Global versus local cosmic strings from pseudo-anomalous U(1)

We study the structure of cosmic strings produced at the breaking of an ano malous U(1) gauge symmetry present in many superstring compactification mod els. We show that their coupling with the axion necessary in order to cance l the anomalies does not prevent them from being local, even though their e nergy per unit length is found to diverge logarithmically. We discuss the f ormation of such strings and the phenomenological constraints that apply to their parameters. (C) 1998 Published by Elsevier Science B.V. All rights r eserved.