Convection-caused symmetry breaking of azimuthal magnetorotational instability in a liquid metal Taylor--Couette flow

Abstract

We report the results of a liquid metal Taylor-Couette experiment in the Rayleigh-stable regime under the influence of an azimuthal magnetic field. We observe that the resulting azimuthal magnetorotational instability (AMRI) from our experimental setup is significantly influenced by the thermal boundary conditions. Even a minimal radial heat flux leads to a symmetry breaking, which results in the AMRI waves traveling either upwards or downwards. We identify the thermal radiation by the central axial current as the heat source responsible for vertical convection in the liquid. Preliminary numerical investigations point towards an interaction between AMRI and thermal convection, which supports our experimental findings.