LOW-FREQUENCY MODES IN STRONGLY COUPLED DUSTY PLASMAS

The influence of strong correlations on low frequency collective modes in a dusty plasma is investigated. The dust dynamics is modeled by th e generalized hydrodynamics description. For the well known dust acous tic mode, strong correlations lead to new dispersive corrections, an o verall reduction of the frequency and phase velocity and the existence of parameter regions where partial derivative omega/partial derivativ e k<0. A novel result is the possibility of sustaining a low frequency transverse mode-a dust shear mode-in which the correlation energy act s as an effective bulk modulus. The influence of ion streaming and col lisional interaction with a background of neutrals on the modes are al so studied and it is shown that the longitudinal modes may be driven u nstable by ion streaming. (C) 1998 American Institute of Physics. [S10 70-664X(98)03610-6].