Ion contribution to the astrophysical important 447.15, 587.56 and 667.82 nm He I spectral lines broadening

Abstract

Characteristics of the astrophysical important Stark broadened 447.15 nm, 587.56 nm and 667.82 nm He I spectral line profiles have been measured at electron densities between 0.3 × 1022 and 8.2 × 1022 m-3 and electron temperatures between 8000 and 33 000 K in plasmas created in five various discharge conditions using a linear, low-pressure, pulsed arc as an optically thin plasma source operated in a helium-nitrogen-oxygen gas mixture. On the basis of the observed asymmetry of the line profiles we have obtained their ion broadening parameters (A) caused by influence of the ion microfield on the line broadening mechanism and also the influence of the ion dynamic effect (D) on the line shape. Our A and D parameters represent the first data obtained experimentally by the use of the line profile deconvolution procedure. We have found stronger influence of the ion contribution to these He I line profiles than the semiclassical theoretical approximation provides. This can be important for some astrophysical plasma modeling or diagnostics.