title: Nature of transport across sheared zonal flows in electrostatic ion-temperature-gradient gyrokinetic plasma turbulence.
abstract: It is shown that the usual picture for the suppression of turbulent transport across a stable sheared flow based on a reduction of diffusive transport coefficients is, by itself, incomplete. By means of toroidal gyrokinetic simulations of electrostatic, collisionless ion-temperature-gradient turbulence, it is found that the nature of the transport is altered fundamentally, changing from diffusive to anticorrelated and subdiffusive. Additionally, whenever the flows are self-consistently driven by turbulence, the transport gains an additional non-Gaussian character. These results suggest that a description of transport across sheared flows using effective diffusivities is oversimplified.
authors.affiliation: Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071, USA. sanchezferlr@ornl.gov
authors.forename: R
authors.initials: R
authors.lastname: Sánchez
authors.forename: D E
authors.initials: DE
authors.lastname: Newman
authors.forename: J-N
authors.initials: JN
authors.lastname: Leboeuf
authors.forename: V K
authors.initials: VK
authors.lastname: Decyk
authors.forename: B A
authors.initials: BA
authors.lastname: Carreras