Ion Beam Instability in Hall Thrusters
Ion Beam Instability in Hall Thrusters
复制标题
霍尔推进器中的离子束不稳定性
DOI：
10.1109/tps.2014.2343452
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发表时间：
2015
影响因子：
1.5
通讯作者：
E. Behar
中科院分区：
文献类型：
--
作者：
A. Kapulkin;E. Behar
用理论和数值模拟的方法研究了霍尔推进器中阳极和阴极约束离子通量的稳定性。采用冷磁化电子和冷非磁化离子的双流体磁流体近似。考虑了电子的惯性。假设摄动是准中性的，位势的，并且只依赖于单一的空间坐标。为简单起见，假设磁场是均匀的。结果表明，离子束势固定的边界的存在会引起束流的不稳定性。不稳定和频率激发振荡的增长速率是阳极和阴极之间的离子交叉时间的倒数量级。在等离子体均匀无扰状态的极限下，这种不稳定性类似于电子束的皮尔斯不稳定性，其根本区别在于，在这里，微扰是准中性的。结果表明，这种不稳定性是周期性的和振荡的，取决于αLH参数的范围，包括磁场感应(通过较低的混合频率)、加速层的厚度和离子通量的速度。
Stability of an ion flux, bounded with an anode and cathode, in Hall thrusters is investigated by theoretical and numerical modeling. Two-fluid magnetohydrodynamic approximation with cold magnetized electrons and cold nonmagnetized ions is used. The inertia of the electrons is taken into consideration. The perturbations are assumed to be quasi-neutral, potential, and dependent on a single spatial coordinate only. For simplicity, the magnetic field is assumed to be uniform. It is shown that the presence of the boundaries, where the potential of the ion beam is fixed, can cause instability of the beam. The growth rate of instability and frequency excited oscillation is of the order of the reciprocal of the ion crossing time between the anode and cathode. In the limit of a uniform unperturbed state of plasma, the instability is analogous to the Pierce instability of an electron beam with the fundamental distinction that here, the perturbations are quasi-neutral. It is shown that the instability is alternately a periodical and oscillating depending on the range of the αlh parameter, which includes induction of the magnetic field (through lower hybrid frequency), thickness of the acceleration layer, and velocity of the ion flux.