Induction in a von Karman flow driven by ferromagnetic impellers

TL;DR

This paper investigates how the magnetic properties of ferromagnetic impellers influence magnetic induction in a von Karman flow of gallium, with implications for understanding the VKS dynamo.

Contribution

It demonstrates that differences in electrical conductivity and magnetic permeability between impellers and fluid induce specific magnetic effects in magnetohydrodynamic flows.

Findings

Induction effects depend on impeller material properties.

Magnetic Reynolds numbers of order unity are achieved.

Implications for the VKS dynamo are discussed.

Abstract

We study magnetohydrodynamics in a von K\'arm\'an flow driven by the rotation of impellers made of material with varying electrical conductivity and magnetic permeability. Gallium is the working fluid and magnetic Reynolds numbers of order unity are achieved. We find that specific induction effects arise when the impeller's electric and magnetic characteristics differ from that of the fluid. Implications in regards to the VKS dynamo are discussed.