Extending the gyrokinetic code GENE-X to stellarators

Plasma turbulence is a fundamental process and a key transport mechanism in magnetic confinement fusion (MCF). Due to its complex, non-linear dynamics, turbulence is typically studied through numerical simulations. While turbulence in the confined core plasma has been extensively researched for decades, recent focus has shifted toward the plasma edge and scrape-off layer (SOL). This region, although more challenging to study, is critically important as it sets the boundary conditions for the core plasma and governs physical fluxes to plasma-facing components. This holds true for both major MCF concepts: tokamaks and stellarators. In this work, we introduce a first-of-its-kind tool capable of investigating non-local gyrokinetic turbulence in the edge and SOL of both tokamaks and stellarators. The gyrokinetic turbulence code GENE-X, initially developed for tokamak simulations, has been extended to accommodate stellarator geometries. Here, we detail the modifications made to the code, describe the verification of its new capabilities, and present its first application: the study of turbulence in a stellarator configuration featuring a non-segmented island divertor. This constitutes the world’s first simulation of Eulerian gyrokinetic turbulence in the edge and SOL of stellarators.