A 3-D numerical study of a 1-cm bore plasma railgun

Summary form only given. A 3-D plasma MHD code MAP3 (MHD Arc Plasma) was developed at University of Tennessee Space Institute (UTSI) to simulate the flow in a railgun plasma armature. The code includes a viscous Navier-Stokes fluid model for the plasma flow. It is coupled to a quasi-static Maxwell´s equations model for the electromagnetic field. Diffusive radiation transfer and ablation are also simulated. Preliminary results of the MAP3 calculation for the plasma armature railgun in a 2-cm bore have shown important features of the plasma flow which could not be predicted by previous 2-D numerical models. In particular, the motion of the armature and 3-D electromagnetic effects lead to spatial nonuniformity of the Lorentz force. The resulting plasma flow is directed away from the projectile along the axis of symmetry. This is exactly the opposite to results obtained from 2-D simulations. Hot materials carried away from the armature tend to elongate the current distribution. This may be a precursor to the development of secondary armatures. MAP3 has now been used to simulate a 1-cm bore plasma armature railgun. The aim of the present work is to further study possible secondary are development resulting from 3-D plasmadynamical phenomena. Conditions experimentally known as being favorable for secondary arc development have been simulated.