Extended X-ray Absorption Fine Structure (EXAFS) as a Probe of Temperature and Density in Fe Under Shock-Ramp Compression

ORAL

Abstract

Probing the behavior of iron under the extreme conditions of Earth's core requires innovative experimental techniques. At the Omega EP laser facility, we employed shock-ramp compression to access off-Hugoniot states of Fe at pressures exceeding 400 GPa. Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was used to extract local atomic structure and temperature information under these conditions. By combining EXAFS data with velocity interferometry (VISAR) measurements, we determined the pressure, density and thermal state of Fe near melting. Our results provide a constraint for the melting line at these extreme conditions. This study demonstrates the effectiveness of EXAFS as a diagnostic tool for investigating temperature under dynamic compression.

*This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC

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Presenters

  • Yuan Ping

    • Lawrence Livermore National Laboratory

Authors

  • Yuan Ping

    • Lawrence Livermore National Laboratory

  • Amy L Coleman

    • Lawrence Livermore National Laboratory

  • Stanimir A Bonev

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • Andrew Krygier

    • Lawrence Livermore National Laboratory

  • Hong Sio

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab

  • Federica Coppari

    • Lawrence Livermore National Laboratory

  • David A Chin

    • Laboratory for Laser Energetics
    • University of Rochester

  • Matthew Edward Signor

    • University of Rochester

  • J. Ryan R Rygg

    • Laboratory for Laser Energetics, University of Rochester

  • Gilbert W Collins

    • University of Rochester
    • Laboratory for Laser Energetics

  • Jon H Eggert

    • Lawrence Livermore National Laboratory