Impurity-induced suppression of core turbulence and transport in the DIII-D tokamak
Turbulence is significantly reduced in a tokamak plasma as a result of neon seeding of an L-mode discharge. Correspondingly, confinement is improved and cross-field ion thermal transport reduced. Fully saturated turbulence in the range 0.1</=k( perpendicular)rho(s)</=0. 6 is measured at rho = 0.7 and exhibits a factor of 5 reduction in total power after neon injection, with almost complete suppression for k( perpendicular)rho(s)>0.35. These observations are consistent with a reduction in the calculated linear growth rate for k( perpendicular)rho(s)>0.5 and an increase in the measured ExB flow shearing rate.
McKee
G
University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Burrell
K
Fonck
R
Jackson
G
Murakami
M
Staebler
G
Thomas
D
West
P