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P: Fachverband Plasmaphysik
P 11: Helmholtz Graduate School II
P 11.2: Vortrag
Dienstag, 14. März 2017, 14:25–14:50, HS 1010
Doppler reflectometry power response regimes: modelling and experiments — •J.R. Pinzon1,2, T. Happel1, P. Hennequin3, E. Blanco4, T. Estrada4, U. Stroth1,2, and The ASDEX Upgrade Team1 — 1Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching — 2Physik-Department E28, TUM, D-85748 Garching — 3Laboratoire de Physique des Plasmas, Ecole Polytechnique, France — 4Laboratorio Nacional de Fusion, CIEMAT, 28040 Madrid, Spain.
The experimental characterization of turbulence in fusion plasmas is relevant for confinement studies and the development of a fusion reactor. Doppler reflectometry (DR) is a microwave diagnostic technique used for the characterization of density turbulence in fusion plasmas. It can provide perpendicular wavenumber(k⊥)-spectra of the turbulence, velocity of the plasma and, using two reflectometer channels, the radial correlation length Lr of the turbulence. However it is well known, from theory and simulations, that a non-linear response of the diagnostic is involved, which makes data analysis and interpretation challenging.
The power response in Doppler reflectometry is studied using 2D full wave simulations and the physical optics model. Apart from the already known linear and saturation regimes, a new enhanced non-linear power response is observed. Results from the modelling are compared with experiments from the ASDEX Upgrade Tokamak. The impact of the previous regimes in k⊥-spectra and Lr measurements is studied.