title: Detection of zero-mean-frequency zonal flows in the core of a high-temperature tokamak plasma.
abstract: 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.
authors.affiliation: University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Gupta
authors.forename: R J
authors.initials: RJ
authors.lastname: Fonck
authors.forename: G R
authors.initials: GR
authors.lastname: McKee
authors.forename: D J
authors.initials: DJ
authors.lastname: Schlossberg
authors.forename: M W
authors.initials: MW
authors.lastname: Shafer