Jeans instability in a complex plasma in the presence of negative ions

Abstract

General fluid dispersion relations for the Jeans instability in a complex plasma have been derived in two cases. (i) Electrons, positive ions and negative ions are all Boltzmann distributed and dust grains are cold and inertial. (ii) Electrons are Boltzmann distributed, positive ions and negative ions are inertial and dust grains are streaming. In both cases grain charge fluctuations are considered. Both the dispersion relations show that presence of negative ions reduces the threshold of the Jeans instability in the complex plasma system. The streaming motion of dust grains is responsible for the development of an unstable mode which is not purely growing.