Experimental results on magnetorotational instability

The magnetorotational instability (MRI) plays a key role in the formation of stars and black holes, by enabling outward angular momentum transport in accretion disks. A recent paper [R. Hollerbach and G. Rüdiger, Phys. Rev. Lett., Vol. 95, 124501 (2005)] has shown that the threshold for the onset of the MRI in a liquid metal Taylor-Couette flow is dramatically reduced if both axial and azimuthal magnetic fields are imposed. In agreement with this prediction, a variety of experimental results of a Taylor-Couette experiment with the liquid metal alloy GaInSn is presented, showing evidence for the existence of the MRI at Reynolds numbers of order 1000 and Hartmann numbers of order 10.