High Magnetic Shear Gain in a Liquid Sodium Stable Couette Flow
  Experiment; A Prelude to an alpha-Omega Dynamo
  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, $B_{\phi} \simeq 8\times B_r$ 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.
