Progress Toward Oxygen Opacity Measurements at Solar Interior Conditions on the National Ignition Facility*

The opacity campaign at the Lawrence Livermore National Laboratory (LLNL) National Ignition Facility (NIF) is in the process of measuring the soft x-ray opacity of oxygen at Solar interior conditions. These experiments are investigating a theorized solution to the Solar Problem, which, among other things, describes the discrepancy between the modeled and the helioseismically measured depth of the Solar convection zone boundary (CZB). The Solar Problem could be resolved if the theoretical Rosseland mean opacity near the CZB were increased by approximately 15 percent. Previous measurements on the Sandia National Laboratories (SNL) Z Facility (Z) show significantly higher opacity for iron than leading theoretical opacity codes near CZB conditions, accounting for approximately half of the discrepancy. The result prompted an opacity campaign at the NIF to verify the experimental results, as well as joint campaigns at the NIF and Z to measure oxygen opacity near CZB conditions. We present the current state of the data reduction and analysis for the NIF oxygen opacity campaign, and discuss future steps to ensure the resulting measurements are both accurate and precise.