Exploring extreme magnetization phenomena in directly-driven imploding cylindrical targets

POSTER

Abstract

This poster shows extended-magnetohydrodynamics (MHD) simulations exploring an extreme magnetized plasma regime realisable by cylindrical implosions on the OMEGA laser facility. This regime is characterized by highly compressed magnetic fields (greater than 10~kT across the fuel), which contain a significant proportion of the implosion energy and induce large electrical currents in the plasma. Parameters governing the different magnetization processes such as Ohmic dissipation and suppression of instabilities by magnetic tension are presented, allowing for optimization of experiments to study specific phenomena. For instance, a dopant added to the target gas-fill can enhance magnetic flux compression while enabling spectroscopic diagnosis of the imploding core. In particular, the use of Ar K-shell spectroscopy is investigated by performing detailed non-LTE atomic kinetics and radiative transfer calculations on the MHD data. Direct measurement of the core electron density and temperature would be possible, allowing for both the impact of magnetization on the final temperature and thermal pressure to be obtained. By assuming the magnetic field is frozen into the plasma motion, which is shown to be a good approximation for highly magnetized implosions, spectroscopic diagnosis could be used to estimate which magnetization processes are ruling the implosion dynamics; for example, a relation is given for inferring whether thermally-driven or current-driven transport is dominating.

*This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This document was prepared as an account of work sponsored by an agency of the United States government.

Publication: Walsh et al., Plasma Physics and Controlled Fusion (submitted)

Presenters

  • Chris A Walsh

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Lab

Authors

  • Chris A Walsh

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Lab

  • Ricardo Florido

    • University of Las Palmas de Gran Canaria
    • Universidad de Las Palmas de Gran Canaria

  • Mathieu Bailly-Grandvaux

    • UCSD
    • University of California, San Diego
    • University of California San Diego
    • Center for Energy Research,University of California, San Diego, USA.

  • Francisco Suzuki-Vidal

    • Imperial College London

  • Jeremy P Chittenden

    • Imperial College London

  • Aidan C Crilly

    • Imperial College London
    • CIFS, The Blackett Laboratory, Imperial College London

  • Marco A Gigosos

    • Universidad de Valladolid
    • University of Valladolid

  • Roberto C Mancini

    • University of Nevada, Reno

  • Gabriel Perez Callejo

    • Université de Bordeaux - CEA/CESTA
    • University of Bordeaux
    • CELIA - University of Bordeaux
    • CELIA

  • Christos Vlachos

    • University of Bordeaux

  • Christopher McGuffey

    • University of California, San Diego
    • Center for Energy Research,University of California, San Diego, USA.; General Atomics, San Diego, USA.

  • Farhat N Beg

    • University of California San Diego
    • University of California, San Diego
    • Center for Energy Research,University of California, San Diego, USA.

  • Joao J Santos

    • University of Bordeaux
    • CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), University of Bordeaux, Talence, France.