Publication: Nature of Transport across Sheared Zonal Flows in Electrostatic Ion-Temperature-Gradient Gyrokinetic Plasma Turbulence
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2008-11-14
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The American Physical Society
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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.
Description
4 pages, 4 figures.-- PACS nrs.: 52.35.Ra, 05.40.Fb, 52.55.Fa, 52.65.Tt.
Keywords
[PACS] Plasma turbulence, [PACS] Random walks and Levy flights, [PACS] Tokamaks, spherical tokamaks, [PACS] Gyrofluid and gyrokinetic simulations
Bibliographic citation
Phys. Rev. Lett. 101, 205002 (2008)