On the formation of structural states in dusty plasmas

Abstract

The paper considers the basis of the approach used to study the response of dusty plasma clusters of various compositions in confining fields of various configurations. The problem statement and analysis are based on the concepts of physical mesomechanics. For an external confining field an electric field and gravity force combination is used. Calculations were performed in the framework of molecular dynamics. The interparticle interaction is described by the Debye-Hiickel pair isotropic potential. The charge of dust particles is calculated using the orbital motion limited theory. The parameters of the field configuration are determined with the use of experimental data. Calculations of both the structure of a formed dusty plasma cluster and the characteristic spacings of dust particles agree well with available experimental data. The emphasis in the paper is on the dependence of the structure and shape of dusty plasma clusters on the number of dust particles in confining fields of varying anisotropy. It is shown that in the crystalline state, dust particles form a Coulomb ball with a shell structure in an isotropic external field. It is pointed out that dusty plasma clusters can transform from the bulk to plane state. In the crystalline state, both plane and bulk dusty plasma clusters have a shell structure; however in the anisotropic state, their structure becomes more complex and split.