  We propose a mechanism to generate large-scale magnetic fields with
correlation lengths of 100 kpc. Domain walls with QCD scale internal structure
form and coalesce obtaining Hubble scale correlations and align nucleon spins.
Due to strong CP violation, nucleons in these walls have anomalous electric and
magnetic dipole moments and thus the walls are ferromagnetic. This induces
electromagnetic fields with Hubble size correlations. The same CP violation
also induces a maximal helicity (Chern-Simons) correlated through the Hubble
volume which supports an inverse cascade allowing the initial correlations to
grow to 100 kpc today. We estimate the generated electromagnetic fields in
terms of the QCD parameters and discuss the effects of the resulting fields.
