Electrical and Optical Properties of High-Pressure Argon Plasma

Argon plasma has been investigated in the pressure range p ¿ 200 bar and at temperatures up to 13 000 K. The experiments were performed by using a wall-stabilized arc in an uncooled copper cascade. The measured electrical conductivity agrees with theoretical predictions based on the unified theory. Line and continuous intensities, as well as width and shift of the Ar I line at ¿ = 696.5 nm, were determined. A set of optimized atomic constants for these radiative processes was obtained by a newly developed multiple approximation method. While linewidth due to Stark and Van der Waals broadening are in fair agreement with theory, the line shift has to be corrected.