Two-dimensional electron density characterisation of arc interruption phenomenon in current-zero phase

Two-dimensional electron density imaging over free burning $S{F}_6$ arcs and $S{F}_6$ gas-blast arcs was conducted at current zero using highly sensitive Shack–Hartmann type laser wavefront sensors in order to experimentally characterise electron density distributions for the success and failure of arc interruption in the thermal reignition phase. The experimental results under an interruption probability of 50% showed that free burning $S{F}_6$ arcs with axially asymmetric electron density profiles were interrupted with a success rate of 88%. On the other hand, the current interruption of $S{F}_6$ gas-blast arcs was reproducibly achieved under locally reduced electron densities and the interruption success rate was 100%. (paper)