Towards global electrostatic ion-scale turbulence simulations in stellarators with XGC*

In this presentation, we detail progress towards simulations of electrostatic ion-scale turbulence in stellarator geometries with the whole volume, total-f, gyrokinetic particle-in-cell code XGC. In recent work, XGC has been adapted for stellarator/heliotron geometries. XGC has been successfully benchmarked against the kinetic codes EUTERPE and FORTEC-3D for energetic particle confinement and GAM physics in such devices. So far, no fully global electrostatic turbulence simulation has been performed for a stellarator with any gyrokinetic code. A goal of this project is to perform such simulations with the XGC code. The stellarator developments in XGC are first benchmarked with a standard circular tokamak linear ITG case. An unstructured field-aligned mesh is then constructed for Wendelstein 7-X geometry. Preliminary electrostatic results with XGC will be presented for linear ion-scale calculations in Wendelstein 7-X, global to the last closed flux surface.