Results from the Opacity-on-the-National Ignition Facility Project: Comparison of Simulated and Experimental Opacities

Los Alamos and Livermore National Labs are engaged in a series of experiments on the National Ignition Facility (NIF) to produce opacity data for iron and oxygen at conditions of 150 to 180 eV and 0.7 to 3.0 x 10²² electrons/cm³. The experiments on the NIF aim to resolve a long-standing discrepancy between experimental data from the Z-machine and modern theoretical opacity calculations. The results could also impact models for the base of the Solar convection zone. Forward modeling of the experiment is important for characterizing backgrounds, interpreting the experimental results, and predicting the benefit of the time-gated spectroscopy over time-integrated. Here we report on initial simulations of opacity-on-NIF samples of O:Mg:Si inside the hohlraum using the radiation-hydrodynamic code CASSIO utilizing multigroup radiation transport. The simulations have been post-processed with time dependence to determine how the desired spectral features of the sample compare with the background noise within the hohlraum.