Speaker
Description
COBRA, the 1 million ampere pulsed power facility at Cornell University, enables detailed investigation into magnetically driven implosions of structured cylindrical gas-puff z-pinches thanks to an extensive suite of diagnostics. Such implosions, without an applied axial magnetic field, hold promise as intense x-ray or neutron sources and, with an applied magnetic field, may be of interest for magneto-inertial fusion studies. Here we present observations from 7 cm initial diameter, triple nozzle gas-puff z-pinch experiments of shock dynamics and Magneto-Rayleigh-Taylor (MRT) instability growth leading up to the stagnation of the pinch. In particular, we investigate the effects of gas species, initial radial density profile, and axial magnetic fields on shock structure and MRT growth rates. Diagnostics include: planar laser-induced fluorescence, which provides a measure of the initial neutral gas density profile of the load; three-frame laser shearing interferometry to resolve the local electron density and shock structure; gated extreme ultraviolet (XUV) cameras which reveal the time evolution of the gas puff structure; filtered x-ray pinhole cameras to image the pinch plasma; and photoconducting diamond detectors (PCDs) to measure x-ray emission at various wavelengths. Good agreement is found when the experimental data are compared to simple numerical z-pinch model predictions.
