Berlin 2014 – scientific programme
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P: Fachverband Plasmaphysik
P 17: Poster Session - Helmholtz Graduate School for Plasma Physics
P 17.10: Poster
Wednesday, March 19, 2014, 16:30–18:30, SPA Foyer
Poloidal asymmetries of heavy impurities in the ASDEX Upgrade plasma — •Tomas Odstrcil1, Thomas Puetterich1, Anja Gude1, Ralph Dux1, Didier Mazon2, and ASDEX Upgrade Team1 — 1Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching, Germany — 2CEA, IRFM F-13108 Saint Paullez-Durance, France
For heavy and highly charged impurities multiple mechanisms exist that produce non-constant impurities densities on the flux surfaces. As for neoclassical and turbulent transport models such an asymmetrie is highly importance an effort is launched to experimentally characterize the asymmetries comparing them with theoretical expectations.
In the ASDEX Upgrade tokamak (AUG) is routinely observed increase of outboard tungsten density in fast rotating plasma. This asymmetry is caused by the centrifugal force pushing tungsten ions outward due to its high mass. Furthermore, the high charge makes heavy impurities sensitive to poloidal variations of the plasma potential. The variation can be generated by magnetic trapped ions heated by RF heating. In such a case, the presence of an inboard asymmetry or at least the absence of an outboard asymmetry due to the centrifugal force can be observed. Finally, ion-impurity friction enhanced by the large charge of the impurity ions may cause a relatively weak up-down asymmetry of the impurity density.
The aim of this poster is to show first evidence of these asymmetries in the AUG plasmas, the description of the used methodology, and to compare with theoretical models based on the parallel force balance.