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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:51 |
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Conference: Bucharest University Faculty of Physics 2021 Meeting
Section: Theoretical Physics and Applied Mathematics
Title:
Effects of intermittency on turbulent transport in tokamak plasmas
Authors:
L. POMARJANSCHI (1), D. I. PALADE (2), M. VLAD (2)
Affiliation:
1) Faculty of Physics, University of Bucharest, Romania
2) National Institute for Laser, Plasma & Radiation Physics, Romania
E-mail
ligiapomarjanschi@gmail.com
Keywords:
tokamak, turbulence, intermittency, transport
Abstract:
Turbulence plays a major role in the dynamics and confinement of tokamak plasmas. The turbulent electric field E is able, mainly via the ExB drift, to transport plasma across magnetic surfaces toward the walls. In the Scrape-off Layer region, in contrast to the core of the plasma, the turbulence is also characterized by intermittent phenomena: blobs, Alfven modes, or ELMs. In this work we investigate how the turbulent transport is affected by these intermittent features. We compute semi-analytical estimations of the transport coefficients which are confirmed with the use of two different statistical approaches: the Decorrelation Trajectory Method (DTM) and the direct numerical simulation method (DNS). We have found that the intermittent phenomena, which depart the turbulent field from Gaussianity, tend to inhibit the transport with a linear dependence on the excess kurtosis of the potential. The characteristic susceptibility is strongly dependent on the correlation time τ_c with a peak value close to the time-of-flight τ_fl.
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