Erlangen 2018 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 12: Magnetic Confinement - Poster
P 12.1: Poster
Dienstag, 6. März 2018, 16:15–18:15, Redoutensaal
The effect of plasma density fluctuations on the propagation of microwave beams used for plasma heating — •Alf Köhn1,2, Lorenzo Guidi2,3, Eberhard Holzhauer1, Omar Maj2, Emanuele Poli2, Antti Snicker2,4, Matthew Thomas5, and Roddy Vann5 — 1IGVP, Universität Stuttgart, Germany — 2Max-Planck-Institut für Plasmaphysik, Garching, Germany — 3Technische Universität München, Numerical Methods for Plasma Physics (M16), Garching, Germany — 4Department of Applied Physics, Aalto University, Finnland — 5York Plasma Institute, University of York, UK
Microwaves play an indispensable role in plasma experiments for heating and diagnostic purposes. When injected into the plasma or emitted by it the microwaves have to pass the plasma boundary, a region where strong plasma density fluctuations with fluctuation levels up to 100 % can occur. The interaction with the fluctuations can deteriorate the quality of the microwave beam resulting in reduced heating efficiencies or ambiguous diagnostics results. This is in particular a problem for the control of MHD instabilities by localized current drive using microwaves in the electron cyclotron range of frequencies. Here we present numerical simulations of the microwave interacting with the fluctuation layer by means of two different numerical codes, a full-wave code and a wave kinetic equation solver which treats the effects of fluctuations based in the Born approximation. Limitations of the latter treatment are explored and extrapolations towards ITER are drawn.