磁场对霍尔推力器放电特性及性能参数影响的粒子模拟研究

磁场强度及位形对霍尔推力器放电过程有显著影响。根据霍尔推力器通道尺寸和等离子体放电过程建立二维物理模型,采用粒子模拟方法,研究了不同磁场强度及位形等离子体放电特性,讨论了推力、推功比及放电电流的变化规律。模拟表明:当中轴线磁场强度峰值小于200G时,磁场对电子轴向传导约束减弱;当磁场强度峰值在200G～420G时,电子温度、电离率及电子与壁面碰撞频率降低,出口处离子径向速度增大,壁面腐蚀增加;当磁场强度峰值为280G时,加速区最短,放电电流最小。不同零磁点磁场位形会改变通道电离区和加速区位置,影响推力器放电性能。

Particle-in-Cell Simulation on Effects of Magnetic Field onDischarge Characteristics and Performance of Hall Thruster

The magnetic field intensity and configuration have significant influence on the discharge process of Hall thruster. In this work, a two-dimensional physical model based on the channel size of Hall thruster and the physical process of plasma discharge is established. The PIC simulation method is applied to study the discharge characteristics of plasma with different magnetic field distributions, and discuss the variation of thrust, thrust to power ratio and discharge current. The simulation results show that the peak magnetic field intensity of the central axis is less than 200 Gauss, the restraint of the magnetic field on the electron conduction on the axial direction decreases. When the peak magnetic field intensity is between 200-420 Gauss, the electron temperature, ionization rate and the collision frequency between electrons and the wall decrease, the radial velocity of ions at the outlet increases, and the wall corrosion increases. When the peak magnetic field intensity is 280 Gauss, the length of acceleration region become minimal and the value of discharge current drop to a minimum. Magnetic field configurations with different zero magnetic point will change the position of ionization and acceleration zones in the channel and affect the discharge performance of the thruster.