Measurement of pressure-gradient-driven currents in tokamak edge plasmas.
Localized currents driven by pressure gradients play a pivotal role in the magnetohydrodynamic stability of toroidal plasma confinement devices. We have measured the currents generated in the edge of L- (low) and H- (high confinement) mode discharges on the DIII-D tokamak, utilizing the Zeeman effect in an injected lithium beam to obtain high resolution profiles of the poloidal magnetic field. We find current densities in excess of 1 MA/m2 in a 1 to 2 cm region near the peak of the edge pressure gradient. These values are sufficient to challenge edge stability theories based on specific current formation models.
Thomas
D M
DM
General Atomics, PO Box 85608, San Diego, California 92186-5608, USA.
Leonard
A W
AW
Lao
L L
LL
Osborne
T H
TH
Mueller
H W
HW
Finkenthal
D F
DF