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  • Methods for investigating the spatial structure of density fluctuations in the plasma edge in fusion experiments demonstrated on the ASDEX divertor tokamak


Energy confinement in a tokamak is impaired by loss of particles in a radial direction, known as anomalous transport, which is attributed to fluctuations in density and potential within the plasma edge layer. The aim of this project was to gain more detailed knowledge of these fluctuations by studying their poloidal structure. In ASDEX the H(alpha) diagnostic devices were expanded from 8 to 16 channels, and a Langmuir probe with 16 tips was installed. The measurements were analysed using cross-correlation functions as well as 1D and 2D Fourier transform. The diagnostic tools, measurement methods and analysis techniques presented proved particularly successful in determining the poloidal velocity of the fluctuations and the velocity of the poloidal rotation of the plasma. The analysis procedure developed can in future be systematically employed to investigate fluctuations of H(alpha) ion saturation current, floating potential and particle flux for varying plasma parameters.

Additional information

Authors: THELMER G, Max-Planck-Institut für Plasmaphysik, Garching bei München (DE)
Bibliographic Reference: Report: IPP III/169 DE (1990) 98 pp.
Availability: Available from Max-Planck-Institut für Plasmaphysik, 8046 Garching bei München (DE)
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