Axial and temporal gradients in Mo wire array Z pinches

Three nested molybdenum wire arrays with initial outer diameters of 45, 50, and 55 mm were imploded by the ∼20MA, 90 ns rise-time current pulse of Sandia’s Z accelerator. The implosions generated Mo plasmas with ≈10% of the array’s initial mass reaching Ne-like and nearby ionization stages. These ions emitted 2–4 keV L-shell x rays with radiative powers approaching 10 TW. Mo L-shell spectra with axial and temporal resolution were captured and have been analyzed using a collisional-radiative model. The measured spectra indicate significant axial variation in the electron density, which increases from a few times 1020cm−3 at the cathode up to ∼3×1021cm−3 near the middle of the 20 mm plasma column (8 mm from the anode). Time-resolved spectra indicate that the peak electron density is reached before the peak of the L-shell emission and decreases with time, while the electron temperature remains within 10% of 1.7 keV over the 20–30 ns L-shell radiation pulse. Finally, while the total yield, peak total power, a...