Shack-Hartmann Type Laser Wavefront Sensor for Measuring Electron Density in Low Current Arc

To know electron densities in low current arcs, Shack-Hartmann type laser wavefront sensor was developed, improved in terms of measurement accuracy, and applied to atmospheric arcs with a peak current of 0.8kA. An electron density in pre-extinguishing phase was 5×1023m-3 at gap centre when an instantaneous current decreased to 0.1kA.