二次电子发射对无碰撞等离子体鞘层的影响

Effects of Secondary Electron Emission on Non-collisional Sheath

建立了包括器壁发射二次电子的等离子体无碰撞鞘层的基本模型,讨论了一维稳态等离子体鞘层中二次电子发射对鞘层结构的影响.结果表明:器壁电势随着二次电子发射系数的增加而增加.在发射系数小于临界发射系数时,鞘层电势随发射系数增加而增加,鞘层是离子鞘;在发射系数大于临界系数时,电场出现反转,电势在鞘层空间出现一最小值,鞘层不再是离子鞘.并且就稳态等离子体推进器器壁材料不同,简要分析了二次电子发射给其鞘层带来的影响.

In this paper, the basic model of non-collisional plasma sheath .is developed. The plasma consists of electrons, positively charged ions and secondary electrons from the wall. It is discussed that secondary electron emission （SEE） affects the sheath structure in steady state of one dimension. There are conclusions that the potential in the wall increases with the SEE coefficient. If γ〈γc, the potential in the sheath increases with the SEE coefficient, the sheath is sheath of ions. If γ〈γc,the electric field is reverse, there is a minimum in the sheath and the sheath is not sheath of ions. And as for the wall consisting of different materials for stationary plasma thruster, it is discussed briefly that SEE affects the sheath.