Head-on collision of ion-acoustic solitary waves in a Thomas–Fermi plasma containing degenerate electrons and positrons

Head-on collision between two ion acoustic solitary waves in a Thomas–Fermi plasma containing degenerate electrons and positrons is investigated using the extended Poincaré–Lighthill–Kuo (PLK) method. The results show that the phase shifts due to the collision are strongly dependent on the positron-to-electron number density ratio, the electron-to-positron Fermi temperature ratio and the ion-to-electron Fermi temperature ratio. The present study might be helpful to understand the excitation of nonlinear ion-acoustic solitary waves in a degenerate plasma such as in superdense white dwarfs.