Analysis of In-Bore Magnetic Field for Railguns at Zero Speed

A two-dimensional transient computational model was built in this paper to analyse the in-bore magnetic field. The current density in the rails and armature had been calculated by solving the reduced magnetic-diffusion equation. Through the calculated current density and the Biot and Savart´s law, the in-bore magnetic field had been calculated. The results show the concentration of current occurs at the left-hand edge of the rail -- armature interface initially, then the current spread to the internal conductor within 1ms. The field point which closer to the origin coordinate has higher value of magneitc flux density.