title: Observation of coherent sheared turbulence flows in the DIII-D Tokamak.
abstract: Time-resolved measurements of the turbulent density flow field in a tokamak plasma reveal low-frequency ( approximately 15 KHz), coherent oscillations in the poloidal flow, v(theta). These flow oscillations have a long poloidal wavelength (m<3) and narrow radial extent (k(r)rho(i) approximately 0.2). The estimated flow-shearing rate is of the same order of magnitude as the turbulence decorrelation rate and may thus regulate the turbulence amplitude. These features are consistent with theoretically predicted axisymmetric, self-regulating, sheared flows recognized as geodesic acoustic modes.
authors.affiliation: University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706-1687, USA.
authors.forename: M
authors.initials: M
authors.lastname: Jakubowski
authors.forename: R J
authors.initials: RJ
authors.lastname: Fonck
authors.forename: G R
authors.initials: GR
authors.lastname: McKee