Nonplanar Ion Acoustic Solitary Waves in Electron-Positron-Ion Plasma With Warm Ions, and Electron and Positron Following Q-Nonextensive Velocity Distribution

Cylindrical and spherical modified Korteweg-de Vries equations are derived for ion-acoustic solitary waves (IASWs) in an unmagnetized, collisionless electron-positron-ion plasma consisting of warm ion fluid and
q
-nonextensive distributed electrons and positrons by using standard reductive perturbation method. The effects of nonplanar geometry, nonextensivity of electrons and positrons, and other plasma parameters on nonlinear dynamics of cylindrical and spherical IASWs are studied numerically. Numerical results indicate that the amplitude of the soliton is large in spherical geometry in comparison with cylindrical geometry, and both the electron and positron nonextensive parameter has a significant effect on the structure of the nonplanar IASWs.