抄録
Characteristics of electrical discharges triggered by a high power KrF or ArF excimer laser were studied to investigate fundamental mechanisms of a laser-induced discharge. Experiments were done in the different kind of ambient gases (air, N2, O2 of 100-1000mb in pressure) under an uniform DC electric field using Rogowski electrodes. Electrical characteristics such as 50% flashover voltage, an initial current due to a laser-produced plasma and a delay time from a laser incidence to a flashover were measured. Also optical measurements, such as a streak image of a flashover, transmittance of a laser light in gases, and temporal and spatial spectral emissions from molecular, atomic, and ionic species of O2 and N2 were carried out. It was found that oxygen molecules play an important role in characteristics of a laser-initiated discharge.
