Augsburg 2006 – wissenschaftliches Programm

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P: Plasmaphysik

P 24: Plasma-Wand Wechselwirkung 3

P 24.2: Vortrag

Mittwoch, 29. März 2006, 15:00–15:15, 1002

Spectroscopic Diagnostic of Tungsten in Fusion Plasmas — •T. Pütterich¹, R. Neu¹, R. Dux¹, M. O Mullane², A. Whiteford², A. Kallenbach¹, J.C. Fuchs¹, H. Meister¹, I. Radivojevic¹, and ASDEX Upgrade Team¹ — ¹MPI für Plasmaphysik, EURATOM-Association, Garching, GERMANY — ²Department of Physics, University of Strathclyde, Glasgow, UK

Tungsten (W) is a candidate material for the first wall of a fusion reactor due to its robustness against plasma erosion. In ASDEX Upgrade (AUG) 85% of the first wall are coated with W. The W-impurity content of the plasma is diagnosed by spectroscopy in the VUV and soft X-ray spectral range. The analysis of the spectra relies on the availability of atomic data for W. Baseline data for nearly all W ions were calculated by the Cowan-code, including the electronic structure and excitation rates. Within the framework of the ADAS project these data are processed by a collisional-radiative model. The resulting, synthetic spectra were compared to experimental spectra from AUG in the electron temperature (T_e) range of 1 – 5 keV. Closely connected are the investigations on the fractional abundances of ionization states. The abundances of Ag-like W²⁷⁺ to Co-like W⁴⁷⁺ were measured versus T_e and compared to several theoretical data sets describing ionization and recombination. In future tokamaks, like ITER, temperatures far above 5 keV will be important for diagnosing W. The respective spectra of Ni-like W⁴⁶⁺ to Be-like W⁷⁰⁺ were calculated based on the new data sets. Furthermore, the data enabled the calculation of the total power radiated by W, which determines the maximum tolerable amount of W in a reactor plasma.