Trapped ion effect on shielding, current flow, and charging of a small object in a plasma
Trapped ion effect on shielding, current flow, and charging of a small object in a plasma
复制标题
DOI：
10.1063/1.1562163
复制
发表时间：
2003-05-01
影响因子：
2.2
通讯作者：
Joyce, G
中科院分区：
文献类型：
--
作者：
Lampe, M;Goswami, R;Joyce, G
沉浸在不流动等离子体中的小型球形收集器周围的静电屏蔽问题，以及电子和离子流向收集器的相关问题，可以追溯到等离子体物理学的起源。计算通常忽略了碰撞，理由是平均自由程比德拜长度长。然而，长期以来人们一直怀疑偶然碰撞产生的负能量捕获离子可能很重要。本文给出了捕获和未捕获离子的密度和分布函数、电位分布、流向集电极的离子和电子电流以及集电极的浮电位和电荷的自一致解析计算。在典型条件下，尘埃颗粒浸泡在放电等离子体中，即使平均自由程远远大于德拜长度，捕获离子也会主导颗粒附近的屏蔽，大大增加颗粒的离子电流，抑制悬浮电位和颗粒电荷。(C) 2003年美国物理研究所。
The problem of electrostatic shielding around a small spherical collector immersed in nonflowing plasma, and the related problem of electron and ion flow to the collector, date to the origins of plasma physics. Calculations have typically neglected collisions, on the grounds that the mean free path is long compared to the Debye length. However, it has long been suspected that negative-energy trapped ions, created by occasional collisions, could be important. This paper presents self-consistent analytic calculations of the density and distribution function of trapped and untrapped ions, the potential profile, the ion and electron current to the collector, and the floating potential and charge of the collector. Under typical conditions for dust grains immersed in a discharge plasma, trapped ions are found to dominate the shielding near the grain, substantially increase the ion current to the grain, and suppress the floating potential and grain charge, even when the mean free path is much greater than the Debye length. (C) 2003 American Institute of Physics.