Experimental characterization of railgun-driven supersonic plasma jets motivated by high energy density physics applications

摘要

We report experimental results on the parameters, structure, and evolution ofhigh-Mach-number (M) argon plasma jets formed and launched by apulsed-power-driven railgun. The nominal initial average jet parameters in thedata set analyzed are density pprox 2 x 10^(16) cm^(-3), electron temperaturepprox 1.4 eV, velocity pprox 30 km/s, M pprox 14, ionization fractionpprox 0.96, diameter pprox 5 cm, and length pprox 20 cm. These valuesapproach the range needed by the Plasma Liner Experiment (PLX), which isdesigned to use merging plasma jets to form imploding spherical plasma linersthat can reach peak pressures of 0.1-1 Mbar at stagnation. As these jetspropagate a distance of approximately 40 cm, the average density drops by oneorder of magnitude, which is at the very low end of the 8-160 times droppredicted by ideal hydrodynamic theory of a constant-M jet.