Radiation signatures of large sized multi-planar wire arrays

Summary form only given. Experiments on the Zebra generator with LCM (Load Current Multiplier, provides 1.5-1.7 MA) allow for implosions of larger sized wire array loads (including planar wire arrays) than at standard current of 1 MA. Advantages of larger sized planar wire array implosions include enhanced energy coupling to plasmas and better diagnostic access to observable plasma regions. A full set of diagnostics was implemented to study radiation in a broad spectral range from few Å to few hundred Å using PCD, XRD, and EUV detectors, X-ray/EUV spectrometers and X-ray pinhole cameras. In addition, laser shadowgraphy was utilized. In multi-planar wire arrays, two outer wire planes were each 4.9 mm width and made of eight mid-atomic-number (Alumel with 95% of Ni) wires with the inter-row gap increased from 3 or 6 mm (usually used at 1 MA current) up to 9 mm. A central plane located in the middle between the outer planes had empty slots and a few Al wires at the edges. Recently, we have shown that such configuration produces higher linear radiation yield. In the new experiments, the number of empty slots was further increased from 6 up to 10, increasing the gap inside the middle plane from 4.9 to 7.7 mm, respectively. This allows for more independent study of the flows of L-shell Ni plasma (between the outer planes) and K-shell Al plasma (which first fills the gap between the edge wires along the middle plane) and their radiation in space and time. When studying the combined wire arrays before, the time-gated X-ray spectra have always included radiation from both materials, even at early time. In the present work, for the first time we have observed that the K-shell Al radiation was delayed compared to L-shell Ni radiation when the number of empty slots was increased. In addition, the results of another new experiment are presented when a few Al wires on each edge were replaced by a thicker Cu wire to understand their influence on radiation from out- r planes.