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P: Fachverband Plasmaphysik

P IV: Poster: Niedertemperaturplasmen II, Astrophysikalische Plasmen, Magnetischer Einschluss, Plasma-Wand-Wechselwirkung

P IV.2: Poster

Thursday, March 13, 2008, 16:00–18:30, Poster C2

Rotation in the Presence of Turbulence in Large Tokamaks — •Bruce Scott — Max-Planck-Institut für Plasmaphysik, EURATOM Association, Garching

Turbulence in the tokamak core is studied using three dimensional computations within the low frequency electromagnetic gyrofluid model. The entire background, including the confining magnetic field, is carried self consistently. The axisymmetric component describing the neoclassical equilibrium for flows and currents is perturbed by the turbulence, which is resolved down to the ion gyroradius. The degree to which the total ion flow divergence departs from zero indicates the relative strength of perturbation by the turbulence. For small tokamaks the E× B eddy Reynolds stress due to the turbulence strongly perturbs the flows and therefore the radial electric field (E_r) profile. The large tokamak regime, entered when the minor radius is about 200 ion gyroradii, is characterised by a tightly clamped flow equilibrium with negligible effect from the turbulence on the E_r profile. Various scenarios with different profile combinations (density, temperature, toroidal momentum) are considered. This study suggests it is very unlikely that turbulence Reynolds stress can play a role in core confinement transitions ("internal transport barriers").