Symmetry Breaking of Azimuthal Magnetorotational Instability Caused by Thermal Boundary Conditions


Symmetry Breaking of Azimuthal Magnetorotational Instability Caused by Thermal Boundary Conditions

Seilmayer, M.; Stefani, F.

The first evidence of azimuthal magnetorotaional instability was given some years ago by Seilmayer et al. (2014). A Taylor Couette Setup, filled with liquid metal, was exposed to magnetic field Bφ ~ r^ -1. The necessary current was supplied by a large frame of copper rods which caused a residual m=1 field disturbance. This imperfection caused a stationary dominant background flow. Since then, several changes took place to circumvent external asymmetries and influences. The main improvement was the symmetric current return path which eliminates the m=1 background flow and reduces stray fields. Now the AMRI wave is mainly located at the top of the cylinder, which is surprising since the theoretical prediction allows a symmetric wave with m=±1 configuration. However, the wave component from below is missing. Recent work indicate that thermal convection could be a possible source of symmetry breaking. We present experimental results which give evidence to the strong dependency on thermal boundary conditions which affect AMRI action in the volume.

Keywords: AMRI; MRI; Taylor Couette; magnetorotational instability

  • Poster
    MHD Days and GDRI Dynamo Meeting, 26.-28.11.2018, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-28358
Publ.-Id: 28358