Artificial Triggered Lightning Using Ultraviolet Lasers: Guiding of the Electrical Discharges by an Excimer Laser

Guiding and triggering of the electrical discharges in lm air gaps by excimer lasers (KrF (λ=248nm), ArF (λ=193nm)) have been performed. A laser pulse (KrF: 750mJ, ArF: 550mJ) produced a plasma channel over a distance of more than 0.5m by focused with a lens. Characteristics of guided discharges along the plasma channel were investigated in detail. From these results, it is found that an excimer laser pulse can guide the positive discharges and propagate in the plasma channel produced by itself without loss. However the excimer lasers have little ability to trigger the discharges. Further the guiding ability is not maintained for a long time compared with that of infrared lasers. On the basis of these experimental results, we discussed the basic concept of the laser triggered lightning with an excimer laser.