Head-on collision of electron-acoustic solitary waves in a plasma with superthermal hot electrons

The head-on collision between two electron-acoustic solitary waves in an unmagnetized plasma is investigated, including a cold electron fluid, hot electrons obeying a superthermal distribution and stationary ions. By using extended Poincare′-Lighthill-Kuo perturbation method, the analytical phase shifts following head-on collision are derived. Effects of the ratio of number density of hot electrons to number density of cold electrons α and superthermal parameter k on phase shifts are studied. It is found that hot-to-cold electron density ratio significantly modifies the phase shifts.