Study of Dusty Plasmas

This progress report describes research work performed at Texas Tech University under AFOSR Grant No. F49620-97-1-0007 during the period of November 1,1996 to October 31, 1999. Theoretical and computational study of collective effects in dusty plasmas revealed 1 formation of oscillatory wake potential behind a highly charged dust grain placed in the ion flow in the sheath, 2 stable polygon structures formed by a collection of trapped dust particulates in the wake potential minima, 3 low frequency oscillations of order 10Hz associated with the polygon plasma crystal structure, 4 interaction of dust particulates and plasma particles through Hamiltonian formulation, 5 low frequency lattice oscillations 1 Hz described by Hamiltonian formulation, 6 The attractive interaction between dust particulates through exchange of phonons, 7 polarization of a dust grain in the order of a Debye length, 8 the higher threshold of the dust ion-acoustic instability with the effect of dust-charging process, and 9 Buneman-type streaming instability in a dust plasma developed in a subsonic ion flow.