Landau-damped dust-acoustic solitary waves in nonthermal plasmas

We utilize a fluid kinetic hybrid approach to analyze dust acoustic wave propagation in collisionless, unmagnetized dusty plasmas, specifically investigating how linear Landau damping effects in the ion population affect weakly nonlinear and weakly dispersive wave behavior. An electron-depleted plasma is considered, consisting of a cold fluid of negatively charged dust particles and two types of ions at different temperatures, modelled by a kappa-type distribution. Anticipating nonlinear solitary waves, a reductive perturbation technique is employed, leading to a nonlinear partial differential equation for the electrostatic potential in the form of a modified Korteweg–de Vries (mKdV) equation, featuring an additional term to account for linear Landau damping of the ions. The solitary wave's amplitude is found to decay with time. A parametric analysis is carried out of the impact of the plasma configuration on the Landau damping rate under the influence of this latter (Landau damping-related) term. The results of this work are highlighted in space plasma, such as that around Enceladus and Saturn's E ring, where the occurrence of Landau damping in combination with a nonthermal ion distribution may affect wave propagation significantly.