Electron density determination in a MgFe dense plasma via Stark-broadening analysis*

Recent measurements of L-shell Fe opacity at temperatures above 100eV were performed at Sandia National Laboratories by recording x-ray transmission through a MgFe two-element plasma. While the observation of line absorption in Fe L-shell transitions was an important goal of the experiment, the Stark-broadened line absorption in Mg K-shell transitions provided an independent spectral signature for electron density determination. Indeed, at the expected 10$^{21}$ cm$^{-3 }$to 10$^{22}$ cm$^{-3 }$electron density range, Stark-broadening dominates the line width of several Mg K-shell transitions. We discuss the Mg K-shell line absorption spectrum, the calculation of Stark-broadened absorption line shapes, and their application to data analysis and electron density extraction.