Observation of velocity-independent electron transport in the reversed field pinch.
Confinement of runaway electrons has been observed for the first time in a reversed field pinch during improved-confinement plasmas in the Madison Symmetric Torus. Energy-resolved hard-x-ray flux measurements have been used to determine the velocity dependence of the electron diffusion coefficient, utilizing computational solutions of the Fokker-Planck transport equation. With improved-confinement, the fast electron diffusivity drops by 2 orders of magnitude and is independent of velocity. This suggests a change in the transport mechanism away from stochastic magnetic field diffusion.
O'Connell
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Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA. roconnell@wisc.edu
Den Hartog
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Forest
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Anderson
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Biewer
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Chapman
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Craig
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Fiksel
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Prager
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Sarff
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Terry
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Harvey
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