Effects of suprathermal particles on the dust ion-acoustic waves in a complex plasma

Dust ion-acoustic waves propagating in a complex plasma containing dusty particles and suprathermal electrons and ions are kinetically analyzed. The suprathermal particles are effectively modeled by the Lorentzian (kappa) velocity distribution function. For a collisionless and unmagnetized plasma, the full spectrum of the dispersion relation is obtained and the suprathermal particle effects on the wave frequency and the Landau damping are investigated. For a given wave number, the wave frequency decreases as the spectral index kappa decreases, especially very rapidly in the low kappa region. The Landau damping of the wave and its maximum are derived. They are found to be enhanced by the increase of suprathermal particles. The ion-to-electron density ratio also enhances the damping rate greatly. (C) 2010 Elsevier B.V. All rights reserved.