Plasma and Fusion Research
Online ISSN : 1880-6821
ISSN-L : 1880-6821
Rapid Communications
Global Profile Relaxation and Entropy Dynamics in Turbulent Transport
Kenji IMADERAYasuaki KISHIMOTOJiquan LI
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2010 Volume 5 Pages 019

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Abstract

A hierarchical entropy balance equation retaining the dynamics in the radial direction is introduced to study non-local turbulent transport and the associated global profile relaxation. It consists of first- and second-order equations that describe the entropy dynamics related to thermodynamics/fluid quantity and the corresponding micro-scale phase space fluctuations, respectively. Specifically, the second-order equation describes not only a local entropy production related to heat and density flux (i.e., zonal flow), but also the spatial convection of perturbed entropy. We investigated the entropy dynamics in ion-temperature-gradient driven turbulence based on a global gyrokinetic Vlasov simulation in slab geometry. Entropy convection plays an important role in the relaxation dynamics dominated by the avalanche process. A self-organized relaxed state is established, in which short-wavelength temperature corrugation, i.e., zonal pressure, is regulated by zonal flow shear.

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© 2010 by The Japan Society of Plasma Science and Nuclear Fusion Research
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