Planar sheath model in dusty plasmas with a two-temperature electron distribution

The two-temperature electron distribution is found to affect significantly the dust grain surface potential or the dust grain charge. Based on the Sagdeev potential approach, a modified sheath criterion including the effect of a two-temperature electron distribution is established theoretically. A one-dimensional fluid model is utilized to describe the sheath at a plasma-wall boundary in dusty plasmas with a two-temperature electron distribution. The effects of the population ratio of hot to cold electrons and of the temperature ratio of hot to cold electrons on the characteristics of the dusty plasma-plane wall (or probe) boundary are investigated. The spatial distributions of the electric potential and of the velocities and densities of the plasma species including those of dust grains, the electric force, and the ion drag force are calculated. With increasing population ratio of hot to cold electrons, the sheath width broadens, and the ion flux to the wall increases whereas the ion drift velocity decreases. An enhanced temperature ratio of hot to cold electrons causes the sheath width to broaden and the ion flux to the wall to increase.