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

ORAL

Abstract

The location of the Sun’s convection zone boundary (CZB) is precisely inferred by helioseismic measurements, but solar models predict a significantly shallower depth1. One hypothesis is that opacity models underpredict the true radiative opacity of the solar mixture at CZB conditions. If true, this could also affect theoretical cooling rates for white dwarfs (WDs), which are used as chronometers for stellar populations like the disk of the Milky Way2. Oxygen contributes the largest fraction to the opacity near the Sun’s CZB and makes up approximately half the composition of an average WD. Measurements of oxygen opacity near solar CZB conditions are underway at the National Ignition Facility (NIF). Recent advancements in the analysis of these experiments and future oxygen opacity experiments on the NIF are presented.



[1] Basu & Antia, Phys. Rep. (2008)

[2] Saumon et al., Phys. Rep. (2022)

*This work was supported by the Wootton Center for Astrophysical Plasma Properties under NNSA Stewardship Science Academic Alliances award number DE-NA0004149. Experiment time was provided by the Discovery Science Program of LLNL. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.LLNL-ABS-2009349

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Publication: Mayes, D. C., Hobbs, B. A., Heeter, R. F. et al., HEDP (2025)
Hobbs, B. A., Mayes, D. C., Heeter, R. F. et al. Rev. Sci. Instrum. (2024)

Presenters

  • Bryce Hobbs

    • University of Texas at Austin

Authors

  • Bryce Hobbs

    • University of Texas at Austin

  • Daniel C Mayes

    • University of Texas at Austin

  • Robert F Heeter

    • Lawrence Livermore National Laboratory

  • Paul A Bradley

    • Los Alamos National Laboratory (LANL)

  • Christopher J Fontes

    • Los Alamos National Laboratory (LANL)

  • Matthias Hohenberger

    • Lawrence Livermore National Laboratory

  • Heather M Johns

    • Los Alamos National Laboratory (LANL)

  • Yekaterina P Opachich

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore National Lab

  • Harry Francis Robey

    • Los Alamos National Laboratory (LANL)

  • Stanislav Stoupin

    • Lawrence Livermore National Laboratory

  • Matthew S Wallace

    • Nevada National Security Sites

  • Michael Houston Montgomery

    • University of Texas at Austin

  • Theodore S Perry

    • Los Alamos National Laboratory (LANL)

  • Don E Winget

    • University of Texas at Austin
    • The University of Texas at Austin