Kinetic modelling of dusty plasmas

Abstract

AbstractModelling of ECR‐heated methane plasmas was done using a particle‐in‐cell code with collisions (PIC MCC) to get a better understanding in the problem of carbon layer production and chemical sputtering in such plasmas, which serve as a model system of divertor plasmas being dominated by carbon sputtering, especially at detached conditions. A fully kinetic model (PICMCC, resolving also the sheath in front of the wall) including all relevant species and their reactions (neutrals, ions, electrons) was developed and applied. The same model was used to study capacitive RF discharges which are also used to create so‐called plasma crystals. Depending on neutral gas pressure different plasma conditions appear (determined by the importance of collisions with neutrals). For low neutral densities rather dynamic plasma profiles and distribution function emerge (stochastic Fermi heating), whereas for high densities quasi‐stationary conditions show up. These are then used for the study of plasma crystals, where the dust particles are introduced as additional species in the model.The creation mechanism of these quasi‐ordered systems are discussed (force balance between gravitational force and electrostatic electric field force in the sheath) with special emphasis of the ion‐dust interaction (ion drag force) establishing also dust molecules through focussing of ion flows in the sheath regions of such discharges. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)