Guiding of electrical discharges under atmospheric air by ultraviolet laser-produced plasma channel

Guiding and triggering of electrical discharges in 0.34 m air gaps by an ultraviolet laser-produced plasma have been demonstrated, An ultraviolet laser pulse (KrF laser, wavelength=248 nm, energy=750 mJ) produced the plasma channel by focusing lens with a focal length of 1 m. This plasma channel forms a straight discharge channel along the laser beam (guiding ability) and reduces the flashover voltage (triggering ability). We measured the guiding and triggering ability of the laser-produced plasma channel and estimated the state of the plasma channel by calculating the rate equations. From these experiments and simulations, we found that the guiding ability of the ion plasma is mainly due to the formation of the leader from the plasma channel by enhancement of the local fields. The guiding ability of the electron-ion plasma is different from that of the ion plasma. (C) 1996 American Institute of Physics.