Electro-thermal behavior of solid armatures

In this paper we discuss the electro-thermal behavior of solid armatures in railguns. This discussion is based on a review of results obtained by a th eory that takes into account the three-dimensional nature of melting and va porizing of the contact surface between rail and armature. This theory is n umerically treated by an integral approach based on a suitable decompositio n of rails and armature in hexahedrons, bricks and filamentary elements. Af ter a recall of the main points of this theory and the related numerical te chnique, this review paper describes the principal features about the curre nt flow, the heat production and exchange, the presence of liquid and vapor phases at the contact face of the armature, derived by this theory. In par ticular the shape of the melt front and the critical transition velocity pr edicted are in agreement with the experimental observations.