Development of Small-Bore, High Current-Density Railgun as TestBed for Study of Plasma-Materials Interaction. (Report for October 16, 2000-May 13, 2003)

摘要

This report summarizes the research progress made during the period October 16,2002 through May 13,2003 toward the development of a small-bore railgun with transaugmentation as a testbed for investigating plasma-materials interaction. Since this advanced compact gun can independently control the speed and properties of free-traveling plasma arc, assessing its feasibility as a testbed for studying plasma-materials interaction was warranted. Gun wall erosion and ablation and the resulting impurities that accumulate in the plasma-arc were controlled by separately varying the respective currents in the main rail and the transaugmentation rail, and the gas fill pressure. The impurities were investigated by measuring the variation in the arc velocity along the length of the railgun and the emission spectrum of the arc. The equation of motion of the plasma arc was solved to elucidate the correlation between the physical properties (density and temperature) and dynamical behavior (velocity) of the plasma arc and the erosion property of the railgun wall materials. Due to the limited funding ($40K for the entire period) the work performed could not be extensive, however, it has generated ample evidence indicating that the transaugmented compact railgun may very well serve as a powerful tool for studying plasma-materials interaction.