Bayreuth 1998 – scientific programme

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P: Plasmaphysik

P 14: Magnetischer Einschluß III

P 14.1: Fachvortrag

Wednesday, March 11, 1998, 14:00–14:30, H 14

Anomalous Particle Pinch and Other Effects of Warm Ions
on Drift Alfvén Turbulence — •B. Scott — Max-Planck Institut für Plasmaphysik, EURATOM-IPP Ass., Boltzmannstr. 2, 85748 Garching

Computations of fluid drift Alfvén turbulence in three-dimensional tokamak geometry are performed taking into account the gradients and self-consistent fluctuations of the density and both temperatures, in addition to the currents and E × B flows. Transport is maximised when the gradients work together, with equal scale lengths. With the density gradient at zero, the average particle flux is inward, and the energy transport is greatly weakened. The transport is strongly dependent on the ion/electron temperature ratio, due to the presence of both the nonlinear electron drift wave instability and the ion temperature gradient (ITG) mode. The scaling with the plasma beta is as in the cold-ion case, indicating that electron dynamics is still important even when the ITG mode gives the strongest drive. Results of a search for bifurcation mechanisms will be reported, as well as the progress in building a fully nonlocal version of the model capable of studying large perturbations such as those involved in the Edge Localised Mode (ELM) events observed in tokamak H-mode discharges