Mechanisms for magnetic Field generation in precessing cubes

TL;DR

This paper investigates how precessing cube flows can generate magnetic fields, highlighting the role of axisymmetric velocity components and the influence of parameters like Ekman number and turbulence.

Contribution

It reveals that flows in precessing cubes can produce magnetic fields through axisymmetric components, with effects depending on parameters like Ekman number and turbulence.

Findings

Large axisymmetric velocity components can generate magnetic fields.

Magnetic field generation diminishes at low Ekman numbers.

Critical magnetic Reynolds number increases with turbulence.

Abstract

It is shown that flows in precessing cubes develop at certain parameters large axisymmetric components in the velocity field which are large enough to either generate magnetic fields by themselves, or to contribute to the dynamo effect if inertial modes are already excited and acting as a dynamo. This effect disappears at small Ekman numbers. The critical magnetic Reynolds number also increases at low Ekman numbers because of turbulence and small scale structures.