Hall推力器内饱和鞘层下电子与壁面碰撞频率特性

利用二维粒子模拟方法研究Hall推力器内电子与壁面的碰撞频率.研究发现,饱和鞘层状态下的电子与壁面的碰撞频率较经典鞘层下大大增加,甚至高出经典鞘层状态下电子与壁面碰撞频率两个数量级,这样饱和鞘层状态下电子与壁面的碰撞频率对近壁电流的贡献将不容忽略.进一步分析造成饱和鞘层状态下电子与壁面碰撞频率增加的原因后认为,饱和鞘层状态下电子与壁面碰撞频率的增加是鞘层电势降过低和壁面发射的二次电子回流造成的. 关键词： 饱和 鞘层 碰撞 频率

Features of electron-wall collision frequency with saturated sheath in Hall thruster

In the paper we study the electron-wall collision frequency in Hall thruster using the two-dimensional particle-in-cell method. It is found that electron-wall collision frequency is greatly increased in the state of saturated sheath compared with in the state of classic sheath, and even two orders of magnitude higher. Thus, the contribution of electron-wall collision frequency in the state of saturated sheath to near-wall current will be non-ignorable. In this paper the reason why the electron-wall collision frequency is increased in the state of saturated sheath is further analysed. It is believed that the increase of electron-wall collision frequency is caused by rather low sheath potential drop and the backflow of secondary electron emitted from the wall.