Azimuthal Current Density Distribution Resulting from a Power Feed Vacuum Gap in Metallic Liner Experiments at 1 MA

ORAL

Abstract

We present a study investigating the initiation of plasma in solid, metallic liners where the liner thickness is large compared to the collisionless skin depth. A vacuum gap is introduced in the power feed and we investigate the effect of this on the azimuthal initiation of plasma in the liner. We present optical emission data from aluminum liners on the 1 MA, 100ns COBRA generator. We use radial and axial gated imaging and streak photography, which show a dependence of onset of emission with the size of a small power-feed vacuum gap. The evolution of ``hot-spots'' generated from breakdown vacuum gap evolves relatively slowly and azimuthal uniformity is not observed on the experimental time-scale. We also show measurements of the B-field both outside and inside the liner, using miniature Bdot probes, which show a dependence on the liner diameter and thickness, and a correlation to the details of the breakdown. These data will be compared to magneto-hydrodynamic simulations to infer how such non-uniformities may affect full liner implosion experiments.

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Authors

  • Simon Bott-Suzuki

    University of California - San Diego, La Jolla, CA, USA

  • S.W. Cordaro

    University of California - San Diego, La Jolla, CA, USA

  • Luis Sebastian Caballero Bendixsen

    University of California - San Diego, La Jolla, CA, USA, Center for Energy Research, UC San Diego, University of California San Diego

  • Levon Atoyan

    Cornell University, Ithaca, NY 14850, USA, Cornell University

  • T. Byvank

    Cornell University, Cornell University, Ithaca, NY 14850, USA

  • W. Potter

    Cornell University, Ithaca, NY 14850, USA

  • Bruce Kusse

    Cornell University, Ithaca, NY 14850, USA, Cornell University

  • J.B. Greenly

    Cornell University, Ithaca, NY 14850, USA

  • David Hammer

    Cornell University, Ithaca, NY 14850, USA, Cornell University

  • Jeremy Chittenden

    Imperial College London, Imperial College London, London, UK

  • C.A. Jennings

    Sandia National Laboratories, Sandia National Laboratories, Albuquerque, NM, USA