Magnetic reversals in a simple model of MHD

TL;DR

This paper investigates magnetic field reversals in a shell model of magnetohydrodynamics, revealing how turbulence influences magnetic dynamics in low Prandtl number fluids.

Contribution

It introduces a coupled shell model for MHD turbulence with dynamo constraints, highlighting magnetic reversals linked to hydrodynamic turbulence.

Findings

Magnetic reversals occur spontaneously in the model.

Magnetic field evolution is connected to turbulence properties.

Reversal dynamics depend on turbulence characteristics.

Abstract

We study a simple magnetohydrodynamical approach in which hydrodynamics and MHD turbulence are coupled in a shell model, with given dynamo constrains in the large scales. We consider the case of a low Prandtl number fluid for which the inertial range of the velocity field is much wider than that of the magnetic field. Random reversals of the magnetic field are observed and it shown that the magnetic field has a non trivial evolution linked to the nature of the hydrodynamics turbulence.