High Magnetic Shear Gain in a Liquid Sodium Stable Couette Flow Experiment; A Prelude to an alpha-Omega Dynamo

Abstract

The $\Omega$-phase of the liquid sodium $\alpha$-$\Omega$ dynamo experiment at NMIMT in cooperation with LANL has successfully demonstrated the production of a high toroidal field, $B_{\varphi }\simeq 8\times B_r$ from the radial component of an applied poloidal magnetic field, $B_r$. This enhanced toroidal field is produced by rotational shear in stable Couette flow within liquid sodium at $Rm\simeq 120$. The small turbulence in stable Taylor-Couette flow is caused by Ekman flow where $(\delta v/v{)}^2\sim 10^{-3}$. This high $\Omega$-gain in low turbulence flow contrasts with a smaller $\Omega$-gain in higher turbulence, Helmholtz-unstable shear flows. This result supports the ansatz that large scale astrophysical magnetic fields are created within semi-coherent large scale motions in which turbulence plays only a smaller diffusive role that enables magnetic flux linkage.

5 pages, 5 figures, submitted PRL revised version: add one author, minor typo's

References in corpus (4)

• Generation of magnetic field by dynamo action in a turbulent flow of liquid sodium
• Impact of impellers on the axisymmetric magnetic mode in the VKS2 dynamo experiment
• A Magnetic Alpha-Omega Dynamo in Active Galactic Nuclei Disks: II. Magnetic Field Generation, Theories and Simulations
• A Magnetic Alpha-Omega Dynamo in Active Galactic Nuclei Disks: I. The Hydrodynamics of Star-Disk Collisions and Keplerian Flow

Cited by in corpus (6)

• Magnetic induction and diffusion mechanisms in a liquid sodium spherical Couette experiment
• Nonlinear dynamo in a short Taylor-Couette setup
• Instabilities of rotational flows in azimuthal magnetic fields of arbitrary radial dependence
• Laboratory experiments on dynamo action and magnetically triggered flow instabilities
• Biographical Memoir of Stirling Colgate
• Phase Slip Solutions in Magnetically Modulated Taylor-Couette Flow