Gas puff implosion measurements and modeling

Summary form only given as follows. Hawk is an inductive store, plasma opening switch driven generator, used at NRL for plasma radiation source (PRS) experiments. The current, in the neon PRS rises to 600-700 kA in 50-100 ns and produces /spl sim/150 Joules/cm of K-shell radiation. Two-dimensional images are obtained using a shearing interferometer (/spl lambda/=532 nm), these images show a current sheath and instability structure. Pinch current and final X-ray pulse are measured in conjunction with the interferometry. The initial gas profile is measured at three axial locations, using a separate high-sensitivity interferometer in a test stand configuration after the PRS experiments. The gas profile is a hollow shell with a nozzle exit diameter of 3.5 cm. A simple ballistic gas-flow model is used as an analytic fit to the gas flow measurements. Computationally, this fit to the gas flow is then snowplow imploded radially at several axial locations, using the measured pinch current. The pinch radius as a function of time predicted from this simulation is compared to that observed via shearing interferometry. Measured K-shell radiation output is compared with the predicted output from a two-level K-shell X-radiation model.