Parts | Days | Selection | Search | Downloads | Help
P: Plasmaphysik
P 4: Diagnostics II
P 4.1: Talk
Tuesday, April 3, 2001, 16:30–16:45, 2032
Measurement of the C6+-Density in the Edge-Plasma-Region of the W7-AS Stellarator — •Hartmut Ehmler, Kent McCormick, and W7-AS Team — Max-Planck-Institut für Plasmaphysik
Since summer of 2000, W7-AS is operating with an island-divertor. One of the major goals of the divertor is to control particle and power exhaust in such a way that sputtering of the graphit targets is minimized, since a high amount of carbon in the plasma leads to significant radiation losses.
At W7-AS the amount of C6+-impurities in the edge plasma is measured by means of the Lithium-beam-diagnostic using the light emitted by charge-exchange with fast injected Li-atoms. The concentration of C6+ is determined at 14 radial positions simultaneously by a new photomultiplier-based system. The results show that the C6+-density increases linearly during a variation of the central electron density from 2× 1019 up to 7× 1019 m−3. As a second parameter the influence of the magnetic configuration is studied.