  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.
