Spectrally Accelerated Edge and Scrape-Off Layer Gyrokinetic Turbulence Simulations

Fuente: arXiv
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Auteurs principaux: Frei, B. J., Ulbl, P., Trilaksono, J., Jenko, F.
Format: Preprint
Publié: 2024
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author Frei, B. J.
Ulbl, P.
Trilaksono, J.
Jenko, F.
author_facet Frei, B. J.
Ulbl, P.
Trilaksono, J.
Jenko, F.
contents This paper presents the first gyrokinetic (GK) simulations of edge and scrape-off layer (SOL) turbulence accelerated by a velocity-space spectral approach in the full-f GK code GENE-X. Building upon the original grid velocity-space discretization, we derive and implement a new spectral formulation and verify the numerical implementation using the method of manufactured solution. We conduct a series of spectral turbulence simulations focusing on the TCV-X21 reference case [Oliveira D. S. et al., Nucl. Fusion 62, 096001 (2022)] and compare these results with previously validated grid simulations [Ulbl P. et al., Phys. Plasmas 30, 107986 (2023)]. The spectral approach reproduces the outboard midplane (OMP) profiles (density, temperature, and radial electric field), dominated by trapped electron mode (TEM) turbulence, with excellent agreement and significantly lower velocity-space resolution. Thus, the spectral approach reduces the computational cost by at least an order of magnitude, achieving a speed-up of approximately 50 for the TCV-X21 case. This enables high-fidelity GK simulations to be performed within a few days on modern CPU-based supercomputers for medium-sized devices and establishes GENE-X as a powerful tool for studying edge and SOL turbulence, moving towards reactor-relevant devices like ITER.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09232
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spectrally Accelerated Edge and Scrape-Off Layer Gyrokinetic Turbulence Simulations
Frei, B. J.
Ulbl, P.
Trilaksono, J.
Jenko, F.
Plasma Physics
This paper presents the first gyrokinetic (GK) simulations of edge and scrape-off layer (SOL) turbulence accelerated by a velocity-space spectral approach in the full-f GK code GENE-X. Building upon the original grid velocity-space discretization, we derive and implement a new spectral formulation and verify the numerical implementation using the method of manufactured solution. We conduct a series of spectral turbulence simulations focusing on the TCV-X21 reference case [Oliveira D. S. et al., Nucl. Fusion 62, 096001 (2022)] and compare these results with previously validated grid simulations [Ulbl P. et al., Phys. Plasmas 30, 107986 (2023)]. The spectral approach reproduces the outboard midplane (OMP) profiles (density, temperature, and radial electric field), dominated by trapped electron mode (TEM) turbulence, with excellent agreement and significantly lower velocity-space resolution. Thus, the spectral approach reduces the computational cost by at least an order of magnitude, achieving a speed-up of approximately 50 for the TCV-X21 case. This enables high-fidelity GK simulations to be performed within a few days on modern CPU-based supercomputers for medium-sized devices and establishes GENE-X as a powerful tool for studying edge and SOL turbulence, moving towards reactor-relevant devices like ITER.
title Spectrally Accelerated Edge and Scrape-Off Layer Gyrokinetic Turbulence Simulations
topic Plasma Physics
url https://arxiv.org/abs/2411.09232