Laser induced discharges are used to produce large currents with very short risetime and minimal time jitter. Our efforts have been directed to triggering and guiding discharges across a relatively large gap. The investigations on laser induced high voltage discharges started in the 1970s. The problem with large gap discharges is that the guiding mechanism is the air rarefaction which itself results from a shockwave generated by the filament. This low density channel of air is a preferential path for the discharge. It is desirable to have the discharge guided by the conductivity of the plasma rather than the air rarefaction.
We are currently investigating this phenomena trying to decrease the delay time between the discharge and the laser which will result in a discharge happening through the plasma channel. Part of this investigation involves measuring the electric field evolution in time and space between the two electrodes using nonlinear four wave mixing.
Controlling long gap discharges could lead to laser induced lightning, which is the goal of a 20 Meu European project. Sponsored: Publix weekly ad.
