abstract_prl2003
Turbulent transport reduction
and randomization of coherent fluctuations by zonal flows in toroidal plasma.
Abstract
Fluctuation-driven particle flux is greatly reduced in the plasma radial
region where zonal flows are present in the H-1 toroidal heliac. This occurs
without reduction in the fluctuation level. Statistical properties of fluctuations
are significantly modified in this region. It is shown that the randomization
of phases of coherent structures by zonal flows is responsible for the observed
effect. This mechanism of transport reduction complements theoretically predicted
random shearing of turbulence by zonal flows and does not require the fluctuations
suppression.
