Ion-acoustic solitary excitations in a two-electron-temperature plasma with adiabatic warm ions: Oblique modulation

Theoretical and numerical studies are given for the amplitude modulation of ion-acoustic waves (IAWs) in a plasma consisting of two types of electrons (cold and hot) and adiabatic warm ions. Perturbations oblique to the carrier IAW propagation direction have been investigated. The stability analysis, based on a nonlinear Schrodinger equation reveals that the IAW may become unstable; the stability criteria depend on the angle theta between the modulation and propagation directions. Different types of localized IA excitations are shown to exist. The inclusion of adiabatic finite ion temperature, as compared to the cold ion model, allows for bright type solitary excitations, yet generally favors IAW stability and dark and gray envelope solitons.