Experimental and theoretical Stark broadening studies of the hydrogen Paschen beta line.

Abstract

Experimental and theoretical Stark broadening studies of the Paschen beta line of hydrogen (lambda=1.28 microm) are reported. Line shape measurements were performed at electron densities of the plasma between 3.5 x 10(15) cm(-3) and 7.5 x 10(15) cm(-3), applying as the light source a wall-stabilized arc operated at atmospheric pressure in a helium-hydrogen gas mixture. The radiation of the plasma, emitted from nearly homogeneous plasma layers in the end-on direction, was registered with the use of a grating spectrometer equipped with a charge coupled device detector. The measured light outputs were calibrated against signals obtained from a tungsten strip radiation standard. The experimentally determined line profiles are compared with results of new Stark broadening calculations based on simulation techniques. The measured broadening, shift, and asymmetry parameters are also compared with results of previous Stark broadening calculations and other experimental data obtained at electron densities higher as well as lower than ours.