Bochum 2002 – wissenschaftliches Programm
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P: Plasmaphysik
P 22: Poster: Magnetische Fusion, Plasmadiagnostik, Dichte Plasmen
P 22.15: Poster
Dienstag, 19. März 2002, 17:40–18:40, HZO Foyer
Comparison of Electron Temperatures Measurements Applying Langmuir Probes and Passive Spectroscopy — •D. Schröder, W. Bohmeyer, U. Wenzel, and B. Koch — Max-Planck-Insititut für Plasmaphysik, Bereich Plasmadiagnostik, Mohrenstrasse 41, 10117 Berlin, Germany, EUROATOM Ass.
In the last years low temperature divertor operation has become accessible in fusion experiments. To understand and model the various processes occurring in such plasmas reliable measurements of the electron temperature Te and the electron density ne are crucial.
It was found, however, in several tokamaks and stellerators, that the electron temperatures determined by means of Langmuir probes differ substantially from those measured spectroscopically (intensity of Balmerlines, continuum) as soon as Te drops below ∼ 10 eV. Such low temperatures are of particular interest for future fusion reactors, because of the high recombination rates that enable a considerable reduction of the energy deposit on the divertor tiles. Thus, three body recombination peaks around ∼ 1 eV; similarly, molecular activated recombination is important for Te≤ 3 eV.
To understand the discrepancies found in these Te values, systematic measurements were performed with Langmuir probes and spectroscopy at the PSI-2 plasma generator.