The interaction of supersonic laser-generated plasma jets with a secondary gas target was studied experimentally. The plasma parameters of the jet, and the resulting shock, were characterized using a combination of multi-frame interferometry/shadowgraphy, and x-ray diagnostics, allowing for a detailed study of their structure and evolution. The velocity was obtained with an x-ray streak camera, and filtered x-ray pinhole imaging was used to infer the electron temperature of the jet and shock. The topology of the ambient plasma density was found to have a significant effect on the jet and shock formation, as well as on their radiation characteristics. The experimental results were compared with radiation hydrodynamic simulations, thereby providing further insights into the underlying physical processes of the jet and shock formation and evolution.

Computer modeling of fast capillary discharge is performed to investigate a new laser active medium created by excited hydrogenlike boron ions leading to lasing at 26.23 nm. Recombination excitation of the boron ions is expected in the undercooled pinching plasma created during the expansion phase of the pinch. Plasma dynamics is described by the magnetohydrodynamic code NPINCH and the plasma ion kinetics is evaluated according to the FLY code. Results of simulations for capillary filled with boron are reported and compared with previous results achieved for nitrogen filled capillary. In both cases, the same nonablative capillary with radius of 1.6 mm is presumed and the current pulse with 50 kA peak value and 10 12 A s −1 current slope are taken into account. Evaluated pressure optimized gains are 1.04 and 0.11 cm −1 are found for boron and nitrogen filled capillary, respectively. Capillary wall ablation is then also assayed.

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