Ohmic currents and pre-decoupling magnetism

Ohmic currents induced prior to decoupling are investigated in a standard transport model accounting both for the expansion of the background geometry as well as of its relativistic inhomogeneities. The relative balance of the Ohmic electric fields in comparison with the Hall and thermoelectric contributions is specifically addressed. The impact of the Ohmic currents on the evolution of curvature perturbations is discussed numerically and it is shown to depend explicitly upon the evolution of the conductivity.