10-mm radius tungsten wire array number scan experiments with the Z accelerator

Summary form only given, as follows. We are pursuing 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. 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. We are currently continuing the experiments with 30, 90, and 300 wire arrays. 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. In the new experiments axial diagnostics will be added. The X-ray radiated energy and power increase with wire number while the rise time and FWHM decrease. Analysis of the X-ray images suggests that the wires in the 50 wire array remain discreet and visible (not merged) until at least 20ns before pinch time while with 120 and higher wire number, wires appear merged at pinch times. Experimental results will be presented, analyzed and compared with numerical simulations.