High opacity effects in multi-milligram aluminum wire array implosions

Summary form only given. High mass aluminum wire array implosions have been performed on Z to provide data on the parameters of the stagnated high opacity plasma. The aluminum wire arrays were composed of 300 wires on a 20-mm diameter with a total mass loading of 6050 /spl mu/g/cm. The aluminum alloy used, 5056, had 5% Mg by mass. The measured total X-ray emissions had a yield of 1400 kJ and power of 60 TW. The aluminum and magnesium K-shell emissions combined only totaled 100 kJ, with the spectra indicating very strong continua above and below the K-shell recombination edges. The intense continua (30% of the peak line intensities) are strong indications of high opacities, as were the large ratio of Mg to Al lines, and the presence of strong absorption features in the spectra, especially in the lower energy side of the helium-alpha lines, where many of the satellites lie. Spectral analyses have been performed indicating that only a few percent of the initial mass is heated to temperatures that excite K-shell lines. The remaining mass causes significant absorption of the K-shell emissions. These analyses produce a picture of the mass distribution in the stagnated plasma. In this paper, we present these analyses, along with comparisons to detailed 1-dimensional (1-D) radiation-magneto-hydrodynamic calculations, and 2-D MHD calculations. Many aspects of these implosions may require 3-D calculations in the future.