Abstract: A 3D transient electromagnetic field model is developed to investigate the characteristics of magnetic field in railgun. The proposed model is solved by a time-domain finite element and boundary-element coupling method. The kinematic process of armature in bore and the space-time distributions of current density and magnetic flux density were obtained. Velocity shin effect due to sliding electrical contact between armature and rails during current diffusion is discussed. In the launch experiment, a B-dot probe is used to measure the armature motion and magnetic filed. The characteristics of change in transient magnetic filed during launch are analyzed. 3D transient electromagnetic filed model of railgun is validated by comparison of experimental results with numerical simulation.

Key words: ordnance science and technology, railgun, electromagnetic field, B-dot probe, finite element, numerical calculation