Face to Face Collisions of Ion Acoustic Multi-Solitons and Phase Shifts in a Dense Plasma

This work investigates the interactions among ion acoustic (IA) single- and multi-soliton and their corresponding phase shifts in an unmagnetized plasma composed of degenerate electrons, positrons, and positive ions. Two-sided Korteweg-de Vries (KdV) equations are derived by employing the extended Poincare-Lighthill-Kuo (PLK) method for the stretched coordinates. The single- and multi-soliton solutions of the KdV equations are constructed by using the Hirota's method. The phase shifts are determined for two-, four-, six-, and eight-IA scattering solitons. The effect of positron concentration on electrostatic IA resonances due to the interactions among solitons and their corresponding phase shifts are investigated.