The competition between the light and thermal pressures in laser-irradiated plasmas

Shock generation by the ablation of laser-heated plasma into vacuum and the boring of ultra-intense laser into plasma is studied using rocket model and pistol model, respectively. It shows that the hydrodynamic behavior of laser-irradiated plasma depends on the competition between the light and thermal pressures, and in both processes a density jump at the critical surface as well as an inward propagating shock will be induced. The fluid parameters characterizing the processes are derived and expressed as functions of the ratio of light and thermal pressure.