Laser-triggering of electric breakdown in liquids

A laser-triggering device for the study of electric breakdown in liquids is described. Triggered breakdown can be used to study the propagation of the breakdown after initiation. It is important that the triggering method used be as flexible as possible, for example, that the trigger pulse can be applied at various points in a gap and that the trigger pulse energy can be varied. Laser triggering provides such flexibility. The technique has been shown to trigger DC breakdowns for pulse energies down to about 50 mJ for 8-ns-long 1064-nm Q-switched laser pulses. It is concluded that electrical breakdown at semihomogeneous field strengths much below spontaneous breakdown can be induced by laser-produced plasmas, thereby allowing direct study of the propagation field