title: Long-range correlations induced by the self-regulation of zonal flows and drift-wave turbulence.
abstract: By means of a unique probe array, the interaction between zonal flows and broad-band drift-wave turbulence has been investigated experimentally in a magnetized toroidal plasma. Homogeneous potential fluctuations on a magnetic flux surface, previously reported as long range correlations, could be traced back to a predator-prey-like interaction between the turbulence and the zonal flow. At higher frequency the nonlocal transfer of energy to the zonal flow is dominant and the low-frequency oscillations are shown to result from the reduced turbulence activity due to this energy loss. This self-regulation process turns out to be enhanced with increased background shear flows.
authors.affiliation: Center for Energy Research, University of California at San Diego, San Diego, California 92093, USA.
authors.forename: P
authors.initials: P
authors.lastname: Manz
authors.forename: M
authors.initials: M
authors.lastname: Ramisch
authors.forename: U
authors.initials: U
authors.lastname: Stroth