  We study the possibility of generating magnetic fields during the evolution
of electron, proton, and photon plasma in the pre-recombination era. We show
that a small magnetic field can be generated in the second order of
perturbation theory for scalar modes with adiabatic initial conditions. The
amplitude of the field is $\la 10^{-30} \rm G$ at the present epoch for scales
from sub-kpc to $\ga 100 \rm Mpc$.
