New methods to reduce the erosion of bore in a small bore railgun

Erosion of the bore surface is a fatal problem for the repetitive operation of the railgun accelerators. Preaccelerators such as pneumatic guns, electrothermal guns and so on are generally used to reduce the erosion. Here, two ideas to reduce the erosion are proposed and experimentally confirmed using a small railgun which has 5 mm square bore. One is the method of a plasma initiation separated from the projectile (PISP method), the otheris the augmentation of the magnetic field by using a permanent magnet. The erosion of bore surface was reduced dramatically by applying those two ideas, and the performance of the railgun was improved.