Analysis of Rail-Armature Linear Resistance Density as the Characterization Parameter for the Sliding Electrical Contact Performance of the Railgun

The purpose of this article is to find a general parameter that can closely link the research of different-caliber electromagnetic (EM) railguns. In this article, an approximate field scaling method for EM rail launchers is proposed under the condition of matching the dynamic parameters of the projectile, which provides guidance for a suitable subscale test of an EM railgun. Through theoretical analysis and formula derivation, the concept of "rail-armature linear resistance density" is put forward. It is defined as: the contact resistance per unit length along the moving direction of the armature on the contact surface between the armature and the rail of the EM railgun. Through multiple launching tests and calculation of the rail-armature linear resistance density for different-caliber launchers, the rail-armature linear resistance density can be used as a characteristic parameter for the sliding electrical contact performance of the EM railgun in the case of linear current density approximation.