Experimental study of the laser-triggered discharge for the application in a gap switch

Laser triggering is interesting for gap switches used in power systems and pulsed power because of its well-controllable delay and jitter time, as well as its electrically uncoupled characteristics. Despite the large attention that was paid to various parameters affect triggering characteristics, the underlying physics of laser triggering remain unclear. In this paper, the nanosecond-laser-triggered pulsed discharge was investigated in atmospheric air. Using a picosecond laser, a high-time-resolution interferometer was constructed and the laser-and discharge-produced plasmas were detected. The shockwaves formed by instantaneous release of the laser and electrical energy into the ambient air were well distinguished. Using the interferograms, phase-shift maps were extracted by a 2-D fast Fourier transform method. Finally, preliminary experiments were performed on laser-triggered discharge from a prototype gap switch, and delay and jitter results were given.