Kiel 2004 – wissenschaftliches Programm

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P: Plasmaphysik

P 10: Postersitzung: Niedertemperaturplasmen Plasmatechnologie II, Staubige Plasmen II, Magnetischer Einschluss II

P 10.19: Poster

Dienstag, 9. März 2004, 17:45–19:30, Foyer

Electron cyclotron resonance heating in the WEGA stellarator — •Yurij Podoba, Kinga Horvath, Heinrich P. Laqua, Johann Lingertat, and Friedrich Wagner — Max-Planck-Institut fur Plasmaphysik, Euratom Association, TI Greifswald, Wendelsteinstr. 1, 17491 Greifswald, Germany

The plasma in the WEGA stellarator is created and heated by microwaves at 2.45 GHz and Pmax=6 kW.

Initially, the microwaves were launched through a cylindrical tube the from low field side of the torus, in O-mode. The resonant toroidal magnetic field was located near the centre of the vacuum chamber.

Using this heating scenario, hollow profiles of el. density and temperature were observed, and the maxima of density and temperature, as well as the cut-off layer were located outside the last closed flux surface. Only a small part of the heating power reached the centre region after OXB conversion.

For the OXB process to be effective the wave has to be launched at an oblique angle to the magnetic surface, it is 45 deg for 1st harm.

The OXB conversion efficiency was further improved by cutting the antenna tube under an angle of 45 deg which increased the power launched at optimum oblique angle. With this antenna we obtained flat or peaked density profiles.

In this paper the latest results of antenna shape optimisation will be presented.