Role of Induced Fields in Railguns

We provide an analysis of the nature of emfs induced during the operation of a railgun. The focus here is on the railguns, but the results are applicable to a broad range of similar distributed parameter problems. The main sources of induced emfs are current changes and armature motion. New perspectives are presented. It is shown, for example, that there is no true motional emf in railguns, and an alternative approach is offered in terms of localized flux creation. COMSOL modeling is used to illustrate the main concepts and consequences of induced emfs, and to validate the analyses. Experimental data provide added validation. The results offer insights into previously unexplained phenomena commonly observed in railgun tests.