磁聚焦霍尔推力器放电模式转变机理研究

In 2016, China has achieved on-orbit flight verification of magnetic focusing Hall thruster in the world for the first time. The performances meet the design requirements. The performances have been improved than other type Hall thruster, including the plume divergence angle has decreased, the specific impulse has increased. However，Experiments have found that there is an abnormal discharge mode in the magnetic focusing Hall thruster that is different from other type thruster. This discharge mode will cause the performances to decrease, the plume divergence angle to increase, and the current oscillation to strengthen, affecting the use of the thruster in orbit. Therefore, this study intends to simulate the physical process of discharge mode transition in magnetic focusing Hall thruster through two-dimensional PIC/MCC numerical simulation to study the process and mechanism of this abnormal discharge mode transition process. Using the knowledge of its basic physical processes, the performance of the thruster will be improved through the optimization of discharge parameters. And using the external network feedback loop control discharge parameters including discharge voltage, current in magnetic coil to achieve the purpose of increasing the discharge steady and extension parameter region of normal mode. These methods will improve the reliability of magnetic focusing Hall thruster in orbit applications.

2016年我国实现了磁聚焦霍尔推力器国际首次在轨飞行验证，性能满足设计要求，同比国内外其他型号的SPT型霍尔推力器性能提高，羽流发散角度减小，比冲同比提高。然而实验发现磁聚焦霍尔推力器存在一种有别于其他推力器的异常放电模式，这种放电模式会造成推力器性能下降，羽流发散角度增大，电流振荡增强，影响推力器在轨使用。因此本研究拟通过二维PIC/MCC数值模拟对磁聚焦霍尔推力器放电模式转变的物理过程进行仿真，研究异常放电模式转变的过程和机理。利用对其基本物理过程的认识，在实验上通过放电参数的优化实现推力器放电稳定性的提高。以及利用外回路反馈网络控制放电参数包括放电电压，励磁电流实现推力器稳定放电参数区域增大的目的，提高磁聚焦霍尔推力器在轨应用的可靠性。

2016年我国实现了磁聚焦霍尔推力器国际首次在轨飞行验证，性能满足设计要求，同比国内外其他型号的SPT型霍尔推力器性能提高，羽流发散角度减小，比冲同比提高。然而实验发现磁聚焦霍尔推力器存在一种有别于其他推力器的异常放电模式，这种放电模式会造成推力器性能下降，羽流发散角度增大，电流振荡增强，影响推力器在轨使用。本研究通过分析和试验给出了推力器的磁场和电场在周向不对称造成两种电子传导路径分别是磁场的不对称性引起的Ez×Bθ传导和电场的不对称引起的Eθ×Br传导路径。通过PIC-MCC和一维流体模型仿真了推力器的放电过程，对放电模式的转变机理进行了分析，给出了推力器放电模式转变的物理机制。最后在实验上利用外回路反馈网络控制放电参数包括放电电压，励磁电流实现推力器稳定控制。