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Title: Characterizing turbulent transport in ASDEX Upgrade L-mode plasmas via nonlinear gyrokinetic simulations

The nature and level of turbulent transport in the outer core of low-confinement (L-mode) discharges performed at the ASDEX Upgrade tokamak [Kallenbach et al., Nucl. Fusion 51, 094012 (2011)] are examined. Previously, it was found that for an L-mode discharge of the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)] gyrokinetic simulations were unable to reproduce the experimental ion heat flux, underestimating it by almost an order of magnitude. In the present work, employing the GENE gyrokinetic turbulence code, an extensive nonlinear study is performed for L-mode discharges of ASDEX Upgrade in order to cross-check this observation. It is shown that no systematic underprediction can be found in these simulations—instead, discrepancies with respect to experimental transport levels are small enough to be resolved within the uncertainties of the experimental profiles. Moreover, it is shown that some turbulence properties resemble closely those of the underlying linear microinstabilities at least out to 90% of the minor radius, so that quasilinear transport models remain, in principle, applicable even for these parameters, provided that appropriate nonlinear saturation rules can be developed.
Authors:
; ; ; ;  [1] ;
  1. Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22218340
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 12; Other Information: (c) 2013 Euratom; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASDEX TOKAMAK; CHARGED-PARTICLE TRANSPORT; COMPUTERIZED SIMULATION; DOUBLET-3 DEVICE; ELECTRIC DISCHARGES; G CODES; HEAT FLUX; IONS; L-MODE PLASMA CONFINEMENT; NONLINEAR PROBLEMS; PLASMA; PLASMA INSTABILITY; PLASMA SIMULATION; TRANSPORT THEORY; TURBULENCE