Diagnosing Pulsed Power Produced Plasmas with X-ray Thomson Scattering at the Nevada Terawatt Facility

ORAL

Abstract

We present experimental results on X-ray Thomson scattering (XRTS) at the Nevada Terawatt Facility (NTF) to study current driven plasmas. Using the Leopard laser, $\sim$ 30 J and pulse width of 0.8 ns, we generated He-$\alpha $ emission (4.75 keV) from a thin Ti foil. Initial parameter scans showed that the optimum intensity is $\sim$ 10$^{15} $W/cm$^{2}$ with a foil thickness of 2 $\mu $m for forward X-ray production. Bandwidth measurements of the source, using a HAPG crystal in the Von Hamos configuration, were found to be $\Delta $E/E $\approx $ 0.01. Giving the scattering angle of our experimental setup of 129 degrees and X-ray probing energy, the non-collective regime was accessed. The ZEBRA load was a 3 mm wide, 500 $\mu $m thick, and 10 mm long graphite foil, placed at one of the six current return posts. Estimates of the plasma temperature, density and ionization state were made by fitting the scattering spectra with dynamic structure factor calculations based on the random phase approximation for the treatment of charged particle coupling.

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Authors

  • Julio Valenzuela

    University of California, San Diego, Center for Energy Research, Univ of California, San Diego

  • C. Krauland

    University of California, San Diego

  • D. Mariscal

    University of California, San Diego

  • Igor Krasheninnikov

    University of California, San Diego, University of California at San Diego, Center for Energy Research

  • Farhat Beg

    University of California, San Diego, University of California San Diego, Center for Energy Research, Univ of California, San Diego, University of California at San Diego, Center for Energy Research

  • P. Wiewior

    Univ of Nevada, Reno, University of Nevada, Reno

  • Aaron Covington

    University of Nevada, Reno, Nevada Terawatt Facility, UNR, Univ of Nevada, Reno, University of Nevada at Reno, University of Nevada, Reno-Physics Department/Nevada Terawatt Facility

  • Radu Presura

    Voss Scientific, LLC, Voss Scientific, Llc, Voss Scientific

  • T. Ma

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab, LLNL

  • C. Niemann

    University of California, Los Angeles

  • P. Mabey

    University of Oxford

  • G. Gregori

    University of Oxford