Spectroscopic absorption measurements of an iron plasma

The first quantitative measurement of photoabsorption in the region determining the Rosseland and Planck mean opacities is obtained for a well- characterized, radiatively heated iron plasma using new techniques and instrumentation. The plasma density and temperature are simultaneously constrained with high accuracy, allowing unambiguous comparisons with opacity models used in modeling radiative transfer in equilibrium astrophysical and laboratory plasmas. The experimental Rosseland and Planck group means are constrained to an accuracy of 15 percent. (Author)