  The asymptotic behavior of the equilibrium radiation in Maxwellian plasma is
investigated for the region of low frequencies. It is shown, that already for a
weakly non-ideal plasma the equilibrium radiation can essentially deviate from
the Planck law. The deviation from the Planck distribution is described by the
transverse dielectric permittivity which takes into account both frequency and
spatial dispersion. The influence of plasma non-ideality increases with
increase of the non-ideality parameter in the in the dielectric permittivity.
The spectral energy distribution of the equilibrium radiation essentially
changes in the region of observable frequencies. At asymptotically low
frequencies there is transfer from logarithmic to power behavior of the
equilibrium radiation. The results indicate that in the primordial plasma of
Early Universe the spectral energy distribution of radiation could be different
then the Planck one.
