Aachen PK 2003 – scientific programme
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P: Plasmaphysik
P 4: Poster I
P 4.27: Poster
Monday, March 17, 2003, 17:45–19:15, Foyer
Langmuir Probe Measurements in the WEGA Stellarator — •Kinga Horvath, Michael Laux, and Johann Lingertat — Max-Planck-Institut für Plasmaphysik, Euratom Association, Wendelsteinstraße 1, 17491 Greifswald, Germany
Langmuir probe measurements have been performed in weakly magnetized (0.0875 T), low-pressure ( 0.5 · 10−3 Pa ≤ p ≤ 17.5 · 10−3 Pa ) helium and hydrogen plasmas of the WEGA stellarator. A simple, cylindrical, graphite probe as well as a double probe were used. The observed characteristics do not show saturation of the ion current. The reason for this anomaly could be the presence of a fast electron component in the plasma caused by the heating method ( ECRH at 2.45 GHz ). Using the model from [ 1 ] for derivation of the current to the probe for a two-temperature Maxwellian electron distribution the characteristics were successfully fitted. Radial profiles of the electron temperature, density and plasma potential as a function of heating power and neutral gas pressure have been obtained.
[ 1 ] P.C.Stangeby, Plasma Phys. Control. Fusion 37 (1995), 1031-1037