Determining the Effect of an Arc in a Railgun Bore on Emission Efficiency Using B-Dot Probes

The unexpected arcs generated in a railgun bore are one of the major issues affecting emission efficiency. To study the impact of such arcs, a series of experiments with the same launch parameters has been conducted. B-dot probes positioned along the length of the launcher provide data for detecting arc formation phenomena and for measuring the armature velocity. In this paper, two sets of typical signals are discussed. The first set of signals is normal, whereas the other is abnormal in terms of the existence of an arc in the bore during launch. The time interval during which the arc generated and the state of the arc are determined from the magnetic induction curves by integrating the B-dot probe signals. Using a fitting analysis, the displacements and velocities of the armatures are obtained, and the energy distribution of each shot is computed. The results indicate that the generation of an arc in the bore causes a hash launch environment and greatly reduces the emission efficiency.