霍尔推力器类低频电离振荡的新模型建立与特性研究

The Hall thruster is a plasma jet source, which ionizes propellant gas and accelerates ions under the effects of electric and magnetic fields. The low frequency oscillation, resulting from the unstablity of ionization, is a basic issue concerning the microscopic mechanisms and macroscopic properties of Hall thruster..As the existing numerical model analysis does not correspond with the experimental results of low frequency oscillation, this project intends to establish a practicable numerical analysis platform: a novel numerical model of low frequency oscillation in Hall thruster, basing on the differences of physical properties between the near-anode zone and the ionization-acceleration zone. This model would physically propose an effective sub-region description of electron motion in the near-anode zone and the ionization-acceleration zone, and mathematically determine the join conditions of expressions describing electron dynamic and stationary states, and methodologically solve the multi-time scale problem in the simulation of low frequency oscillation effectively..Research applying the new model and combined with expirements, would help revealing the mechamism of Hall thruster parameters in effecting the low frequency oscillation and plasma charecteristics in different oscillation modes, and furthermore contributes to the control of jet plasma parameters and optimazation of thruster's performance.

霍尔推力器是利用电磁场作用来实现工质电离与离子加速的等离子体射流源，电离不稳定状态所表现出的低频振荡特性是其内部微观机制与宏观性能研究的基础性课题。.针对现有数值模型无法准确反映低频振荡的实验测量结果，并基于推力器通道内近阳极区与电离-加速区物理特性的区别，本项目拟建立一种可行的数值分析工具/平台- - 霍尔推力器低频振荡新数值模型；物理上，给出近阳极区与电离-加速区电子动态特性的分区域有效性描述；数学上，确定出电子动态与稳态表达形式的结合/衔接条件；方法上，有效地解决低频振荡模拟中多时间尺度的计算难点。.应用所建立的新数值模型，结合实验研究，给出霍尔推力器工作参数对低频电离振荡影响机制和各类振荡形态下等离子体特性，为霍尔推力器射流等离子体参数的控制与性能优化提供方法支撑。

霍尔推力器的低频振荡过程包含了中性气体电离、磁场束缚电子，电场加速离子的综合过程，其振荡机制及特性的数值及实验研究是提高推力器效率的重点，也为等离子体理论及应用的发展奠定基础。. 本课题引入电子动态特性，建立霍尔推力器低频振荡新模型，仿真结果显示了电子与离子的动态联系；基于低频振荡过程分析，给出能反应振荡物理过程的机制模型；结合实验测量对低频振荡模型中温度方程的求解进行修正，修正后的模型所得电子温度与实验结果符合较好；在对低频振荡分类的基础上，给出磁场强度、放电电压及质量流量对低频振荡的综合影响，首次完成了推力器参数对低频振荡的整体描述；深入的分析表明低频振荡的模态受阴极发射能力的影响，通过阴极质量流量的调节，给出了阴极发射特性对低频振荡的影响，验证了理论分析结果；结合各工作参数对低频振荡的综合影响，给出推力器最佳工况选取方案，指导实际推力器工况选择。

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