Experimental observation of the rail resistance contribution to muzzle voltage

In 1994, Dreizin and Barber [1] presented an analysis of the muzzle voltage developed in a railgun with a solid contact armature. They showed that the re is a significant contribution to the measured muzzle voltage arising fro m the current how in the rails ahead of the armature. They further argued t hat this voltage is influenced by velocity skin effect and that it may beco me the dominant effect on muzzle voltage at high velocity, The results of that paper, although on solid theoretical foundations, gener ated some controversy because many previous investigations of armature beha vior had obtained good agreement between theory and observation without tak ing this term into account. In this paper, a novel experimental technique is described that permits dir ect observation of the effect of precursor rail current on muzzle voltage. The observed magnitude of the voltage is in agreement with the estimates pr ovided by Dreizin and Barber, including the contribution of velocity skin e ffect.