Simulation of plasma turbulence in stellarator equilibria with the global gyrokinetic particle-in-cell code XGC

We describe the ongoing effort to extend the stellarator capabilities of the global 5D total-f electromagnetic gyrokinetic particle-in-cell (PIC) code XGC (X-point Gyrokinetic Code). XGC is used to study multi-physics kinetic turbulence and transport phenomena in magnetic fusion plasmas [1, 2]. The code utilizes an unstructured triangular mesh in the radial-poloidal plane and is optimized for complex global geometry. It has mainly been used for simulations of tokamak plasmas, but XGC is also capable of studying turbulence in stellarator equilibria [3]. Simulations in 3D geometry have so far been limited to delta-f calculations of ion-scale electrostatic turbulence in the core plasma region. Under the SciDAC-5 project StellFoundry, an effort to extend the stellarator capabilities of XGC has been started. The new capabilities will include neoclassical physics, kinetic electron physics and the total-f model with Monte Carlo neutral particle physics. We also discuss how the stellarator simulations are being optimized for modern exascale architectures. Our longer-term goal is to enable XGC edge simulations of various stellarator divertor concepts.

References

[1] xgc.pppl.gov

[2] R. Hager, et al., 2022 Phys. Plasmas 29 112308

[3] M. D. J. Cole, et al., 2019 Phys. Plasmas 26 082501