Plasma and Fusion Research
Volume 5, 019 (2010)
Rapid Communications
- Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
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.
Keywords
phase space entropy, global relaxation, turbulent spreading, gyrokinetic simulation
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This paper may be cited as follows:
Kenji IMADERA, Yasuaki KISHIMOTO and Jiquan LI, Plasma Fusion Res. 5, 019 (2010).