Physical Review Letters -- April 10, 1995
Volume 74, Issue 15, pp. 2945-2948

Conservation of magnetic helicity during plasma relaxation

H. Ji, S. C. Prager, and J. S. Sarff

Department of Physics, University of Wisconsin, Madison, Wisconsin 53706

The change in magnetic energy and magnetic helicity has been measured during the sawtooth relaxation in the Madison Symmetric Torus reversed-field pinch. The larger decay of the energy (4.0%-10.5%), relative to helicity decay (1.3%-5.1%), modestly supports the helicity conservation hypothesis in Taylor's relaxation theory. However, the observed helicity change is larger than the simple magnetohydrodynamics prediction. Enhanced fluctuation-induced helicity transport during the relaxation is observed.

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