Laser triggered discharge gap

For vacuum discharge gap with ignition by plasma of the electric spark it is demonstrated that there is insufficiency of the possibilities to control duration of the commutation delay time by variation of spark energy. For vacuum discharge gap with ignition by lazer plasma it is discovered that there is a threshold value of the radiation energy. Excess of this level changes the nature to delay time dependency from the radiation energy. The value of the threshold radiation energy is defined by thermodynamic parameters of the cathode material. On the basis of the experimental data the following suggestion is brought forth. Under the action of laser pulse radiation in the beginning a glowing discharde takes place in products of the electrode erosion and then as a result of ionization-overheating instability it suffers the contracting of the current channel and moves over to arc.