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P: Plasmaphysik
P 21: Plasma-Wand Wechselwirkung 2
P 21.2: Vortrag
Mittwoch, 29. März 2006, 11:45–12:00, 1002
Influence of the magnetic topology on edge plasma parameters in the ergodic layer at TEXTOR-DED — •Derek Harting1, Detlev Reiter1, Yuehe Feng2, Oliver Schmitz1, and Heinke Frerichs1 — 1Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany — 2Max-Plank-Institut für Plasmaphysik, EURATOM Association, 17491 Greifswald, Germany
The Dynamic Ergodic Divertor (DED) induces a magnetic perturbation in the edge plasma of the TEXTOR Tokamak, which leads to an ergodisation of the field lines in this region. By this the connection length topology is modified such that a periodic poloidal structure of fluxtubes with short (1 poloidal turn) and long (up to 18 poloidal turns) connection length is formed. Numerical simulations with the EMC3-EIRENE code package for different discharge conditions have been carried out. The simulations show that (depending on the empirically choosen anomalous perpendicular transport coefficients D and χ) the fluxtubes with short (one poloidal turn) connection length carry a reduced plasma density and electron temperature. A first direct comparison of the available experimental data in the edge plasma region of TEXTOR (He-Beam, Li-Beam, Hα camera) with the simulations results confirme this drop of density and electron temperature inside the fluxtubes with short connection length. This is a first indication of the earlier proposed general feature of ergodic divertors to channel power and particles onto the target predominantly via fluxtubes selected also by their radial excursion, rather than by their connection length alone.