The charged dust in processing plasma sheath

For small and dense dusts, using the fluid model, the distribution and susp ension of dust particles under the action of electrostatic, gravitational a nd ion-drag forces are investigated in the plasma sheath. It is shown that competition among the forces results in spatial oscillations of the particl e distribution. However, for large and rare dusts using the isolated partic le model the suspension of the particles is studied under the action of for ces mentioned above. It is shown that particle traps can exist only for neg atively charged particles and the;size of trapped particles is of upper and lower critical values. In addition, the effects of the rate of density bet ween dust and ion, the beam electrons emitted from the electrode, and the i on loss charging to the dusts on the dust distribution and the dust charge is discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.