Creating non‐planar static interfaces with magnetic fields Available to Purchase

The possibility of creating experimentally static non‐planar interfaces using magnetic levitation is explored. Placing a cell filled with magnetic fluids between Faraday pole pieces of an electromagnet, we are able to create a magnetic body force acting as an effective gravity. By using permeable wires that perturb the main field, we are able to create a locally uneven but controllable body force at the interface. Under such conditions, even an interface in purely hydrostatic equilibrium ceases to be planar. An initial proof‐of‐concept experiment is made in the Rayleigh‐Taylor instability, where sinusoidal wires are used to create well‐controlled periodic initial perturbations on the interface. Beyond this qualitative demonstration, we conduct here a more systematic quantitative analysis, using numerical calculations in order to determine the expected interface shape for a given shape of permeable wires. The results, combined with the previous experimental demonstration, suggests a promising new technique with the potential to allow, in a near future, the construction of static interfaces of arbitrary shapes.