中文摘要：

为进一步探索霍尔推力器通道内等离子体鞘层的物理机制，针对霍尔推力器等离子体鞘层区域建立二维物理模型，采用二维粒子模拟方法研究了二次电子发射系数、鞘层电子数密度、鞘层电势以及电场随离子入射速度的变化规律，分析了模拟区域径向尺度大小对鞘层稳定性的影响。结果表明：壁面二次电子发射系数随离子入射速度的增大有少许增大，变化在10^-3数量级；随着离子入射速度的增大，电子数密度、鞘层电势降及径向电场都减小，而轴向电场几乎不变；在相同的边界条件下，模拟区域径向尺度的增大会导致壁面电势随时间的振荡加剧，鞘层稳定性降低。

英文摘要：

For further understanding the plasma sheath in Hall thruster, we built a 2D physical model for the sheath re gion in discharge channel and calculate the electric field at particle position using PIC simulation. The laws of changing secondary electron emission coefficient, electron number density, sheath potential and electric field in different ion inci dent velocities are discussed, and the stability of the sheath with different radial lengths is analyzed. The simulation indicates that as the ion incident velocity increases, the secondary electron emission coefficient increases slightly within 10.3 orders of magnitude, but both the sheath potential and radial electric field decrease, while changing ion incident ve locity hardly influences axial electric field. With the same boundary conditions, wall potential oscillation is intensified but the stability of the sheath decreases with increasing simulation region＇s axial scale.