LAUSR

The nonlinear propagation of ion-acoustic (IA) waves (IAWs) in a four component plasma medium (FCPM) containing inertial warm positive ions, and inertialess iso-thermal cold electrons as well as non-extensive ($q$-distributed) hot electrons and positrons is theoretically investigated. A nonlinear Schrodinger equation (NLSE) is derived by using the reductive perturbation method, and it is observed that the FCPM under consideration supports both modulationally stable and unstable parametric regimes which are determined by the sign of the dispersive and nonlinear coefficients of NLSE. The numerical analysis has shown that the maximum value of the growth rate decreases with the increase in $q$ ($q>1$), and the modulationally unstable parametric regime allows to generate highly energetic IA rogue waves (IARWs), and the amplitude and width of the IARWs increase with an increase in the value of hot electron number density while decrease with an increase in the value of cold electron number density. The applications of our investigation in understanding the basic features of nonlinear electrostatic perturbations in many space plasma environments and laboratory devices are briefly discussed.