Nonlinear propagation of ion-acoustic solitons in an electron–positron–ion plasma with superthermal electrons and positrons

The nonlinear propagation of ion-acoustic solitary waves has been investigated in an unmagnetized warm plasma consisting of positive ions, superthermal electrons, and thermal positrons by using the reductive perturbation method. Only the fast compressive ion acoustic mode is found to exist in KdV solitons. The effects of the various parameters, such as the electron superthermal parameter ke, positron superthermal parameter kp, positron concentration μ, ion-to-electron temperature ratio σi, and electron-to-positron temperature ratio σp, have been presented for the KdV solitons. The presence of σi and σp has significantly altered the fundamental characteristics (amplitude and width) of ion acoustic solitons for the cases σi > σp, σi < σp, and σi = σp, which is a significant finding from our research. The findings indicate that the nonlinear coefficient is more pronounced for the higher values of σi and σp. Moreover, in the cases of σi = σp, σi > σp, and σi < σp, respectively, the solitons’ magnitudes progressively grow as the superthermal electron and positron parameters increase. This model may be helpful in highlighting the salient features in both practical applications, like fusion energy research and basic physics.