  A central quantity in mean-field magnetohydrodynamics is the mean
electromotive force EMF, which in general depends on the mean magnetic field.
It may however have a part independent of the mean magnetic field. Here we
study an example of a rotating conducting body of turbulent fluid with non-zero
cross-helicity, in which a contribution to the EMF proportional to the angular
velocity occurs (Yoshizawa 1990). If the forcing is helical, it also leads to
an alpha effect, and large-scale magnetic fields can be generated. For not too
rapid rotation, the field configuration is such that Yoshizawa's contribution
to the EMF is considerably reduced compared to the case without alpha effect.
In that case, large-scale flows are also found to be generated.
