# Passive and active electromagnetic stabilization of free-surface liquid metal flows

## TL;DR

This paper demonstrates that electromagnetic fields can effectively stabilize free-surface liquid metal flows, achieving flatter layers through passive and active methods, which is crucial for applications like nuclear fusion reactors.

## Contribution

It provides experimental evidence of electromagnetic stabilization of liquid metal flows, introducing both passive and active techniques for achieving uniform free-surface layers.

## Key findings

- Magnetic fields flatten Galinstan layers passively.
- Electrical currents combined with magnetic fields further stabilize flows.
- Effective viscosity and gravity explain stabilization mechanisms.

## Abstract

Free-surface liquid metal flows tend to be uneven due to instabilities and other effects. Some applications, however, require constant, uniform liquid metal thickness. This is for example the case of liquid walls in nuclear fusion reactors. With this motivation, here we present experimental results on the stabilization of a free-surface flow of Galinstan. The flow was sustained by an electromagnetic induction pump featuring rotating permanent magnets. Evidence is reported of the flowing Galinstan layer becoming flatter in the presence of a sufficiently strong magnetic field, either alone (passive stabilization) or in combination with an electrical current passing through the liquid metal (active stabilization). The results are interpreted in terms of an effective viscosity and effective gravity, respectively.