A proposal to measure iron opacity at conditions close to the solar convective zone-radiative zone boundary

Journal article

A major problem in stellar modelling is the discrepancy between solar models and helioseismology data in the position of the convective zone-radiative zone boundary in the sun. This could be explained by a large uncertainty in the calculated opacity data and recent experimental data on iron using the Sandia National Laboratory Z facility have shown large differences, up to a factor of 4, between measurement and prediction at plasma conditions close to the convective zone-radiative zone boundary. This paper describes a proposal for a radiative burn-through experiment to be fielded on NIF to observe if a radiation wave transit through a Fe2O3 sample is consistent with the factor of 2–4 change in the iron opacity seen in the Z experiments. A target design and the diagnostic method are described. A detailed radiation-hydrodynamic model has been used to generate synthetic results and explore the sensitivities and experimental accuracy needed for the proposed measurement.

Authors: Hoarty, D; Morton, J; Jeffery, M; Pattison, L; Wardlow, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: High Energy Density Physics
• Volume: 32
• Issue: July 2019
• Pages: 70-76
• Publication date: 2019-05-14
• Acceptance date: 2019-05-14
• DOI: 10.1016/j.hedp.2019.05.003
• ISSN: 1574-1818
• Language: English
• Keywords: FFR; Radiative transport; Plasma radiative opacity; Stellar modelling