等离子体鞘层附近尘埃颗粒特性的数值模拟

摘要

Collisionless steady plasma sheath model is taken into account to study the interaction between dusty particles and plasma sheath as well as the density distributions of electrons,ions and dusty particles.Numerical simulation results are obtained,showing that the ability of an isolated charge to absorb electrons weakens with the increase of dusty particle density and its temperature,while the collective effect strengthens with the radius of dusty particle.Simultaneously,Bohm velocity and the sheath thickness are also greatly affected.The sheath potential decreases significantly and the iJ-field is stronger near the electrode.In addition,the densities of electrons and ions reduce exponentially but the dusty particle has a critical value.The three particles satisfy the quasi-neutrality condition.%为了研究尘埃等离子体中尘埃颗粒以及鞘层中粒子密度分布等特性,对尘埃颗粒存在条件下等离子体鞘层结构的采取数值模拟.采用稳态无碰撞的尘埃等离子体鞘层模型,对玻姆判据、尘埃颗粒的荷电性质、平板鞘层区域的电势分布及鞘层内粒子分布特性进行了系统的数值模拟研究.计算结果显示,鞘层边缘尘埃颗粒数密度的增加、尘埃温度的升高,将引起孤立尘埃颗粒对电子吸附能力的减弱,集体效应也受到一定程度的影响;二者同时对离子玻姆速度以及鞘层厚度的增加都有着极大的促进作用.鞘层电势在靠近下极区处降落迅速,主要聚集在接近阴极极板的鞘层区域,各种微粒数密度的空间分布满足准中性条件.