LAUSR

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 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 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 ( λ ) and the linear Landau damping rate ( γ ) 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 λ, γ, and the solitary wave amplitude are also stu...