Nature of Transport across Sheared Zonal Flows in Electrostatic Ion-Temperature-Gradient Gyrokinetic Plasma Turbulence

4 pages, 4 figures.-- PACS nrs.: 52.35.Ra, 05.40.Fb, 52.55.Fa, 52.65.Tt.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.Research carried out at ORNL, managed by UT-Battelle LLC, for US DOE under Contract No. DE-AC05-00OR22725. Research funded by DOE Office of Science Grants No. DE-FG02-04ER54741 at University of Alaska and No. DE-FG02-04ER54740 at UCLA.Publicad