Ion Viscous Heating in a Magnetohydrodynamically UnstablePinch at OverKelvin
- 23 February 2006
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 96 (7), 075003
- https://doi.org/10.1103/physrevlett.96.075003
Abstract
Pulsed power driven metallic wire-array pinches are the most powerful and efficient laboratory x-ray sources. Furthermore, under certain conditions the soft x-ray energy radiated in a 5 ns pulse at stagnation can exceed the estimated kinetic energy of the radial implosion phase by a factor of 3 to 4. A theoretical model is developed here to explain this, allowing the rapid conversion of magnetic energy to a very high ion temperature plasma through the generation of fine scale, fast-growing interchange MHD instabilities at stagnation. These saturate nonlinearly and provide associated ion viscous heating. Next the ion energy is transferred by equipartition to the electrons and thus to soft x-ray radiation. Recent time-resolved iron spectra at Sandia confirm an ion temperature of over 200 keV ( degrees), as predicted by theory. These are believed to be record temperatures for a magnetically confined plasma.
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