Berlin 2014 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 2: Magnetic Confinement I
P 2.5: Vortrag
Montag, 17. März 2014, 12:05–12:20, SPA HS202
Influence of density fluctuations on microwave propagation and mode conversion — •Alf Köhn1, Eberhard Holzhauer1, Jarrod Leddy3, Martin O'Brien2, Mirko Ramisch1, Roddy Vann3, and Thomas Williams3 — 1Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Universität Stuttgart — 2EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, UK — 3York Plasma Institute, Department of Physics, York, U.K.
Electron Bernstein waves (EBWs) provide a method to heat over-dense plasmas, which are otherwise inaccessible for electromagnetic waves. EBWs are very well absorbed at the electron cyclotron resonance and their harmonics in high- and low-temperature plasmas. They are of electrostatic nature and need to be coupled to electromagnetic waves injected from the outside. This coupling process usually takes place at the plasma boundary, where large density variations can occur. These variations can significantly distort the microwaves traversing this region. To investigate this interaction, simulations with the full-wave code IPF-FDMC have been performed. In a first step, the influence of a single blob will be discussed. To this end, a Gaussian shaped density perturbation is added to a homogeneous background and the spatial distribution of the electric field of the microwave after the interaction is analyzed. The model is then extended to broadband density fluctuations. Both, the deterioration of the coupling process of the EBW and the general distortion of a traversing microwave beam is investigated.