微放电等离子体多负辉区结构融合过程数值模拟研究

摘要

高气压下的微型电热推进器(MPT)中的放电等离子体存在多负辉区结构,其负辉区有融合趋势.对矩形微放电等离子体推进器(RMPT)的负辉区融合过程进行了二维模拟分析,在方法上采用了非平衡态的自洽流体模型,并考虑了离子电流加热和三体碰撞过程.结果显示:矩形微放电等离子体推进器(RMPT)在低电流条件下存在两个稳定的负辉区,当超过某一电流阈值条件后,两个负辉区会在腔体中心重合.分析了这一过程的成因,认为其融合过程本质上是空心阴极的导通过程,其融合与否与鞘层电压有关.%The discharge plasma in the rectangular micro hollow cathode (RMHCD) under high pressure has a multiple negative glow region structure, and the negative glow regions have a tendency of fusion, which can significantly increase the ionization efficiency.The gas is confined in the cavity, which can be effectively heated, and thus can be applied to micro-electric plasma thruster (MPT).In this paper, the 2D x-y cross-section of a rectangular micro-discharge plasma thruster (RMPT) is simulated and analyzed, and a self-consistent fluid model with non-equilibrium state is adopted in the method.The ion current heating and the three-body collision are also considered.The results show that the RMPT has two stable negative glow regions under low current conditions.When a certain current threshold is exceeded, the two negative glow regions will merge at the center of the cavity.Corresponding analysis suggests that the fusion process is essentially a hollow cathode conduction process, whether or not the fusion of negative glow regions occurs is related to sheath voltage.