Implicit-Explicit time integration scheme with Physics-based preconditioning for two-fluid tokamak boundary simulations
Abstract
In this work, a globally stiffly accurate Implicit-Explicit (IMEX) Runge-Kutta scheme is developed and implemented in the GBS code [Ricci et al., Plasma Phys. Control. Fusion, 2012], for two-fluid plasma turbulence simulations. The stiffest phenomena, governed by shear Alfvén waves and parallel diffusion, are treated implicitly, while the remaining non-stiff terms are advanced explicitly. This splitting enables time steps well beyond the Courant-Friedrichs-Lewy limit, without incurring the full computational cost of a globally implicit formulation. To efficiently solve the implicit subsystem at each time step, a three-dimensional physics-based preconditioner, inspired by techniques developed in the magnetohydrodynamic (MHD) context, is used. The resulting framework is verified through the method of manufactured solutions and exhibits both algorithmic and parallel scalability. Significant advantages in numerical stability and computational efficiency are demonstrated with respect to an adaptive explicit Runge-Kutta scheme.
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BibTeX
@misc{bassanini2026implicitexplicit,
title = {{Implicit-Explicit time integration scheme with Physics-based preconditioning for two-fluid tokamak boundary simulations}},
author = {Micol Bassanini and Simone Deparis and Paolo Ricci and Brenno De Lucca and Davide Mancini and Louis Stenger and Sergio García Herreros},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.33677},
eprint = {2609.33677},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.33677},
}
RIS
TY - UNPB
TI - Implicit-Explicit time integration scheme with Physics-based preconditioning for two-fluid tokamak boundary simulations
AU - Micol Bassanini
AU - Simone Deparis
AU - Paolo Ricci
AU - Brenno De Lucca
AU - Davide Mancini
AU - Louis Stenger
AU - Sergio García Herreros
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.33677
UR - https://arxiv.org/abs/2609.33677
AB - In this work, a globally stiffly accurate Implicit-Explicit (IMEX) Runge-Kutta scheme is developed and implemented in the GBS code [Ricci et al., Plasma Phys. Control. Fusion, 2012], for two-fluid plasma turbulence simulations. The stiffest phenomena, governed by shear Alfvén waves and parallel diffusion, are treated implicitly, while the remaining non-stiff terms are advanced explicitly. This splitting enables time steps well beyond the Courant-Friedrichs-Lewy limit, without incurring the full computational cost of a globally implicit formulation. To efficiently solve the implicit subsystem at each time step, a three-dimensional physics-based preconditioner, inspired by techniques developed in the magnetohydrodynamic (MHD) context, is used. The resulting framework is verified through the method of manufactured solutions and exhibits both algorithmic and parallel scalability. Significant advantages in numerical stability and computational efficiency are demonstrated with respect to an adaptive explicit Runge-Kutta scheme.
ER -