Loss of propulsive force in railguns with laminated containment

The effect of a close-fitting laminated containment structure on propulsive L' is studied both experimentally and computationally. It is shown that the interaction of axial magnetic fields near the armature with the laminations transfers a fraction of the propulsive force to the containment. This reduces the propulsive L' without causing significant reduction in the rail L'. The effect is very sensitive to the spacing between armature and containment. The loss of propulsive force may be as large as 20 to 25% for very close spacing.