Mechanism of laser-induced plasma shock wave evolution in air

A theoretical model is proposed to describe the mechanism oflaser-induced plasma shock wave evolution in air. To verify thevalidity of the theoretical model, an optical beam deflection techniqueis employed to track the plasma shock wave evolution process. Thetheoretical model and the experimental signals are found to be ingood agreement with each other. It is shown that the laser-inducedplasma shock wave undergoes formation, increase and decay processes;the increase and the decay processes of the laser-induced plasmashock wave result from the overlapping of the compression wave andthe rarefaction wave, respectively. In addition, the laser-inducedplasma shock wave speed and pressure distributions, both afunction of distance, are presented.