Abstract: An improved electromagnetic launcher (10; 98; 150) has a barrel (20; 100) formed by at least one pair of bus-bars (30, 32; 102, 104; 156, 158; 184, 184, 188, 190) to transport current longitudinally along the barrel. The barrel includes a bore (36; 108) which is spaced from the bus-bars by a bore structure (34; 106). The bore structure guides an elongated, tapered metal armature (44; 122; 164) through the bore. The current to the armature passes from the bus-bars through an array of deformable contactors (54, 55; 110, 112) disposed near the bore walls and in series with resistors (60, 62, 64, 66; 114, 116, 118, 120). The resistors distribute current and electromagnetic driving force along the armature. A conductive implodable shield (130) confines the bore structure and the bus-bars to impede repulsion of the bus-bars and to compress the magnetic flux between the shield walls and the bus-bars.

Abstract: A railgun apparatus for accelerating a projectile having a conductive region. The railgun comprises a power supply for providing a current impulse and at least two elongate generally parallel rails. The rails include a first layer comprising a highly conductive material and a second layer comprising a highly resistive layer. The second layer has a resistivity that varies along the length of the rails and is so sized and arranged as to contact the conductive region of the projectile. The power supply is switchably connected to the first layer of the rails. When the current impulse is applied to the rails with the projectile therebetween, the current impulse is spread over the conductive region of the projectile to reduce the velocity skin effect.