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Updated: Sep 13, 2026

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster
Published on: December 22, 2018
First Observation of Currents Induced by Alfvén Eigenmodes in a Magnetic Confinement Device
W W Heidbrink1, X D Du2, M E Austin3
1University of California, Irvine, California 92697, USA.
Abstract:
Instabilities driven by energetic particles normally reduce fusion power, but recent studies find Alfvén eigenmode instabilities can drive "zonal" flows and currents that reduce thermal transport, improving overall performance. Motional Stark effect data from the DIII-D tokamak reveal changes in magnetic pitch angle during the phase when Alfvén-eigenmode nonlinearity drives zonal flows, suppresses microturbulence, and increases the electron and ion temperatures. Measured changes in the safety factor of Δq/q[over ¯]≃5% occur in roughly 20 ms, consistent with a rough estimate based on the measured zonal flow.
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