Analytical description of absorption profiles in warm dense plasmas: Discussion of the non-overlapping-line limit

This paper is devoted to a theoretical description of the spectral absorption in warm dense plasmas, such as those involved in hohlraum-based opacity measurements. Dealing with complex spectra, when the effect of natural and experimental broadening, optical thickness and line overlap are taken into account, the calculation of plasma transmission becomes quite intricate. Taking as a working hypothesis a large experimental broadening, simple analytical formulas are obtained for this transmission. The formulas are checked by comparison to the exact convolution of various detailed spectra with a broadening profile. The current numerical method is then applied to the computation of transmission in Fe and Br plasmas, where opacity and line-overlap effects may be substantial.