Modeling of High-Energy-Density Plasmas Formed in Experiment with Megagauss Magnetic Fields
Author: Volodymyr Makhin
Requested Type: Poster Only
Submitted: 2006-12-19 12:55:28
Co-authors: M.A.Angelova, T.S.Awe, B.S.Bauer, S.Fuelling, I.R.Lindemuth, R.E.Siemon (U of Nevada, Reno); W.L.Atchison (LANL); S.F. Garanin (VNIIEF, Sarov, Russia)
Contact Info:
University of Nevada, Reno
5625 Fox Ave.
Reno, NV 89506
USA
Abstract Text:
The surface response to megagauss (MG) fields is important for eventual Magnetized Target Fusion experiments [1,2]. Recent radiation-hydro numerical simulations in a planar geometry by Garanin et al.[3] show how plasma can be generated through thermal processes on a metal surface. In a recent series of 24 shots on the Zebra experiment at the University of Nevada, Reno, metal plasma formation and stability were studied on the surface of typical liner materials in the MG regime. The surface response of aluminum hourglass cylindrical conductors was modeled numerically assuming experimentally relevant current rise-times, which determine the ratio of current skin depth relative to conductor radius. Important effects include plasma formation, radiation transport, and the unstable m=0 mode driven by curvature of the magnetic field that holds the surface plasma against the metal. MHRDR simulations [4] show luminosity, radial expansion, surface melting, vaporization, and plasma formation in reasonable agreement with experimental data. Interesting details such as a compression wave that propagates from the surface to the axis and back are more difficult to diagnose experimentally, but are possibly connected with the observation of surface expansion after the time of peak current. The sensitivity of results to various equation-of-state and resistivity models is also discussed.
1. R.E. Siemon, et al., Stability analysis and numerical simulation of a hard-core diffuse z pinch during compression with Atlas facility liner parameters, Nuclear Fusion 45, 1148 (2005).
2. S.F. Garanin, V.I.Mamyshev, and V.B. Yakubov, The MAGO system: current status, IEEE Trans. Plasma Sci. 34, 2273, (2006).
3. S.F. Garanin, G.G. Ivanova, D.V. Karmishin, and V.N. Sofronov, Diffusion of a megagauss field into a metal, J. Appl. Mech. Tech. Phys. 46, 153, (2005).
4. A. Esaulov, et al., Magnetohydrodynamic simulation of the inverse-pinch plasma discharge, Phys. Plasmas 11, 1589 (2004).
*Work was supported by DOE grants OFES DE-FG02-04ER54752 and DE-FG02-06ER54892.
Characterization: C
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