Augsburg 2006 – scientific programme
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P: Plasmaphysik
P 4: Diagnostik 1; Niedertemperaturplasmen / Plasmatechnologie 2; Magnetischer Einschluß 2
P 4.5: Poster
Monday, March 27, 2006, 17:00–19:00, Flure
A Heavy Ion Beam Probing System for the WEGA Stellarator — •Martin Schubert1 and Alexander Zhezhera2 — 1Max-Planck-Institut fuer Plasmaphysik, Greifswald, Germany — 2Kharkov Institute of Plasma Physics, Kharkov, Ukraine
In combination with the future WEGA ECRH operation (28 GHz, 20 kW, 0.5 T) a Heavy Ion Beam Probe (HIBP) system is being installed. The principle of this measurement is the perpendicular injection of a primary beam, consisting of singly charged ions, and the detection of a secondary beam, which consists of double or higher charged ions. Ion gyration radii in both the primary and the secondary beam are large compared to the plasma size. Beam geometry and detector aperture determine the spatial resolution, i.e. the size of the primary beam ionisation volume inside the plasma. Analysing the ion energy in the secondary beam yields the electrostatic plasma potential. Taking into account the ionisation cross section and the beam attenuation, the electron density can be calculated. Radial profiles are obtained using electrostatic deflection of the primary beam. For the WEGA stellarator in Greifswald, a system has been designed in collaboration with the Kharkov Institute for Plasma Physics/Ukraine. Presently the system is being assembled. At WEGA, 50 keV Na+ ions will be injected into H, He and Ar plasma. The spatial resolution is estimated to 1 cm. Plasma potential and density measurements will be cross-checked with Langmuir probe data.