Experimental evidence for collisional shock formation via two obliquely merging supersonic plasma jets

We report spatially resolved measurements of the oblique merging of two supersonic laboratory plasma jets. The jets are formed and launched by pulsed-power-driven railguns using injected argon, and have electron density similar to 10(14) cm(-3), electron temperature approximate to 1.4 eV, ionization fraction near unity, and velocity approximate to 40 km/s just prior to merging. The jet merging produces a few-cm-thick stagnation layer, as observed in both fast-framing camera images and multi-chord interferometer data, consistent with collisional shock formation [E. C. Merritt et al., Phys. Rev. Lett. 111, 085003 (2013)]. (C) 2014 AIP Publishing LLC.