Instability of a dusty plasma in the presence of a dc electric field and an equilibrium dust charge gradient

It is shown that a dusty plasma becomes unstable when a de electric field and an equilibrium dust charge gradient are simultaneously present. Physically, the instability arises because the de electric force as well as convection of the dust charge gradient produce dust charge fluctuations which cannot keep in phase with the potential of electrostatic fluctuations. This novel instability associated with the delayed dust charging can explain the salient features of that instability which is observed by Nonumura et al. [Phys. Rev. Lett. 83 (1999) 1970] near the sheath boundary in a dusty plasma. (C) 2000 Elsevier Science B.V. All rights reserved.