Plasma diagnostics based on self-reversed lines—II. Application to nitrogen, carbon and oxygen arc measurements in the vacuum ultraviolet

Abstract

A numerical model, which describes the formation of spectral lines by solving the equation of radiative transfer, has been applied to several self-reversed lines of nitrogen, carbon and oxygen in the spectral range between 115 and 200 nm using a wall-stabilized arc as a radiation source. The model calculation takes into account diffusion and demixing of the plasma components. By comparing measured with calculated line shapes, information is obtained on both the temperature distribution of the plasma column and the transition probabilities and Stark constants of the lines. Quasistatic braodening due to ion interaction and, especially, foreign-gas interaction are found to play a major role in line-wing formation.