Nonlinear coupling of Langmuir and electron acoustic waves in a viscous plasma

Abstract

A nonlinear analysis of finite amplitude electron acoustic waves is considered in a viscous plasma. The two fluid two time scale model is used to describe the two temperature electron species in a fixed ion background. We have obtained two sets of modified Zakharov equations where the modification comes due to the presence of viscosity in the plasma system. We have shown that, for very low frequency, these viscosity modified Zakharov equations reduce to a modified nonlinear Schrödinger's equation where viscosity introduces a new term via collective effects. Perturbative analysis shows the formation of soliton structures with an oscillating tail. The relevance of the results is important in the context of astrophysical and laboratory plasma.