Hannover 2010 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 11: Invited Talks Windisch, Manz, Loffhagen, Hauser
P 11.1: Hauptvortrag
Mittwoch, 10. März 2010, 11:00–11:30, B 305
Intermittent plasma transport — •Thomas Windisch1, Olaf Grulke1,2, and Thomas Klinger1,2 — 1Max-Planck-Institute for Plasma Physics, EURATOM Association, 17491 Greifswald, Germany — 2Ernst-Moritz-Arndt University Greifswald, Germany
The edge turbulence in toroidal fusion devices is characterized by intermittent fluctuations of the density and potential, thereby strongly affecting the transport. This fluctuation-induced transport of plasma particles and energy across the confining magnetic field affects several key reactor issues, e.g., heat and particle fluxes to the first wall, recycling, impurities and Helium ash removal. Experimental results and numerical simulations show that the intermittent bursts in the scrape-off layer (SOL) can be ascribed to large-amplitude self-organized coherent structures, called ’blobs’, which propagate radially outwards through the SOL with a velocity of less than one tenth of the ion sound speed typically. A statistical analysis clearly revealed that radially propagating turbulent structures are also observed in the linearly magnetized laboratory experiment VINETA. Their formation is closely related to the primary drift-wave instability and their radial velocity is determined by the E×B-convection due to the self-consistent potential perturbation. In the talk special attention is paid to the evolution of the spatio-temporal dynamics of the turbulent structures across an externally imposed E×B-shear layer. An emissive filament is used to produce a local variation of the radial potential profile, which gives rise to an azimuthally sheared E×B-flow. The nonlinear response of the structure is studied using multi-probe arrays.