Göttingen 2025 – scientific programme

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P: Fachverband Plasmaphysik

P 10: Poster Session I

P 10.38: Poster

Tuesday, April 1, 2025, 16:15–18:15, ZHG Foyer 1. OG

Influence of ELMs on O-X mode conversion efficiency — •Shibangi Majumder, Christos Vagkidis, and Alf Köhn-Seemann — IGVP, University of Stuttgart, Germany

Edge Localized Modes (ELMs) constitute a continuous relaxation of the edge plasma pressure gradient. The respective perturbation of the electron plasma density profile can perturb microwaves injected into the plasma for heating purposes. This is particularly true for mode coupling processes like the O-SX-B mode conversion, where an injected O-mode couples to an SX-mode near the cut-off layer. The SX-mode is then reflected and propagates to the upper-hybrid resonance, where it can couple to electron Bernstein waves, which are electrostatic waves that are very well absorbed at the electron cyclotron resonance. The efficiency of the O-SX coupling depends strongly on the injection angle with respect to the background magnetic field. In this work, we explore the effect of ELMs on the O-SX coupling with an FDTD code, providing thus insights into the interplay between ELM-induced edge conditions and microwave heating performance. This further can contribute to a deeper understanding of plasma heating and confinement mechanisms in fusion experiments.

Keywords: microwave; mode coupling; simulation; fdtd; edge localized modes