Instabilities in inhomogeneous complex plasma

Abstract

Summary form only given, as follows. Problems associated with the formation and growth of instabilities in dissipative systems of interacting particles are under discussion in the varied fields of science (plasma physics, molecular biophysics, hydrodynamics etc.). A good experimental model for a study of instabilities in such is a dusty plasma. Dusty plasma consists of electrons, ions, neutral gas molecules and micron size charged dust particles. Usually the dust particles achieve electrostatic equilibrium with respect to the plasma by acquiring negative charge. This charge is not fixed but is coupled self-consistently to the surrounding plasma parameters. For this reason, new instabilities can develop in dusty plasma, leading to different self-exited dynamic phenomena observed in dust structures. A novel type of instability in inhomogeneous dusty plasma is considered. It is shown that spatial particle charge variation, which can occur due to an inhomogeneity of the bulk plasma surrounding the dust cloud, for example, due to the gradients of concentration n/sub e(i)/ or temperature T/sub e(i)/ of electrons (ions), provides an effective mechanism to excite motion of the dust. The results of numerical simulation of a dust plasma system with a spatial charge gradient and experimental observation of instabilities in a RF-discharge plasma are presented. Numerical simulations of the grain systems in the external electric and gravity fields were carried out using molecular dynamics method. Conditions suitable for observing various self-excited motions (vortices, oscillations and convection motion) of dust particles in the RF-glow discharge are discussed.