P70霍尔推力器新型缓冲腔磁路对预电离及放电的影响

Effects of a new buffer magnetic circuit on preionization and discharge in a P70 Hall thruster

为有效利用从P70霍尔推力器放电通道进入缓冲腔的快电子能量,考虑两个磁场特征以提高缓冲腔预电离率。一是提高磁感应强度,二是缓冲腔内从气体分配器到放电通道方向的负梯度。采用FEMM有限元磁场计算软件,在不改变推力器电离和加速通道内优化磁场特征的前提下,设计的新型缓冲腔磁路满足上述磁场特征。放电实验结果表明,在新型缓冲腔磁路下放电电流低频振荡幅值更小。新型磁路有助于延长推力器寿命,有助于电离和加速通道内电离与加速区的分离。

To recycle fast electron energy from discharge channel into buffer chamber in a P70 Hall thruster,the characteristics of magnetic field were considered to improve the preionization ratio in the buffer chamber.The first characteristic is the higher magnetic flux density.The second characteristic is the negative gradient from gas distributor to discharge channel.The new magnetic circuit is designed by FEMM magnetic field calculation software.The magnetic field of new magnetic circuit satisfied the above characteristics on the premise of not changing the optimized magnetic field in the ionization and acceleration channel.Experimental results indicate that the amplitude of discharge current low frequency oscillation is smaller.The new magnetic circuit is helpful for prolonging the thruster lifetime and improving separation of ionization zone as well as the acceleration zone in discharge channel.