Bulletin of the American Physical Society
54th Annual Meeting of the APS Division of Plasma Physics
Volume 57, Number 12
Monday–Friday, October 29–November 2 2012; Providence, Rhode Island
Session QI3: Z-pinch, HED Magnetic Fields
3:00 PM–5:00 PM,
Wednesday, October 31, 2012
Room: Ballroom BC
Chair: Mingsheng Wei, General Atomics
Abstract ID: BAPS.2012.DPP.QI3.2
Abstract: QI3.00002 : Experiments and simulations studying electrothermal instabilities in magnetically accelerated implosion systems*
3:30 PM–4:00 PM
Preview Abstract Abstract
(Sandia National Laboratories)
Electrothermal instabilities in electrical conductors can occur whenever the electrical conductivity depends on temperature. Of particular interest are electrothermal instabilities that occur when the electrical conductivity decreases with temperature, which is the case in most metals until they are heated into a Spitzer-like conductivity regime. These instabilities form stratified structures perpendicular to the current flow that are similar in appearance to m=0 sausage type instabilities and can geometrically couple to magneto-Rayleigh-Taylor (MRT) instabilities as the system is accelerated. Several experiments were performed using the 100-ns Z accelerator that drove up to 20 MA through well-characterized, initially solid and smooth ($<$50 nm RMS) Al and Cu rods. The experiments used 2-frame (6151 eV) or 2-color (1865/6151 eV) monochromatic x-ray backlighting to image instability growth on the surface of the rods. Excellent agreement is obtained between measurements and simulations that show the majority of the instability growth occurs immediately after the surface of the rod melts and is in regions that are stable to MRT instabilities and unstable to electrothermal instabilities. We will also show how MRT instability theory alone cannot explain the levels of instability growth observed in experiments.
*Sandia is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL8500.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.DPP.QI3.2
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