Effect of Dust Charge Inhomogeneities on Electrostatic Waves over Arbitrary Fugacity Range

Abstract

The linear propagation of dust-acoustic waves and dust-Coulomb waves in a dusty plasma comprising electrons, ions and dust grains, having gradients in the equilibrium dust charge and number densities, are studied by self–consistently including the grain charge fluctuations. Using the standard current balance equation to model charge fluctuation effects, the linear dispersion relation is derived and examined in the limit of low and high fugacity, f, respectively. It is shown that for both the dust-acoustic and dust-Coulomb waves the phase speeds are unaffected by weak dust charge and number density gradients. However, the amplitudes of the dust-acoustic and dust-Coulomb waves are both sensitive to dust charge and number density gradients and scale differently with regards to each of these gradients.