Transverse perturbation on three-dimensional ion acoustic waves in electron–positron–ion plasma with high-energy tail electronand positron distribution

The basic features of nonlinear ion acoustic(IA) waves are theoretically studied in a superthermalelectron–positron–ion (e–p–i) plasma with weakly transverseperturbation. A three-dimensional Kadomtsev–Petviashvili(KP) equation governing evolution of weaklynonlinear IA waves is derived by means of a reductiveperturbation method. The energy integral equation is usedto study the existence domain of the localized structures. Itis found that deviation from thermodynamics equilibriumincreases the existence domain of solitary solution and alsomakes the IA solitary structure more spiky. The ion concentrationhas an important effect on the existence domainof solitary solution, as for low ion density the primitivedomain reduces significantly.