Greifswald Physics Colloquium: Dr. Alf Köhn-Seemann

Achieving controlled nuclear fusion requires both heating plasmas to extreme temperatures and understanding their behaviour in real time. Microwaves play a central role in both challenges. This talk explores the dual role of microwaves in fusion research. As for the heating, we examine how high-power microwave beams are coupled into the plasma enabling highly localized power deposition and what challenges are met in this process. As for the diagnostics, we show how microwaves enable non-perturbing measurements of equilibrium and dynamics quantities. Taken together, the heating and diagnostics capabilities illustrate why microwaves are not just a supporting technology but actually a cornerstone for fusion. The talk is designed to be accessible to ageneral physics audience and allows reflections on how a technology from everyday life find its extreme application in the pursuit of fusion energy.