Collisional-radiative Calculation of the He I Line Emission Spectrum Taking into Account the Radiation Trapping Effect

Abstract

We performed collisional-radiative calculations to determine the line intensity ratios of the He I transition emission spectrum as a function of the electron density by using the collisional-radiative model taking into account the radiation trapping effect. The radiation trapping effect was estimated by using the optical escape factor on the assumption that the spatial distribution of ground-state atoms was given by a Gaussian function. Three line intensity ratios of 504.8 nm/471.3 nm, 492.2 nm/471.3 nm, and 492.2 nm/504.8 nm were calculated and compared with the results calculated using the Ballance model in which the radiation trapping effect is not included.