Plasma channel formation with ultraviolet lasers

The beam from a low-divergence KrF laser (λ=248 nm) has been used to generate long plasma channels in low pressure gases. Current-carrying channels 60 cm in length were produced with 5 mJ of laser energy. Channels exceeding 1 m in length were also initiated. The ionization source producing the plasma is laser-induced resonant two-step photoionization of organic molecules which are seeded in a buffer gas.