Dusty Plasma Structures in Gas Mixtures

Abstract

The possibility of attainment of large Mach numbers is analyzed for the case of heavy ions drifting in a light gas [1]. Under conditions of typical experiments with dust structures in plasmas, the use of the mixture of light and heavy gases is shown to make it possible to suppress the ion heating in the electric field and to form supersonic flows characterized by large Mach numbers. The drift of krypton ions in helium is considered as an example. Experiments with dc glow discharge at 1–10% of Kr show that the transition to the discharge in mixture leads to increase of interaction anisotropy and reinforcement of coupling of dust particles in the direction of ion drift. On the other hand, under certain conditions the phenomenon of abnormal “heating” of dust particles was observed when the particles can obtain high kinetic energy which is several orders of magnitude higher than typical.