Charging of dust grains in a nonequilibrium plasma of a stratified glow discharge
- PDF / 491,598 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 28 Downloads / 217 Views
Y PLASMA
Charging of Dust Grains in a Nonequilibrium Plasma of a Stratified Glow Discharge G. I. Sukhinina, b and A. V. Fedoseeva a Kutateladze
Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 1, Novosibirsk, 630090 Russia b Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia Received February 19, 2007; in final form, March 30, 2007
Abstract—A theoretical model is presented that describes the charging of dust grains in the positive plasma column of a stratified glow dc discharge in argon. A one-dimensional self-consistent model is used to obtain axial profiles of the electric field, as well as the electron energy distribution function along the axis of the discharge tube. Radial profiles of the electric field are determined in the ambipolar diffusion approximation. It is assumed that, in the radial direction, the electron distribution function depends only on the total electron energy. Two-dimensional distributions of the discharge plasma parameters are calculated and used to determine the potential and charge of a test dust grain at a certain point within the discharge and the electrostatic forces acting on it. It is shown that the grain charge distribution depends strongly on the nonequilibrium electron distribution function and on the nonuniform distribution of the electric field in a stratified glow discharge. A discussion is presented on the suspension of dust grains, the separation of grains by size in the discharge striations, and a possible mechanism for the onset of vortex dust motion at the edge of a dust cloud. PACS numbers: 52.27.Lw, 52.20-j, 52.35.We DOI: 10.1134/S1063780X07120070
1. INTRODUCTION A dusty, or complex, plasma is an ionized gas composed of electrons, ions, and particles of condensed matter. Such a plasma is widely encountered in space (in planetary rings, interstellar clouds, comet tails, etc.) and also occurs in industrial devices and fusion reactors [1]. In recent years, dusty plasma has attracted the attention of investigators as a nonlinear dissipative system in which ordered dust structures can form. A laboratory dusty plasma is a good experimental model for investigating various problems of statistical physics, kinetic processes in nonideal plasma systems of strongly interacting particles, and phase transitions and wave processes in complex plasma systems. Laboratory dusty plasmas have been increasingly studied in experiments with stratified glow dc discharges [2–6], RF discharges [7–9], and discharges under microgravity conditions [10]. In experiments, a dusty plasma was observed as well-pronounced dust formations (clouds) in the electrode sheaths of capacitive and inductive RF discharges and in the striations of glow dc discharges. Dusty plasma in the positive column (PC) of a stratified glow discharge has been the object of extensive research since 1996 [2–6]. In discharges with certain parameters, different plasma structures may coexist, such as plasma crystals and dust–plasma liquids (regions of convectiv
Data Loading...
