Plasma phenomena in super slow motion
Dr. Michael Griener has been leading the new junior research group for experimental validation of physics-based plasma boundary models at IPP since 2025. Here he explains his research.
Why is the plasma edge so crucial for fusion research?
Dr. Griener: The plasma edge is the region in the reactor that isolates the hot fusion plasma, which is many millions of degrees Celsius hot, from the reactor wall – this is where the stability of the reactor and the load on the wall are determined. Turbulent structures such as filaments or instabilities in the plasma edge modes can lead to very high heat loads there in the short term. Without a precise understanding of these processes, we will not be able to build a robust, economical fusion power plant.
What is the goal of your new junior research group?
Dr. Griener: We want to experimentally verify physics-based models of the plasma boundary – that is, we compare simulations with real measurement data. To do this as accurately as possible, we connect physical diagnostics such as the thermal helium beam, probe measurements, reflectometry or neutral gas pressure measurements via ‘synthetic diagnoses’ with simulation results. With these synthetic diagnoses, we digitally reconstruct the signals recorded by a real measuring device in the experiment. This is the only way to compare reality and theory. We therefore check whether our models really reflect what happens in the experiment. Only when this has been verified does it make sense to scale the simulations to power plant size.
What motivates you personally about this research?
Dr. Griener: I deliberately chose fusion research at the IPP because I can be part of a very large team here. In other physics disciplines, you usually work in small local working groups. At the IPP, I find world-class experts in every area of fusion whom I can approach personally.
What fascinates me about my field of research is how the stability of an entire fusion plant can be determined in a tiny space and in microseconds. With our methods, we can zoom in on these processes as if with a super microscope and then observe them in super slow motion. We are learning to understand these processes in a plasma and even control them in a targeted manner. This helps us to develop safe and stable operating scenarios for future fusion power plants.
Michael Griener received his doctorate in 2018 from the IPP and the Technical University of Munich (TUM). Dr. Griener then became a PostDoc at the IPP. He lectures at the TUM. Dr. Griener’s new junior research group at the Max Planck Institute for Plasma Physics (IPP) is funded by the German Federal Ministry of Research, Technology and Space (BMFTR).
The interview with Dr. Michael Griener is the first in the series “Three junior research groups—three questions,” which introduces the new IPP junior research groups funded by the German Federal Ministry of Education and Research.
More information about Michael Grieners junior research group can be found here: https://www.ipp.mpg.de/5544559/plasmarandmodelle