Dynamics and modelling of shock waves formed during propagation of a laser-supported detonation wave in argon

Experimental and theoretical investigations are reported of axial and radial shock waves formed in argon during propagation of an optical detonation wave maintained by a CO$_2$ laser pulse. The experimental results are not be described by the standard self-similar law of motion of a cylindrical shock wave, but instead they agree well with the results of self-consistent two-dimensional numerical calculations. This is attributed to displacement of a hot gas along the beam axis out of the zone of absorption of laser radiation. The distance $R$ travelled by the front of the resultant radial shock wave during a time interval $t$ is described by the law $R\propto t^\alpha$, where $0.5<\alpha<0.65$.