Rail and armature current distributions in electromagnetic launchers

Abstract

The current and magnetic field distributions in the rails and armature of an electromagnetic launcher are obtained in closed form for the steady state. These solutions assume that the armature moves with a steady velocity and account fully for the two-dimensional skin effect caused by the relative motion between the rails and the armature. Both solid and laminated armatures are considered. It is found in the case of the laminated armature that the phenomenon can be described by a single dimensionless parameter, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\frac{\ell}{w}\frac{\sigma_{o}}{\sigma_{r}}\sqrt{\frac{u\ell}{\pi\eta_{r}}}</tex> .