Tungsten wire array number scan studies with the 100-ns, 20-MA Z accelerator*

A systematic experimental investigation of the effect of the tungsten interwire gap spacing (IWG) on initiation, implosion dynamics and quality of the 100-ns fast wire array z-pinch has been conducted. The wire array dimensions and mass are those of interest for the z-pinch driven ICF program. Namely, the diameter is 20mm, the height 10mm, and the mass 5.8mg. Up to now, wire arrays containing 50, 120, 194, 300, and 500 wires have been imploded. Most of the Z accelerator radial line of sight diagnostics were fielded, including XRD’s, PCD’s, bolometers, calorimeters, spectrometers, and x-ray imaging time resolved pinhole cameras. The x-ray radiated energy and power increases with wire number while the rise time and FWHM decreases. Preliminary analysis of the x-ray images suggests that the wires in the 50 wire array remain discreet and visible (not merged) until pinch time while with 120 and higher wire number, wire appear merged. Experimental results will be presented and analyzed and compared with numerical simulations. * Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94-AL85000.