Fast imaging of the laser-blow-off plume driven shock wave: Dependence on the mass and density of the ambient gas

A systemic investigation of expansion dynamics of plasma plume, produced by laser-blow-off of LiF–C thin film has been done with emphasis on the formation of shock wave and their dependence on the pressure and nature of the ambient gas. The present results demonstrate that highly directional plume produces a strong shock wave in comparison to shock produced by the diverging plume. Shock-velocity, strength and its structure are strongly dependent on ambient environment; maximum shock velocity is observed in helium whereas shock strength is highest in argon environment. The role of chemically reactive processes was not observed in the present case as the plume structure is almost similar in argon and oxygen.

► Highly collimated, low diverging plume produces a strong shock wave.
► Plume structure is almost similar in Ar and O2 environment.
► Role of chemically reactive processes is not observed in the present case.
► Shock front is completely detached from the plasma plume in He gas.
► Second intensity discontinuity just behind the shock front is observed in Ar and O2.