3-D MHD simulation of a railgun hybrid armature

A 3-D plasma MHD code MAP3 was developed to simulate the flow in railgun plasma armatures. MAP3 has now been used to simulate qualitatively the plasma flow around a hybrid armature. The first simulation considered an aluminum hybrid armature in a 1-cm square bore, similar to the conditions for hybrid armature experiments performed earlier at UTSL. Simulation results agree with flow paths observed visually on the recovered experimental armatures at UTSL. The second simulation considered a hybrid armature in a 2-cm square bore. The fraction of the current carried in the solid armature increases with the bore dimension, which is consistent with experimental observations.