Comprehensive Experimental Study on Vacuum Breakdown Phenomenon through Plasma Flare Expansion, Fusion and Deconstruction Process

The development of high-voltage vacuum circuit breakers requires a fundamental knowledge of the vacuum breakdown phenomenon including plasma flare expansion, fusion and deconstruction processes. However, few experimental results are available in literature with the exception of flare expansion speed, and the flare behaviours have never been fully understood. In this paper, we describe self-consistent characterisation of the plasma flare behaviours achieved using various optical techniques including Shack-Hartmann type laser wavefront sensors for two-dimensional electron density imaging, a laser absorption method for plasma temperature measurement, high-speed framing photography for speed determination of flare expansion and optical emission spectroscopy for plasma composition assessment.…