Bohm criterion for a plasma composed of electrons and positive dust grains

An investigation is presented of a collisionless sheath of a dusty plasma whose constituents are positively charged dust grains and electrons. Accounting for the Boltzmann electron density distribution and the hydrodynamic dust fluid model, supplemented by Poisson and dust charging equations, a space-charge sheath model is developed. The Bohm criterion for a dusty plasma system with electrons and positive dust grains is deduced. The results can have relevance to space and laboratory plasmas.