PROTOGALACTIC EVOLUTION AND MAGNETIC-FIELDS

We show that the relatively strong magnetic fields (greater than or eq ual to 1 mu G) in high redshift objects can be explained by the combin ed action of an evolving protogalactic fluctuation and electrodynamic processes providing the magnetic seed fields. Three different seed fie ld mechanisms are reviewed and incorporated into a spherical ''top-hat '' model and tidal torque theory for the fate of a forming galaxy in a n expanding universe. Very weak fields 10(-19) similar to 10(-23)G cre ated in an expanding over-dense region are strongly enhanced due to th e dissipative disk formation by a factor similar to 10(4), and subsequ ently amplified by strong non-axisymmetric flow by a factor similar to 10(6-10), depending on the cosmological parameters and the epoch of g alaxy formation. The resulting field strength at z similar to 0.395 ca n be of the order of a few mu G and be close to this value at z simila r to 2.