  The effect of shear on the growth of large scale magnetic fields in helical
turbulence is investigated. The resulting large-scale magnetic field is also
helical and continues to evolve, after saturation of the small scale field, on
a slow resistive time scale. This is a consequence of magnetic helicity
conservation. Because of shear, the time scale needed to reach an
equipartition-strength large scale field is shortened proportionally to the
ratio of the resulting toroidal to poloidal large scale fields.
