作用

STABILIZING EFFECTS OF HOT ELECTRONS ON LOW FREQUENCY PLASMA DRIFT WAVES

本文用磁流体理论导出了热电子等离子体中,等离子体密度梯度驱动的低频漂移波的色散关系,分析了热电子的稳定作用。热电子成分稳定等离子体低频扰动的物理机制是chargeuncovering效应,它只依赖于热电子同等离子体的密度比α,而不依赖于热电子的β值。热电子能降低等离子体交换模和漂移波的增长率,减少漂移波引起的等离子体反常输运损失。稳定等离子体交换模要求α2％,稳定等离子体漂移波要求α40％。理论上预示了在热电子等离子体中,等离子体漂移波是最重要的低频不稳定性。

The MHD equation is used to study the stabilization of low frequency drift waves driven by density gradient of plasma in a hot electron plasma. The dispersion relation is derived, and the stabilizing effects of hot electrons are discussed. The physical mechanism for hot electron stabilization of the low frequency plasma perturbations is charge uncovering due to the hot electron component, which depends only on a, the ratio of Nb/Nt, but not on the value of βh. The hot electrons can reduce the growth rate of the interchange mode and drift wave driven by the plasma, and suppress the anomalous plasma transport caused by the drift wave. Without including the effect of βh, the stabilization of the interchange mode requires α≈2%, and the stabilization of the drift wave requires α≈40%. The theoretical analyses predict that the drift wave is the most dangerois low frequency instability in the hot electron plasma.