Landau damping of dust acoustic waves in a Lorentzian plasma

Abstract

The Landau damping of dust acoustic waves propagating in a dusty plasma modeled by a Lorentzian (kappa) distribution for electrons and ions, and by a Maxwellian distribution for the dust grains is kinetically investigated. The dust acoustic waves are found in the range of kv(d)<omega < kv(i)< kv(e), where v(alpha) is the thermal velocity of species alpha(=i,e,d). The damping rate is shown to be dependent on the spectral index kappa as well as the ratio of ion density to electron. The maximum Landau damping rate is derived and found to be approximately 0.2 sigma(kappa)omega(pd) where omega(pd) is the dust plasma frequency and sigma(kappa) is a kappa-dependent factor, which has the maximum value of 1.33 (for the smallest kappa) and reduces to unity as the nonthermal effect disappears.