Domino model in geodynamo

TL;DR

This paper models the geodynamo using a Lagrangian formalism for magnetohydrodynamic cyclones, revealing how boundary heat flux variations influence magnetic field reversals, aligning with 3D dynamo simulation results.

Contribution

It introduces a Lagrangian formalism approach to model the geodynamo, demonstrating the impact of boundary heat flux variations on magnetic field reversals.

Findings

Heat flux variations modulate reversal frequency.

Two reversal scenarios observed: dipole-quadrupole transition and tilt reversal.

Model aligns with 3D dynamo simulation results.

Abstract

Using Lagrangian formalism we consider evolution of the ensemble of interacting magnetohydrodynamic cyclones governed with Langevin type equations in the rotating medium. This problem is relevant to the planetary cores where the Rossby numbers are small and geostrophic balance takes place. We show that variations of the heat flux at the outer boundary of the spherical shell modulates frequency of the reversals of the mean magnetic field that is in accordance with the 3D dynamo simulations. Two scenarios of reversals were bserved. Either the axial dipole decreases in favour of quadrupole and then grows in opposite direction or the mean dipole tilts and reverses without decrease of its amplitude.