Pseudo-Spectral Large-Eddy Simulation of Hall MHD Turbulence on GPU-based systems with a Minimal-Intrusion Porting Strategy

Abstract

A pseudo-spectral large-eddy simulation (LES) code for Hall magnetohydrodynamic (MHD) turbulence is optimized by overlapping communication and computation in three-dimensional fast Fourier transforms, reducing communication overhead. The CPU-based code is ported to GPU-based systems using a minimal-intrusion approach with OpenACC, cuFFT, and limited NCCL routines, enabling rapid migration with a unified code base. LES employing a recently developed sub-grid-scale (SGS) model successfully reproduces characteristic Hall MHD turbulence features. Energy spectra of forced homogeneous and isotropic turbulence are consistent with a high-resolution reference computation and with previously reported Hall MHD turbulence spectra. Sheet-like structures of the current density and enstrophy density in our LES are also consistent with those reported in our previous Hall MHD turbulence simulations. These results confirm the applicability of the SGS model and the fidelity of the GPU implementation.