Head-on collision of ion-acoustic solitary waves in a weakly relativistic electron–positron–ion plasma

The head-on collision of two ion-acoustic solitary waves in a weakly relativistic electron–positron–ion plasma is studied. By using the extended Poincaré–Lighthill–Kuo perturbation method, we obtain the KdV equations, the analytical phase shifts and the trajectories after the head-on collision of two solitary waves in this three-component plasma. The effects of the ratio of electron temperature to positron temperature, the ratio of the number density of positrons to that of electrons and the relativistic factor on the phase shifts are studied. It is found that these parameters can significantly influence the phase shifts of the solitary waves. Moreover, there are compressive solitary waves in such a system.