Interaction potential among dust grains in a plasma with ion flow - art. no. 046406

Linear-response dielectric theory is used to study the interaction potentia l between dust grains in a flowing plasma, taking into account the finite s izes and the asymmetric charge distributions of the grains. This potential can be divided into two parts: a screened Coulomb potential and a wake pote ntial. The former is a short-ranged repulsive potential, while the later is a long-ranged oscillatory potential which acts only on trailing grains. Bo th the amplitude and wavelength of the wake potential depend on the Mach nu mber. The grain size and the asymmetric charge distribution may affect the interaction potential in a significant way when the distances between grain s are comparable with the grain size, or when the grain size is comparable with the plasma Debye length.