  The Dynamo effect is used to describe the generation of magnetic fields in
astrophysical objects. However, no rigorous derivation of the dynamo equation
is available. We justify the form of the equation using an Operator Product
Expansion (OPE) of the relevant fields. We also calculate the coefficients of
the OPE series using a dynamic renormalisation group approach and discuss the
time evolution of the initial conditions on the initial seed magnetic field.
