Neutrino-electron magnetohydrodynamics in an expanding universe

We derive a new model for neutrino-plasma interactions in an expanding universe that incorporates the collective effects of neutrinos on plasma constituents. start from kinetic description multi-species flat Friedmann-Robertson-Walker metric, where particles are coupled to through charged- and neutral-current forms weak interaction. then fluid equations specialize our (a) lepton epoch, we consider pair electron-positron interacting with electron (anti-)neutrinos, (b) after annihilation, electron-proton take limit slow ions inertia-less electrons obtain set neutrino-electron magnetohydrodynamics (NEMHD) equations. In both models, dynamics is affected by neutrino motion ponderomotive force and, as result, terms appear induction equation can act source magnetic field generation early universe. A brief discussion possible applications proposed.