Measurements of stark-broadening in hot dense plasma

We have performed high-resolution measurements of the Stark-broadened line profiles in a magnesium plasma at known density, and compared the measured line profiles with theoretical predictions. In the experiment, a magnesium sample was heated indirectly by x rays from laser-produced plasma. Both the lateral expansion of the exploding foil and the absorption in the helium-like Rydberg series were measured through the use of point projection spectroscopy. The plasma temperature and ionization distribution were determined from the ratio of the helium-like to lithium-like absorption features. For this experiment, a comparison between plasma density derived directly from radiography and by careful examination of Stark profiles was accurate to order 40 percent. The experiment will be repeated under more carefully controlled conditions which should allow a calibration of Stark-broadened profiles with an accuracy of order 10 percent.