Peculiarities of milligram mass acceleration in electromagnetic railguns with an external pulsed magnetic field

Solid polycarbonate impactors were accelerated in a channel of electromagnetic railgun to which an external pulsed magnetic field was applied. The channel was filled with air at atmospheric pressure. The dynamics of impactor acceleration in the railgun was calculated. The impactor velocities in the railgun muzzle were measured in two cases. In the first case the railgun and external field system were powered from independent energy sources (scheme 1) and in the second case the railgun and external field circuits were connected in series to a common energy source (scheme 2). It was established that the effective coefficient of rail erosion in a 2-mm caliber channel that takes into account only the eroded mass captured by the plasma piston was 1.5–1.7 mg/C, and the eroded mass involved in the motion was comparable with the impactor mass. It was shown that in scheme 1, when the external field system was switched earlier, the impactor was accelerated at a maximum magnetic induction, and the impactor velocity in the channel muzzle exceeded 6 km/s.