Influence of Pulse Shaping for a 10-MJ Electromagnetic Launcher

During a railgun launch with capacitive energy as a primary source, the energy is converted into kinetic energy, inductive energy, and resistive losses in the system, the kinetic energy being the main value to optimize. The magnitude and the speed of this conversion process highly depend on the characteristics of the pulse shape. The objective of this study is to experimentally and theoretically determine the influence of the pulse shaping on this conversion process. Recent experimental campaigns led at the French–German Research Institute (ISL) involving the railgun experimental facility NGL-60, featuring convex rails and a 60-mm caliber, aimed at comparing two different pulse shaping strategies. One consists of an initial simultaneous triggering of all the capacitor banks, provoking an initial surge of current in the system followed by a decay, the other involving a regulated activation of the different capacitor banks, resulting in a smooth shape of the current pulse. These two pulses are tested at different initial capacitive energies with masses ranging between grams and kilograms and the results are analyzed by evaluating the different energy quantities evolution during the conversion process. These results give an insight on how to optimize the delivered pulse shape depending on the railgun facility characteristics.