  The backreaction of the Lorentz force on the alpha-effect is studied in the
limit of small magnetic and fluid Reynolds numbers, using the first order
smoothing approximation (FOSA) to solve both the induction and momentum
equations. Both steady and time dependent forcings are considered. In the low
Reynolds number limit, the velocity and magnetic fields can be expressed
explicitly in terms of the forcing function. The nonlinear alpha-effect is then
shown to be expressible in several equivalent forms in agreement with
formalisms that are used in various closure schemes. On the one hand, one can
express alpha completely in terms of the helical properties of the velocity
field as in traditional FOSA, or, alternatively, as the sum of two terms, a
so-called kinetic alpha-effect and an oppositely signed term proportional to
the helical part of the small scale magnetic field. These results hold for both
steady and time dependent forcing at arbitary strength of the mean field
(abridged).
