Abstract
We report the first direct evidence for the axisymmetric standard magnetorotational instability (SMRI) from a combined experimental and numerical study of a magnetized liquid-metal shear flow in a Taylor-Couette cell with independently rotating and electrically conducting end caps. When a uniform vertical magnetic field is applied along the rotation axis, the measured radial magnetic field on the inner cylinder increases linearly with a small magnetic Reynolds number due to the magnetization of the residue Ekman circulation. Onset of the axisymmetric SMRI is identified from the nonlinear increase of beyond a critical in both experiments and nonlinear numerical simulations. The axisymmetric SMRI exists only at sufficiently large and intermediate , a feature consistent with theoretical predictions. Our simulations further show that the axisymmetric SMRI causes the velocity and magnetic fields to contribute an outward flux of axial angular momentum in the bulk region, just as it should in accretion disks.
- Received 8 April 2022
- Revised 14 June 2022
- Accepted 21 July 2022
DOI:https://doi.org/10.1103/PhysRevLett.129.115001
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
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