THE INFLUENCE OF DUST PARTICLES ON ELECTROMAGNETIC ION-CYCLOTRON WAVES IN A BI-LORENTZIAN PLASMA

The influence of dust particles on electromagnetic ion cyclotron (EMIC ) waves, propagating parallel to the magnetic field, in a plasma where the hot ions are modelled by a bi-lorentzian or Kappa distribution ha s been studied. The electrons and dust particles have been treated as cold. Expressions for the dispersion relations and growth/damping rate s in both high- and low-beta plasmas have been derived. For the low-be ta case temperature anisotropy is the source of instability in an elec tron-ion plasma. This instability is strongly influenced by the temper ature anisotropy of the hot ions and the charge and density of the dus t particles; the instability increases with these parameters. However, in high-beta plasmas, the instability is driven by the dust. The grow th rate increases with the charge on the dust; but with increasing dus t densities the EMIC wave propagates almost freely. (C) 1997 American Institute of Physics.