Multi-fidelity simulations of turbulence in the plasma edge and scrape-off layer
Philipp Ulbl
Max Planck Institute for Plasma Physics
Tokamak Theory
The development of fusion energy relies heavily on understanding turbulence in the edge and scrape-off layer (SOL) of magnetic confinement fusion devices. Turbulent transport plays a key role in determining confinement, performance, and heat exhaust to the device wall. Despite significant advances in understanding core turbulence over the past few decades, the plasma edge remains a challenging region to model, owing to the intricate interplay of complex physics as well as geometrical complexities arising from the transition between closed and open magnetic field lines. This presentation introduces a novel multi-fidelity framework for simulating plasma turbulence in fusion devices with complex magnetic geometry, enabling simulations from the plasma edge to the SOL and up to the wall.
By leveraging two complementary codes, GENE-X, a high-fidelity collisional gyrokinetic turbulence code, and GRILLIX, a lower-fidelity drift-reduced fluid code, we demonstrate the benefits of combined studies using multiple fidelity methods. Recently, we implemented a Hermite-Laguerre spectral velocity space approach in GENE-X, which provides a lower-cost and reduced-fidelity alternative while maintaining high physics accuracy. This talk will discuss the latest developments in edge and SOL turbulence simulations, including numerical methods, computational aspects, and physics results. We will compare the performance and computational costs of different fidelity methods, highlighting the advantages of our multi-fidelity approach. Finally, we will discuss the potential of combining edge and SOL simulations with traditional gyrokinetic flux tube simulations to advance our understanding of edge plasma turbulence.