Aachen PK 2003 – wissenschaftliches Programm
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P: Plasmaphysik
P 17: Poster III
P 17.15: Poster
Donnerstag, 20. März 2003, 17:30–19:15, Foyer
Edge ion temperature profile measurements with Li beam CXRS on ASDEX Upgrade — •Matthias Reich1, Elisabeth Wolfrum1, Josef Schweinzer1, Hartmut Ehmler2, Hans-Ulrich Fahrbach1, Josef Neuhauser1, and ASDEX Upgrade Team1 — 1Max Planck Institut für Plasmaphysik, Boltzmannstr. 2, D-8 5748 Garching — 2Max Planck Institut für Plasmaphysik, Wendelsteinstraße 1, D-17491 Greifswald
The global performance of magnetically confined fusion plasmas turns out to be strongly dependent on the plasma edge behaviour. Understanding the underlying physics mechanisms there requires detailed knowledge of the plasma parameters. While electron density and temperature profiles at the edge are routinely measured in ASDEX Upgrade with high accuracy, this is not yet the case for ion temperatures. The method of choice - charge exchange recombination spectroscopy on carbon using a narrow, chopped Li-beam (I=1..3 mA, E=30...75 keV) as the electron donor - is limited by strong background photon noise and perturbations by edge plasma fluctuations. However, for selected discharges time averaged ion temperature profiles with a radial resolution of about 5 mm can be obtained. Preliminary results for the especially important low to medium density discharges (ECRH and NB heated), where ion and electron temperatures tend to decouple, as well as recent improvements of the system are presented and discussed. The ion temperature profiles obtained from the Li beam CXRS diagnostic are compared to those from a low energy neutral CX analyser diagnostic (LENA) and potential benefits of combining both diagnostics are shown.