Anomalous global strings and primordial magnetic fields

We propose a new mechanism for the generation of primordial magnetic fields, making use of the magnetic fields which are induced by anomalous global strings, such as pion and axion strings, which couple to electromagnetism via Wess-Zumino type interactions. We calculate the magnitude and coherence length of these fields. They are seen to depend on the string dynamics. With optimistic assumptions, both the magnitude and coherence scale of the induced magnetic fields can be large enough to explain the seed magnetic fields of greater than 10(-23) G necessary to produce the observed galactic magnetic fields via the galactic dynamo mechanism. [S0556-2821(99)50306-8].