Characterization of plasma jets driven by a small linear railgun

Abstract

This paper reports measured and inferred characteristics of plasma jets produced by a 10-cm plasma-armature railgun designed to provide a platform to study phenomena associated with high-Mach-number plasma flows. This gas-fed accelerator is powered by an underdamped LC pulse-forming network (PFN) operated at charge voltages up to 15 kV and fired into a large cylindrical vacuum chamber, emitting a series of plasma jets which propagate into the chamber. Analysis of data captured by an interferometer and spectrometer at locations 10 and 40 cm away from the railgun's bore suggests jet velocities between 14.5 and 19.7 km/s, electron number densities between 3.4 × 1014 and 2.5 × 1016 cm−3, a plasma temperature of approximately 2 eV, and Mach number between 5.1 and 7.0. These parameters fall in a parameter space conducive to the study of shock structures in multi-ion-species plasmas, as the ion stopping distances and consequently shock thicknesses are expected in the several millimeter to few-centimeter range.