Structures and Dynamics of a Two-Dimensional Confined Dusty Plasma System

The influence of the confining potential strengthand temperature on the structures and dynamics of a two-dimensional(2D) dusty plasma system is investigated through molecular dynamic(MD) simulation. The circular symmetric confining potential leadsto the nonuniform packing of particles, that is, an inner corewith a hexagon lattice surrounded by a few outer circular shells.Under the appropriate confining potential and temperature, theparticle trajectories on middle shells form a series of concentricand nested hexagons due to tangential movements of particles.Mean square displacement, self-diffusion constant, pair correlationfunction, and the nearest bond are used to characterize thestructural and dynamical properties of the system. With the increaseof the confining potential, the radial and tangential movementsof particles have different behaviors. With the increase of temperature,the radial and tangential motions strengthen, particle trajectoriesgradually become disordered, and the system gradually changesfrom a crystal or liquid state to a gas state.