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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.

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.