Design and performance of the Z magnetically-insulated transmission lines
The authors have designed and tested a 10 nH, 1.5 m radius vacuum section for the Z accelerator. The vacuum section consists of four vacuum flares, four conical 1.3 m radius magnetically-insulated transmission lines (MITLs), a 7.6 cm radius 12-post double-post-hole convolute which connects the four outer MITLs in parallel, and a 5 cm long inner MITL which connects the output of the convolute to a z-pinch load. The authors have demonstrated they can deliver a 100 ns rise-time 20 MA current pulse to the baseline z-pinch load. They can reproduce the peak MITL current to within /spl plusmn/1.6%. Power-flow measurements indicate the vacuum section performs as expected until peak current. Afterward, measurements and simulation results diverge.
Efficient x‐ray production from ultrafast gas‐puff Z pinches
The Proto‐II accelerator has been used to implode krypton and xenon annular gas puffs. A significant fraction of the machine electrical energy was converted first to plasma kinetic energy and then to x rays when the plasma pinched on axis. Quantitative measurements using time‐resolved bolometers have shown as much as 10% of the total radiation yield near 1 keV in Xe and 2 keV in Kr. We have compared this radiation yield to the predictions from one‐dimensional magnetohydrodynamic code calculations. The implosions were also observed with both time‐integrated pinhole cameras and spectrographs. No hard x‐ray (E>10 keV) output was observed.
Time and space resolved vacuum‐ultraviolet spectroscopy of an argon gas‐puff Z pinch
Time and radially resolved vacuum‐ultraviolet spectra from an argon gas‐puff Z pinch have been obtained using a grazing incidence spectrometer with gated microchannel plates curved to the Rowland circle. Most of the 50–300‐A radiation is emitted from a dense core (r≊0.4 mm, ne≳1019 cm−3, Te≊150 eV) which forms when the plasma assembles on the axis.