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P: Fachverband Plasmaphysik

P 13: Magnetischer Einschluss I

P 13.4: Talk

Wednesday, April 1, 2009, 14:15–14:30, INP-Staffelgeschoß

Radiation Effects During Disruptions in ASDEX Upgrade — •Bernhard Reiter, Gabriella Pautasso, Thomas Eich, Albrecht Herrmann, Marc Maraschek, Asher Flaws, Tilman Lunt, Pascal de Marne, and the ASDEX Upgrade Team — Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association IPP, D-85748 Garching, Germany

The heat load to plasma facing components caused by disruptions is a serious challenge for next step devices like ITER. In ASDEX Upgrade, the commissioning of a broad-band radiation diagnostic (XVR), which samples AXUV diode signals with microsecond time resolution, was finished in 2008. The lines of sight arrangement allows for 2-D radiation pattern reconstruction, which provides insight into radiation features of the different disruption phases. Analysis of disruption mitigation experiments show the puffed neon and helium surrounding the core in the form of radiating layers during the thermal quench phase. Radiation from the center appears later on in the disruption, during quenching of the plasma current. These radiation features are additionally investigated by utilising a fast imaging camera, which is equipped with band-pass filters for visible emission lines of injected species.
Studies of toroidal asymmetry of radiation power and poloidal localisation of radiative load to plasma facing components in various kinds of disruptions are carried out with XVR. In order to evaluate the amount of power deposition by conduction, the radiated fraction is deducted from the total power flux, which is measured by thermography cameras.