Electromagnetic radiation of railgun and shielding effects from its structures

The Navy railgun propels its projectile with Lorentz force, and is capable of delivering Mach 7–8 speed for ∼15kg weight projectiles. The source of the Lorentz force is a GW pulsed power supply (PPS) that delivers ∼1MA current with ∼10KV voltage into the railgun load. The electromagnetic radiation of railgun, though most shielded by its metallic cover, leaks out at the final stage when the projectile leaves the barrel and can be a possible EMC issue for on board electronics. We analyse the EM radiation coming from rails and armature of the railgun, and evaluate the shielding effectiveness of various components, also present the far and near field radiation patterns at the final stage of firing. We found most of the forward far field radiation is concentrated at the bore-sight direction due to outside metal casing shielding, and a strong backward far field exists in breech direction due to impedance mismatch between PPS and railgun.