Iron Opacity Measurements on the National Ignition Facility (NIF)

The opacity of iron helps regulate the transfer of energy out from the center of the sun, particularly at the radiative-convective zone boundary at temperatures between 150 and 200 eV. Recent experiments at Sandia National Laboratory's Z machine have shown as much as a factor of two discrepancy between calculated and measured iron opacities. To reconcile this discrepancy a platform for measuring iron opacities at solar conditions has been developed on the NIF. Initial measurements on iron opacities have been obtained at temperatures of about 150 eV. The temperature and density of the iron plasma have also been measured. The accuracy of the measurements and a comparison to results from Z will be presented. Plans for extending the measurements to higher temperatures will also be discussed.