Numerical simulation of the non-axisymmetric magneto-rotational instability in a dominantly azimuthal magnetic field

In a Taylor-Couette experiment on the non-axisymmetric version of the magnetorotational instability, performed by Seilmayer et al. [1], a dominantly azimuthal magnetic field was created by a central vertical copper rod connected to the power source by two horizontal rods at a height of approximately 0.8 m below and above the cylindrical volume. The liquid metal flow in the cylindrical gap between the cylinders was simulated using the OpenFoam library including a Poisson equation for the determination of the induced electric potential. The slight deviation from a purely axisymmetric azimuthal imposed magnetic field turns out to have a surprisingly strong effect on both the critical Hartmann number and the flow structure of the instability.