Understanding Large-Scale Dynamos in Unstratified Rotating Shear Flows
Abstract
We combine simulations with new analyses that overcome previous pitfalls to explicate how nonhelical mean-field dynamos grow and saturate in unstratified, magnetorotationally driven turbulence. Shear of the mean radial magnetic field amplifies the azimuthal component. Radial fields are regenerated by velocity fluctuations that induce shear of radial magnetic fluctuations, followed by Lorentz and Coriolis forces that source a negative off-diagonal component in the turbulent diffusivity tensor. We present a simple schematic to illustrate this dynamo growth. A different part of the Lorentz force forms a third-order correlator in the mean electromotive force that saturates the dynamo.
Fields of Study & Subjects
Geomagnetism and Paleomagnetism Studies
Fluid dynamics and aerodynamics studies
Fluid Dynamics and Turbulent Flows
Publication details
- Journal / source
- Physical Review Letters
- Volume
- 136
- Issue
- 7
- Pages
- 075201–075201
- Publication date
- 7 January 2026
- Language
- EN