Pattern Formation in a Dusty Plasma System

A rich variety of dust patterns have been observed in a capacitively coupled rf discharge dusty plasma system. Dust particles are synthesized through chemical reaction of the filled gas mixture during discharge. Different patterns are formed in different stages of particle growth. In the early stage of particle growth, dust cloud can be formed by a large number of small particles, and its behavior appears to be fluid-like. Such interesting nonlinear phenomena as dust void and complex dust cloud patterns are observed in this stage. As dust particles grow, the particle size and structure can be controlled to follow two different routes. In one of the routes, the particles grow up in a ball-like shape and can be formed into regular lattice and cluster patterns. In the other, the particles grow up in a fractal shape.     

The Drift of Dust Grains Induced by Transient Magnetic Field

Our experiment shows that the dust grains ,suspended on the edge of the sheath of a radio-frequency discharge,undergo a contraction when switching a vertical magnetic field on ,and an expansion when switching the magnetic field off .We call this kind of magnetic field“transient magnetic field”.A primary analysis is proposed for the phenomenon.