Dispersion properties of dusty plasmas

The presence of charged dust particles in a plasma can change its dispersion properties. From the linear response of an equilibrium dusty plasma to the propagation of small perturbations, we find an average dielectric function є(ω, k) for the system in the case when the grain space distribution is random, and ensemble averages are taken over the random variables. For the case of high-frequency plasma waves, when ε ≈ 1-ω²_p/ω² for the unperturbed case (cold plasma), we find that є becomes complex in the presence of the dust, leading to possible damping in a domain where Landau damping is usually negligible (ω » kV_T).