Opacity measurements in a hot dense medium

The first measurements of the opacity in a well characterized, hot, dense, laser-produced plasma are reported. Measurements of the absorption of x rays by 1 to 2 transitions in Al xii through Al viii have been made in a laser heated slab plasma at the measured temperature and density of 58±4 eV and 0.020±0.007 g/${\mathrm{cm}}^3$. The conditions in the plasma were determined to be reproducible, spatially uniform, and in nearly complete local thermodynamic equilibrium. The absorption spectra and the temperature-density data obtained provide an improved means for comparison with detailed atomic physics and opacity calculations.