Dense Z-pinch research at the Nevada Terawatt Facility

Summary form only given, as follows. A high-repetition-rate, 2-terawatt Z-pinch (HDZP-II from LANL: 2 MV, 1 Mg 100 ns, 200 kJ, 1.9 ohm) has been reassembled to investigate the early-time evolution of a current-driven wire, the plasma turbulence around and between wires, the acceleration of a plasma current sheet by a magnetic field, and the suppression or reduction of plasma instabilities. The heating, expansion, and dynamics of wires driven by current prepulses similar to those at SNL-Z is being examined first. Optical, laser, and radiographic measurements of prepulse-driven exploding wires will be compared with the modeling results of Reisman et al. (LLNL). SNL-Z wires are exploded by an independent pulse generator (100 kV, 2 kA, 50 ns). Plasma self-emission, laser-schlieren, laser-absorption, and interferometric images (10 micron, 0.1 ns resolution) are obtained with streak cameras (S-l and S-20) and an Nd:glass laser (30 ns, 1064 or 532 nm). Multiframe point-projection radiography (few-micron, sub-ns resolution) is acheived by driving several X-pinch backlighters with HDZP-II. In addition, laser-induced-fluorescence imaging and X-ray absorption spectroscopy are being developed for this prepulse experiment, while laser polarimetry and collective Thomson scattering, and a suite of X-ray diagnostics, are being developed for future high-current experiments.