Effects of the laser-plasma production position on laser-induced discharge under non-uniform electric field

Experiments and a simulation are carried out to study the mechanism of laser-induced discharge under nonuniform DC electric field made by plane-needle electrode gap. The laser-plasma is affected by the applied electric field and the shock wave generated by the plasma at the time-scale less than a few microseconds from the time of laser irradiation. It takes, however, the order of 100 micro-seconds to have the flashover of the electrode gap. The results indicate that the laser-induced discharge occurs only after the leader is formed at the needle electrode and works as an extension of the electrode