The calculation of grain charge in a dense dusty plasma with a nonuniform surface potential

Abstract

Any study of astrophysical and laboratory dusty plasmas takes into consideration the calculation of individual dust grain charge when part of a dust cloud. At sufficiently high dust cloud densities, the effective Debye length of the cloud is of the same order as the intergrain distance, and the individual dust grains cannot be considered to be electrically isolated. As well, at moderate plasma temperatures, currents such as the secondary-electron current become significant and can be strongly radius-dependent at submicron levels. Thus, in these dusty plasma regimes the dust surface potential is not uniform throughout a cloud which has a distribution of grain sizes. We present the derivation of dust grain charge in a cloud with a size distribution immersed in a plasma, the dust cloud surface potential being nonuniform.