Detection of zero-mean-frequency zonal flows in the core of a high-temperature tokamak plasma.
A low-frequency, spectrally broad (Deltaf approximately 10 kHz) poloidal flow structure that peaks near zero frequency is observed in time-resolved measurements of the turbulence velocity field in the core region (r/a approximately 0.6-0.9) of DIII-D tokamak plasmas. These flows exhibit a long poloidal wavelength (low m) and a short radial coherence length comparable to the ambient turbulence decorrelation length. Characteristics of these observed poloidal flows are consistent with the theoretically predicted residual or zero-mean-frequency zonal flows.
Gupta
D K
DK
University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706, USA.
Fonck
R J
RJ
McKee
G R
GR
Schlossberg
D J
DJ
Shafer
M W
MW