Photoionization in precursor of laser-induced plasma by ultraviolet radiation

In the initial stage of laser-induced plasma, a laser absorption layer propagates with the shock wave that corresponds to a combustion layer in chemical detonation. The structure has been recognized as a Laser Supported Detonation (LSD). A previous study show that a precursor electron ahead of a shock wave has been investigated until LSD termination with using a two wave Mach-Zehnder interferometer 1 . Results of this study demonstrate that the laser heated sustained the LSD wave. Since laser heating induces the shock wave in the LSD, the L SD is difficult to sustain in separating the front of shock wave from the laser heating layer. The result suggests that the generation of the precursor electrons produces the preheated layer ahead of the shock wave. In other words, the precursor electrons play an important role in shock wave propagation. Besides, photoionization by Ultraviolet (UV) radiation behind the shock wave generate the electrons.