Sub-grid-scale model for studying Hall effects on macroscopic aspects of magnetohydrodynamic turbulence

TL;DR

This paper introduces a novel sub-grid-scale model for large eddy simulations of Hall magnetohydrodynamic turbulence, enabling efficient and accurate study of macroscopic effects influenced by the Hall term.

Contribution

A new sub-ion-scale sub-grid-scale model is developed to efficiently simulate Hall MHD turbulence, capturing macroscopic effects and reducing computational costs.

Findings

Successfully reproduces statistical properties of turbulence

Enables simulations with lower computational cost

Retains ion-electron separation effects in LES

Abstract

A new sub-grid-scale model is developed for studying influences of the Hall term on macroscopic aspects of magnetohydrodynamic turbulence. Although the Hall term makes numerical simulations extremely expensive by exciting high-wave-number coefficients and makes magnetohydrodynamic equations stiff, studying macroscopic aspects of magnetohydrodynamic turbulence together with the Hall term is meaningful since this term often influences not only sub-ion-scales but also macroscopic scales. A new sub-ion-scale sub-grid-scale model for large eddy simulations of Hall magnetohydrodynamic turbulence is developed in order to overcome the difficulties. Large eddy simulations by the use of the new model successfully reproduce statistical natures such as the energies and probability density functions of the vorticity and current density, keeping some natures intrinsic to Hall magnetohydrodynamic turbulence. Our new sub-grid-scale model enables numerical simulations of homogeneous and isotropic Hall magnetohydrodynamic turbulence with a small computational cost, improving the essential resolution of an LES from that carried out with earlier models, and retaining the ion-electron separation effects by the Hall term in the grid scales.