Elongation of a ferrofluid droplet near a permanent magnet: a tidal or magnetic energy effect?

It is commonly known that Earth's ocean tides are related to the Moon's gravity. However, many people (including advanced physics students!) misunderstand the mechanism. Tidal effects are ubiquitous in astrophysics but are difficult to demonstrate because of their scale. A demonstration of tidal effects has been proposed utilizing droplets of ferrofluids (colloidal suspensions of ferromagnetic particles in a liquid) which stretch as they fall toward a permanent magnet. The magnetic attractive force due to the permanent magnet's nonuniform 1/r³ field is stronger on the near end of the droplet than the far end, which leads to tidal stretching similar to that of Earth's oceans in the 1/r² gravitational field of the Moon. However, free droplets of ferrofluid are known to elongate even in a uniform applied magnetic field because the elongated shape lowers the droplet's magnetic energy in its own field. Which effect dominates when we perform such an experiment? Is this truly a demonstration of tidal forces? Attend the talk and find out!