  Using different analytical methods (the quasi-linear approach, the
path-integral technique and tau-relaxation approximation) we develop a
comprehensive mean-field theory for a pumping effect of the mean magnetic field
in homogeneous non-rotating helical turbulence with imposed large-scale shear.
The effective pumping velocity is proportional to the product of alpha effect
and large-scale vorticity associated with the shear, and causes a separation of
the toroidal and poloidal components of the mean magnetic field along the
direction of the mean vorticity. We also perform direct numerical simulations
of sheared turbulence in different ranges of hydrodynamic and magnetic Reynolds
numbers and use a kinematic test-field method to determine the effective
pumping velocity. The results of the numerical simulations are in agreement
with the theoretical predictions.
