Head-on Collisions of Two Electrostatic Solitary Waves in Electron–Positron–Ion Plasmas

In this paper, the characteristics of the head-on collision between two electrostatic solitary waves in unmagnetized electron-positron-ion plasmas are studied. The electrons and positrons are assumed to be isothermal/adiabatic and dynamic, whereas positively charged ions are considered stationary. Using the extended Poincare??-Lighthill-Kuo method, the Korteweg-de Vries equations and the analytical phase shifts after the head-on collision of two solitary waves are derived. The results show that the ion-to-electron number density ratio, and the positron-to-electron temperature ratio have strong effects on the phase shifts.