Modulational instability of ion acoustic waves in e-p-i plasmas with electrons and positrons following a q-nonextensive distribution

The propagation of ion acoustic waves (IAWs) in plasmas composed of ions and nonextensive electrons and positrons is investigated. By means of the reduction perturbation technique, a nonlinear Schrödinger equation is derived and the modulation instability (MI) of ion acoustic waves is analyzed in detail. The effects of different ranges of the nonextensive parameter q on the MI are studied. The growth rate of the MI is also given for different values of the q parameter. It is also found that the ratio of the electron temperature to positron temperature and the ratio of the positron density to electron density modify the nature of IAWs instability and the solitary structures.