Full-f electromagnetic gyrokinetic turbulence simulations of the edge and scrape-off layer of ASDEX Upgrade with GENE-X

Abstract

Understanding and predicting turbulence in the edge and scrape-off layer (SOL) is critical for the optimization of magnetic confinement fusion devices. While there has been progress along these lines, especially with the help of fluid codes, the development of full- f electromagnetic gyrokinetic codes for the edge and SOL, in general, diverted geometries, remains crucial. In this work, we present simulations of the edge and SOL of the ASDEX Upgrade tokamak with the novel grid-based gyrokinetic (continuum) code GENE-X. The presented simulations are performed at both reduced and realistic electron-to-ion mass ratios on millisecond time scales, studying profile evolution. We compare the resulting plasma profiles to experimental measurements and to previous simulations with the Braginskii fluid code GRILLIX. Furthermore, we measure and validate the SOL power falloff length λq according to the Eich fit function. Based on the results, we discuss the influence of the ion-to-electron mass ratio and collisional effects on gyrokinetic SOL turbulence.