Optical diagnostics of SF₆high-current discharges

Results of optical investigations of SF 6 high-current arc plasmas are presented. The experimental arrangement allowed measurements at arc currents up to 2.6 kA and at discharge pressures up to 100 kPa. The dependence of the electron density of the arc plasma on these parameters and the laser wavelength were determined using a Michelson interferometer and a Mach-Zehnder interferometer. Besides these measurements, the temperature in the arc core was determined using spectroscopic methods and the diameter of the arc was measured using an image converter camera. The results of the measurements were compared with calculated data supposing local thermodynamic equilibrium. It can be shown that there is a good agreement between the experimental and theoretical results and those of other authors.