Bremen 2017 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 22: Theory and Modelling II

P 22.6: Poster

Mittwoch, 15. März 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.