PRIMORDIAL MAGNETIC-FIELDS GENERATED IN THE QUARK-HADRON TRANSITION

We propose a mechanism by which magnetic fields of magnitude up to 10( 8) G are generated at the quark-hadron phase transition. The primordia l field is generated by currents formed at the boundaries between the quark and hadron phases, where charge separation occurs. We estimate t he magnetic field generated during this phase and discuss its subseque nt evolution and possible implications at later times. Today, this see d field would have an amplitude less than or similar to 10(-10) muG on scales of approximately 1 pc in the intergalactic medium, and in the galactic interstellar medium it would correspond to less than or simil ar to 10(-5) muG on scales of approximately 10(13) AU and less than or similar to 10(-14) muG on kpc scales. The generated field may act as a seed for galactic and stellar fields.