  The nonlinear coefficients defining the mean electromotive force (i.e., the
nonlinear turbulent magnetic diffusion, the nonlinear effective velocity, the
nonlinear kappa-tensor, etc.) are calculated for an anisotropic turbulence. A
particular case of an anisotropic background turbulence (i.e., the turbulence
with zero mean magnetic field) with one preferential direction is considered.
It is shown that the toroidal and poloidal magnetic fields have different
nonlinear turbulent magnetic diffusion coefficients. It is demonstrated that
even for a homogeneous turbulence there is a nonlinear effective velocity which
exhibits diamagnetic or paramagnetic properties depending on anisotropy of
turbulence and level of magnetic fluctuations in the background turbulence.
Analysis shows that an anisotropy of turbulence strongly affects the nonlinear
mean electromotive force. Two types of nonlinearities (algebraic and dynamic)
are also discussed. The algebraic nonlinearity implies a nonlinear dependence
of the mean electromotive force on the mean magnetic field. The dynamic
nonlinearity is determined by a differential equation for the magnetic part of
the alpha-effect. It is shown that for the alpha-Omega axisymmetric dynamo the
algebraic nonlinearity alone cannot saturate the dynamo generated mean magnetic
field while the combined effect of the algebraic and dynamic nonlinearities
limits the mean magnetic field growth. Astrophysical applications of the
obtained results are discussed.
