Numerics and computation in gyrokinetic simulations of electromagnetic turbulence with global particle-in-cell codes

TL;DR

This paper explores the numerical challenges and computational costs of simulating electromagnetic turbulence in fusion plasmas using global gyrokinetic particle-in-cell codes, aiming to improve realism for future reactor designs.

Contribution

It advances gyrokinetic simulations by increasing plasma beta, machine size, and ion-electron mass ratio, and by incorporating realistic geometries with GPU-accelerated computing.

Findings

Numerical requirements for high-beta, large-scale simulations are identified.

GPU deployment significantly reduces computational costs.

Simulations include realistic tokamak and stellarator geometries.

Abstract

Electromagnetic turbulence is addressed in tokamak and stellarator plasmas with the global gyrokinetic particle-in-cell codes ORB5 [E. Lanti et al, Comp. Phys. Comm, vol. 251, 107072 (2020)] and EUTERPE [V. Kornilov et al, Phys. Plasmas, vol. 11, 3196 (2004)]. The large-aspect-ratio tokamak, down-scaled ITER, and Wendelstein 7-X geometries are considered. The main goal is to increase the plasma beta, the machine size, the ion-to-electron mass ratio, as well as to include realistic-geometry features in such simulations. The associated numerical requirements and the computational cost for the cases on computer systems with massive GPU deployments are investigated. These are necessary steps to enable electromagnetic turbulence simulations in future reactor plasmas.