Ion-acoustic envelope excitations in electron–positron–ion plasma with nonthermal electrons

Abstract

A theoretical investigation has been made for modulational instability of ion-acoustic waves in an electron–positron–ion plasma with nonthermal electrons. Employing reductive perturbation method (RPM), the nonlinear Schrödinger equation (NLSE) is derived. The dispersive and nonlinearity coefficients, P and Q, respectively, are the functions of nonthermal parameter ( β), ratio of positron to electron density ( d), ratio of the electron to positron temperature ( δ) and ratio of ion to electron temperature ( σ). It is observed that these parameters significantly modify the conditions of the modulational instability. The system supports both types of bright and dark envelope excitations.