Berlin 2001 – wissenschaftliches Programm
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P: Plasmaphysik
P 8: Magnetic Confinement and Plasma Technology (Poster Session)
P 8.3: Poster
Montag, 2. April 2001, 12:30–15:00, AT2
Fast swept probe measurements at W7AS — •Martin Schubert — Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr.2, D-85748 Garching
The aim of fast swept Langmuir probe measurements at W7AS is to measure poloidal electrostatic fluctuations, which may contribute significantly to the anomalous radial energy transport at the boundary of fusion plasmas. Probe bias voltage sweep allows one to make time-resolved measurements of the electron temperature, which is particularly useful for determination of the correct plasma potential from floating potential. The voltage sweep, however, must be faster than the bandwidth of the fluctuations of several 100 kHz. This paper reports the current status (setup, electronics, DAQ system) of fast swept probe measurements in the stellarator Wendelstein-7AS. Probe array measurements at the high and the low field side close ( < 1cm ) to the separatrix are also presented. Probe voltage and current signals have been recorded for different plasma confinement conditions. The obtained probe characteristics provide the parameters Vfloat, Te and Isat, in principle, but challenges in data handling (∼ 100 MB per shot ), separation of single characteristics and fitting have to be coped with.