Can the efficiency of an electrostatic to kinetic energy conversion process exceed 50%? [EM launchers]

The paper presents a careful theoretical examination of the possibility that more than one-half of the energy stored in a power capacitor can be converted into the kinetic energy of a moving conductor. A number of conclusions arising from the study are implemented practically in a simple geometry, for which a two-dimensional modelling is used to predict the theoretical performance. Statements appearing elsewhere in the literature suggest that an efficiency of 50% can be obtained from an electromagnetic launcher fed from a capacitor energy source, although these do not appear to have been substantiated experimentally. A number of different launchers have been described and analysed, but to the best of the authors´ knowledge the best efficiencies so far obtained are only a little in excess of 40%. Results from a series of ongoing launcher experiments, guided by the two-dimensional code, are therefore presented. Efficiencies very close to 50% have already been obtained, and planned experiments are described that are designed to demonstrate that a predicted efficiency exceeding 50% can be confirmed in practice.