Workshop on Astrophysical Opacities

Update on the iron opacity experiments on the NIF

2 Aug 2017, 11:40

40m

Western Michigan University Kalamazoo, MI, USA

Invited talks Atomic Opacities

Speaker

Dr Ted Perry (Los Alamos National Laboratory)

Description

Recent iron opacity experiments on the Sandia National Laboratories Z machine have shown up to factors of two discrepancies between theory and experiment. Much effort has been put into looking at the experiment and the opacity theories but a resolution of the discrepancies has not been forthcoming. It is emphasized that the discrepancies present a fundamental theoretical challenge. To help resolve this question an experimental platform for doing opacity experiments is being developed on the National Ignition Facility (NIF). This platform will be able to replicate the experimental conditions of the Z experiments and also extend the measurements to other temperatures and densities. Experiments to date have demonstrated the capability to produce a satisfactory X-ray backlighting source and the ability to achieve the appropriate plasma conditions in the opacity sample. Some initial iron data has been taken but there are still problems with backgrounds and with the spectrometer used to make the measurements. The path forward for reducing the backgrounds and improving the spectrometer will be presented. It is expected that data for comparing with the Z experiments will be available within a year.