Experimental study of a SF6arc plasma at atmospheric pressure

The local parameters of an arc plasma in SF 6 at atmospheric pressure have been measured in the stationary state and during the plasma decay. Classical spectroscopy methods have been used (relative and absolute line intensities; Stark broadening of lines), and two-wavelength laser interferometry has been adapted for measuring the electron density in a SF 6 plasma. There exists a collisional equilibrium for sulphur. Demixing has a negligible influence on the plasma state in the authors' experimental conditions.