Shack–Hartmann type laser wavefront sensor for measuring two-dimensional electron density distribution over extinguishing arc discharge

Abstract

Shack–Hartmann type laser wavefront sensors were developed for measuring a two-dimensional electron density distribution over an arc channel in an extinguishing phase by only a single measurement with high temporal and spatial resolutions. The sensors were applied to pulsed arcs in a 3 mm air gap between rod-to-rod tungsten electrodes with a diameter of 1mm. Electron densities in the arc discharges with currents of several tens of amperes were 2 × 1023 m−3 around the gap centre, which were more than twice lower than those near the anode and cathode.