The Maximum Theoretical Efficiency of Constant Inductance Gradient Electromagnetic Launchers

The maximum theoretical efficiency of constant inductance gradient electromagnetic launchers (EMLs) is analyzed and discussed. The maximum theoretical efficiency is a parameter needed to calculate the EML's efficiency. Constant inductance gradient EMLs include the conventional railgun, the augmented railgun, and the conventional helical launcher. The maximum theoretical efficiency of an EML is dependent on its geometry and the manner, or mode, in which it is powered. In the lossless case, the conventional railgun, the augmented railgun, and the conventional helical launcher are capable of 50% maximum efficiency when operating in constant current (CC) mode. Conventional and augmented railguns can achieve 100% maximum efficiency when operating in zero exit-current mode. While zero exit-current mode promotes high efficiency, this mode can reduce EML lifetime since it requires current levels much higher than those found in CC mode. The high-efficiency helical launcher, presented and analyzed here for the first time, combines 100% maximum theoretical efficiency with the low-current benefits of constant-current mode.