Effects of Landau damping on ion-acoustic solitary waves in a semiclassical plasma

Abstract: We study the nonlinear propagation of ion-acoustic waves (IAWs) in an unmagnetized collisionless plasma with the effects of electron and ion Landau damping in the weak quantum (semiclassical) regime, i.e., when the typical ion-acoustic (IA) length scale is larger than the thermal de Broglie wavelength. Starting from a set of classical and semiclassical Vlasov equations for ions and electrons, coupled to the Poisson equation, we derive a modified (by the particle dispersion) Korteweg-de Vries (KdV) equation which governs the evolution of IAWs with the effects of wave-particle resonance. It is found that in contrast to the classical results, the nonlinear IAW speed $(\lambda)$ and the linear Landau damping rate $(\gamma)$ are no longer constants, but can vary with the wave number $(k)$ due to the quantum particle dispersion. The effects of the quantum parameter $H$ (the ratio of the plasmon energy to the thermal energy) and the electron to ion temperature ratio $(T)$ on the profiles of $\lambda$, $\gamma$ and the solitary wave amplitude are also studied. It is shown that the decay rate of the wave amplitude is reduced by the effects of $H$.