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

Electron densities and ion (gas) temperatures on the axis of an are dischar ge 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 ma in plasma parameters is based on line shape measurements, the ion temperatu re on the Doppler broadening of selected ArII lines, while the electron den sity on the Stark broadening of the hydrogen H-beta line which appear in th e spectrum due to hydrogen traces in the applied gases. The significance of reliable plasma diagnostics for determination of atomic structure data is discussed.