Characterization of the Initial Stage of Discharges between Micro-gap in Liquid using Optical Measurement

Abstract

The pulsed arc discharges in liquid between a micro-gap composed of a tungsten wire and a copper rod were characterized for the application to electrical discharge micro-machining. We discussed the spark formation and optical emission spectral lines of micro-gap discharge in liquid. The discharge time lag depends on the breakdown process and discharge position on the surface of the plate electrode. Intense broadband continuum radiation was observed during the pulsed discharge before which clear spectral lines appeared. The excitation temperature of copper atom was obtained using the spectral lines.