Low-frequency electrostatic dust-modes in a strongly coupled dusty plasma with dust charge fluctuations

Abstract

Low-frequency electrostatic dust-modes are theoretically investigated accounting for dust grain charge fluctuation and for equilibrium grain charge inhomogeneity in a strongly coupled dusty plasma. A new stable extremely low-frequency mode, which is due to the inhomogeneity in the equilibrium dust grain charge, is found to exist in such a dusty plasma. It is also found that the dust-acoustic mode becomes unstable due to the effect of this equilibrium dust grain charge inhomogeneity. It is observed here that the influence of strong correlations in the dust fluid significantly modify the dispersion properties of this new mode as well as of the existing dust-acoustic mode. The implications of our results to recent experimental observations and to some space and astrophysical situations are briefly discussed.