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(TH/P2-14) Theoretical Analysis of Long Range Turbulent Transport in the Scrape-Off-Layer

Ph. Ghendrih1), Y. Sarazin1), G. Attuel1), S. Benkadda2), P. Beyer2), C. Clément1), G. Falchetto1), C. Figarella2), X. Garbet1), V. Grandgirard1), M. Ottaviani1)
1) Association Euratom-CEA, DRFC/DSM/CEA, CEA Cadarache, St Paul lez Durance, Cedex, France
2) UMR 6633 PIIM CNRS-Université de Provence, Marseille, France

Abstract.   Flux driven SOL turbulence and its impact on ELM relaxation, main chamber recycling and probe measurements are addressed in this paper. A significant fraction of the flux (44 %) is found to be due to rare events with long-range ballistic transport ($ \sim$ 0.10 m). The average density profile exhibits an exponential fall-off of ($ \sim$ 0.03 m). Simulations of a probe measurement of the ion saturation current show that measurements of the ion saturation current and its fluctuations can be distorted. The measurement of the ion saturation current is ``recovered'' when the probe tip is small (< 3 Larmor radii). Although the spectrum of the fluctuations is little affected, one finds that most of the large intermittent events are not measured. The probe underestimates the bursty feature of cross-field transport. In the simulations, control of turbulent cross-field transport has been achieved with wall biasing. Shearing of the avalanches is readily observed. This provides a means to reduce plasma-wall interaction in the main chamber.

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IAEA 2003