XGC Gyrokinetic simulations of coupled core delta-f and edge total-f models with a canonical maxwellian in the core*

One of the goals of the Exascale High-Fidelity Whole Device Modeling (ECP-WDM) project is to model the whole device of Tokamaks with core-edge coupled gyrokinetic simulations. This coupling of core delta-f and edge total-f gyrokinetic models [1] could enable a significant simulation speed-up. In particular, coupling core delta-f with edge total-f simulations, which raises many issues including the coupling of different gyrokinetic model equations together [2]. Therefore, we made the choice of solving the same equations but using different background f0 in the core and the edge. The goal being to avoid the background neoclassical drive in the core, as it drives large amplitude (GAM-like) perturbation. Our background Maxwellian is thus a linear combination of a canonical (f_cm) in the core with a local (f_lm) Maxwellian in the edge, f = wf_cm + (1 − w)f_lm. Preliminary electrostatic and electromagnetic simulations using this new core-edge model will be presented.

1. J. Dominski, et al. Phys. of Plasmas 28, 022301 (2021)

2. P. Trivedi, et al. Phys. of Plasmas 29, 032301 (2022)