Transition from steady-state to pulsed gas breakdown near the surface of a target subjected to laser radiation

An experimental investigation was made of the transition from steady-state to pulsed ionization–thermal breakdown of gases near the surface of a target irradiated by a laser. It was found that when the laser beam power was varied, the target temperature at the moment of formation of a plasma near its surface fell to a minimum at some moment from the beginning of irradiation but before breakdown. A study was made of the dependence of this time of onset of steady-state breakdown on the size of the irradiated spot and on the thermophysical properties of the gas.