Diagnostics of helium-argon arc discharge plasma based on special line shape measurements

Electron densities and ion (gas) temperatures on the axis of the arc discharge plasma, produced at atmospheric pressure in a gas mixture of 95% helium and 5% argon, are determined at two arc currents. The evaluation of both main plasma parameters is based on line shape measurements, the ion temperature on the Doppler broadening of selected ArII lines, while the electron density on the Stark broadening of the hydrogen Hβ line which appear in the spectrum due to hydrogen traces in the applied gases. The significance of reliable plasma diagnostics for determination of atomic structure data is discussed. (author)