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P: Plasmaphysik

P 19: Magnetischer Einschluß 2

P 19.4: Talk

Monday, March 7, 2005, 15:30–15:45, HU 3038

Impurity up gradient transport in plasma edge turbulence — •Volker Naulin — Optics and Plasma Research, Association EURATOM-Risø National Laboratory, Roskilde, Denmark

Impurities in magnetically confined fusion plasmas poses severe restrictions on the performance of fusion devices. With the source for impurities localized in the plasma boundary region, accumulation and peaking of the impurity density and the related up-gradient transport – or pinching – is important in understanding and controlling impurity behaviour. While neoclassical effects can lead to some pinching of impurities, the rapid inward flow of impurities through the turbulent edge region of fusion devices is poorly understood. We here present an analytical prediction linking impurity pinch with the anomalous turbulent diffusion. Using 3D numerical simulations of electromagnetic drift-Alfven edge turbulence and describing the impurities as passive scalar, we verify the analytical predictions, with numerical values on the pinch velocity close to experiment. The influence of finite mass effects is additionally discussed.