Momentneutrality and dipole-screened model in the dusty plasma

Abstract

If a particle in an anisotropic plasma is replaced by a charge q0 and a dipole p0, without modifying the moment of the monopole and the dipole, the approximation method neglecting higher-order terms is not sufficient for describing the actual potential distribution around the particle. By introducing the concepts of the ‘apparent’ charge q and the ‘apparent’ dipole p in this paper, the surface potential of the particle caused by q0 + p0 and the sheath charge+dipole can be decided by q + p. If we assume that the dusty plasma has roughly equal moments of particle dipoles (+) and sheath dipoles (−), i.e. ‘momentneutrality’, besides the electroneutrality relation, the relationship between the actual moment and the ‘apparent’ moment can be acquired, and the potential around the particle can be calculated self-consistently. Based on the physical model, the electrostatic force on an isolated particle in an anisotropic plasma may be calculated and the pair interaction potential energy between particles or the coupling parameter can be acquired even for high κa values. Compared with other methods, the system is solvable analytically and thus yields clear insight into its physical behaviour.