Theoretical analysis of planar and non-planar electron - acoustic shock waves in electron-positron-ion plasma

The propagation properties of planar and non-planar electron acoustic shock waves composed of stationary ions, cold electrons, and q-non-extensive hot electrons and positrons are studied in unmagnetized electron-positron-ion plasma. In this model, the Korteweg-de Vries Burgers equation is obtained in the planar and non-planar coordinates. We have investigated the combined action of the dissipation, non-extensivity, density ratio of hot to cold electrons, concentration of positrons, and temperature difference of cold electrons, hot electrons, and positrons. It was found that the amplitude of shock wave in e-p-i plasma increases when the positron concentration and temperature increase. The same effect is observed in the case of kinematic viscosity eta. Furthermore, it is noticed that spherical wave moves faster in comparison to the shock waves in cylindrical geometry. This difference arises due to the presence of the geometry term m/2 tau. It should be noted that the contribution of the geometry factor comes through the continuity equation. Results of our work may be helpful to illustrate the different properties of shock wave features in different astrophysical and space environments like supernova, polar regions, and in the vicinity of black holes.