Latitude dependence of convection and magnetic field generation in the cube

TL;DR

This paper investigates how convection intensity and magnetic field generation vary with latitude in a 3D thermal convection model within a cube, revealing increased kinetic energy towards the equator and implications for planetary magnetic fields.

Contribution

It introduces a model analyzing latitude dependence of convection and dynamo efficiency, explaining magnetic field configurations in planets and stars.

Findings

Kinetic energy increases from poles to equator by over an order of magnitude.

Magnetic energy also increases, but dynamo efficiency decreases towards the equator.

The model predicts strong azimuthal thermal winds influenced by thermal fluctuations.

Abstract

The 3D thermal convection in the Boussinesq approximation with heating from below and dynamo in the cube are considered. We study dependence of the convection intensity and magnetic field generation on the latitude in $\beta$-plane approximation. It is shown that kinetic energy gradually increases from the poles to the equator more than order of magnitude. The model predicts the strong azimuthal thermal wind, which direction depends on the sign of the thermal convective fluctuations. The spatial scale of the arising flow is comparable to the scale of the physical domain. The magnetic energy increases as well, however dynamo efficiency, i.e., the ratio of the magnetic energy to the kinetic one decreases to the equator. This effect can explain predominance of the dipole configuration of the magnetic field observed in the planets and stars. The approach is useful for modeling of the magnetohydrodynamic turbulence in planetary cores and stellar convective zones.