Levitation of dust in rf and dc glow discharges

We have examined the dynamics of dust in collisionless and collisional electrode sheaths of dc and rf glow discharges. The charge of the dust particles, the various forces, oscillation frequencies, damping effects and energy potential extrema are calculated. In the rf sheaths the dust particle charge is negative in the whole sheath, while in the dc sheaths the dust particle charge is positive in a major part of the sheath. Collection of dust leads to changes in the dust and plasma potentials and to a reduction in the maximum dust particle size that can be levitated. Close to the electrode there will be a dust-free zone.