Answers are grounded in this paper and cite their sources.
The existence of large-scale magnetic fields in galaxies is well established, but there is no accepted mechanism for generating a primordial field which could grow into what is observed today. We discuss a model which attempts to account for the necessary primordial field by invoking a pseudo Goldstone boson coupled to electromagnetism. The evolution of this boson during inflation generates a magnetic field; however, it seems difficult on rather general grounds to obtain fields of sufficient strength on astrophysically interesting scales.
No takes yet. Share an insight, caveat, or question.
Garretson et al. (1992) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: