Sheath modification in the presence of dust particles

Negatively charged dust particles are expected to modify the local sheath potential where they are in equilibrium. In the conditions of a hot cathode discharge, sheath profiles are deduced from the measurement of ion drift velocities, with dust particles in suspension and without. In the unperturbed potential profile, the surface potential of an isolated dust particle, its charge, and its potential energy can be estimated as a function of the position in the sheath. In the presence of dust particles, an average increase of the ion drift velocity is measured showing a modification of the local sheath profile. This experimental result suggests that the dust particle charge due to the plasma particle fluxes in the sheath, modifies in turn the local plasma particle distributions. (C) 2000 American Institute of Physics. [S1070-664X(00)04911-9].