New results on planar wire array implosions and their comparison with cylindrical wire arrays on the 1 MA zebra generator

Abstract

Planar wire arrays were shown to produce the strong power and yield in EUV/x-ray region 1 . The new results of the total radiation yield E t , time-resolved sub-keV and keV outputs, xray spectra and images from ten wire planar arrays from lowto high-Z a materials were collected recently on Zebra at UNR. Data were compared with the similar mass cylindrical wire arrays results. Planar arrays were characterized by a short rise-time of a single radiation peak: up to 8 ns for sub-keV radiation and near 2 ns in keV and harder x-ray regions, and much higher peak power compared to cylindrical arrays usually having precursor and main peak with a fastest risetime > 10-15 ns. The largest E t >18 kJ was found for Cu and Mo planar arrays (up to 25% from an energy delivered to a load) that is higher than a maximum E t ≈15-16 kJ for Cu or 10 kJ for Alumel (Ni) cylindrical arrays. The radiating imploding plasma is strongly inhomogeneous. The plasma (few-mm thick in the EUV/sub-keV region) has within itself hundred-μm scale structures on the axis (in several keV quanta). The electron temperatures up to 800-1000 eV were estimated for Mo planar arrays that are much higher than for cylindrical arrays and comparable with the values for Xpinches. The implosion dynamics of wire arrays were studied using spectral and imaging techniques. The results were compared with radiation and MHD modeling.