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Measurements of Diamagnetic Cavity Formation and Collapse using Proton Radiography in HED Plasmas

ORAL

Abstract

The interaction of laser-produced high-energy-density (HED) plasma with a magnetic field plays a key role in magnetized fusion schemes and laboratory astrophysics experiments such as magnetic reconnection and magnetized collisionless shocks.

Here we present recent experiments focused on the study of cross-field transport in magnetized HED plasmas at the OMEGA laser facility using an in-situ proton radiography platform, which allows precise measurements of non-uniform magnetic fields in plasma [1]. The plasma was generated by expanding a laser-produced plasma into a background magnetic field powered by MIFEDS, while the corresponding local electron temperature and density of the plasma were measured with 2ω Thomson scattering. The measured 2D magnetic field topology showed the clear formation of a diamagnetic cavity, its expansion in time, and subsequent collapse. The results are compared to magnetic field dynamics in GORGON 3D MHD simulations with initial non-uniform magnetic fields.

[1] C. Johnson et al, paper in preparation to RSI (2021)

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Publication: 1) "Proton deflectometry with in situ x-ray reference for absolute measurement of electromagnetic fields in high-energy-density plasma", C. Johnson, S.Malko, W. Fox et al. paper in submission to RSI (2021)<br>2) "Experimental study of diamagnetic cavity evolution in magnetized HED plasmas", S. Malko, D. Shaeffer, W. Fox, et al. in preparation to Physical Review Letters (2021).

Presenters

  • Sophia Malko

    PPPL, CLPU, Princeton Plasma Physics Laboratory

Authors

  • Sophia Malko

    PPPL, CLPU, Princeton Plasma Physics Laboratory

  • Derek B Schaeffer

    Princeton University, University of California, Los Angeles, Princeton University, USA

  • William R Fox

    Princeton Plasma Physics Laboratory, Princeton Plasma Physics Laboratory (PPPL), USA, Princeton University

  • Courtney L Johnson

    Rowan University

  • Gennady Fiksel

    University of Michigan

  • Amitava Bhattacharjee

    Princeton University

  • Anatoly Spitkovsky

    Princeton University

  • Patrick F Knapp

    Sandia National Laboratories

  • Andrea Ciardi

    Sorbonne University, LERMA, OBSPM

  • Jonathan R Davies

    University of Rochester, Laboratory for Laser Energetics, U. of Rochester, Laboratory for Laser Energetics, University of Rochester