Creating non-planar static interfaces with magnetic fields Creating non-planar static interfaces with magnetic fields
Résumé
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.