Ap. Martin et Ac. Davis, THE STABILITY OF PRIMORDIAL MAGNETIC-FIELDS PRODUCED BY PHASE-TRANSITIONS, Physics letters. Section B, 360(1-2), 1995, pp. 71-76
Primordial magnetic fields seem to be a generic relic of phase transit
ions in the early universe. We consider a primordial electromagnetic f
ield formed as a result of a second-order phase transition, and show t
hat it is stable to thermal fluctuations in the period immediately fol
lowing. We also show how such a field arises in first order phase tran
sitions. In both cases there is a transitive electric field produced d
uring the transition.