Ion-acoustic shock waves and their head-on collision in a dense electron-positron-ion quantum plasma

Ion-acoustic shock waves and their head-on collision in a dense quantum plasma comprised of electrons, positrons, and ions are studied. The extended Poincaré-Lighthill-Kuo perturbation method is used to derive the Korteweg-de Vries-Burgers equations for shock waves in this plasma. The dissipation is introduced by taking into account the kinematic viscosity among the plasma constituents. The effects of the ratio of positrons to ions unperturbation number density μ, the normalized kinematic viscosity ηi0, and the quantum Bohm potential H on the interaction and structure of the shock waves are investigated. It is found that there are integrally vertical downward movements for both the colliding shocks after their head-on collision, but there are no shifts of the postcollision trajectories (phase shifts). It is also found that these plasma parameters can significantly influence the collision and properties of the colliding shocks. The results may have relevance in dense astrophysical plasmas (such as neutron stars or white dwarfs) as well as in intense laser-solid density plasma experiments.