Bremen 2017 – scientific programme
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P: Fachverband Plasmaphysik
P 22: Theory and Modelling II
P 22.6: Poster
Wednesday, March 15, 2017, 16:30–18:30, HS Foyer
Microwave beam broadening due to plasma density fluctuations — •Alf Köhn1, Michael Brookman2, Lorenzo Guidi1, Eberhard Holzhauer3, Jarrod Leddy4, Omar Maj1, Emanuele Poli1, Antti Snicker1, Matthew Thomas4, and Roddy Vann4 — 1Max Planck Institute for Plasma Physics, Garching, Germany — 2Institute for Fusion Studies, Austin (TX), US — 3IGVP, Stuttgart, Germany — 4York Plasma Institute, York, UK
Electromagnetic waves in the microwave regime are commonly used for heating, current drive, and diagnostic purposes in fusion plasmas. They suffer, however, from the fact that they have to traverse the plasma boundary, a region where substantial density fluctuations can occur resulting in perturbations of the microwave beam. Time-averaging over the effect of the fluctuations basically leads to a broadening of the microwave beam. The strength of this broadening is investigated with full-wave simulations. The comparison with computational less time expensive methods serves to identify their region of validity. The turbulence parameters are varied in a series of parameter scans to find the cases with the strongest perturbations. Possible implications for localized heating and current drive in fusion plasmas are also discussed.