Spherical and Cylindrical Ion Acoustic Solitary Waves in Electron-Positron-Ion Plasmas with Non-Maxwellian Electrons and Positrons

The propagation of cylindrical and spherical ion acoustic solitary waves in a plasma system consisting of ions, electrons and positrons are investigated. The electrons and positrons are assumed to be following the nonextensive distribution popularly known as Tsallis distribution. The standard nonlinear equation i.e. Korteweg de-Vries (KdV) equation has been solved numerically using suitable mathematical transformations. The effect of nonextensivity (q) and nonplanar geometry on the amplitudes and width of ion acoustic potential structures have been studied numerically. A transition from negative to positive potential structures have been observed for the planar as well as nonplanar geometries for lower values of q in the range −1 < q < 0. Soliton amplitude is maximum for spherical waves and is minimum and for planar waves while it lies in between the two for cylindrical waves. The present investigation may help us in understanding the study of cylindrical and spherical solitary waves in astrophysical plasmas.