Exploding wire loads have been used for several years to generate a hot dense plasma. For a generator with a rise time of tens of nsec and an impedance of 1 Ω or less, the inductance of the wire load and the tendency of current to flow outside the wire limits the energy that can be transferred to the wire. An array of several wires has now been used to lower the inductance and improve the energy transfer.

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The Pithon pulsed electron beam accelerator was used to implode an argon plasma at 4 TW. The plasma was prepared by microwave preionization of an annular column of gas injected between the output electrodes of the pulser. The electrodynamic behavior implied that most of the gas was involved in the pinch. The plasma conditions were inferred from hydrogenlike and heliumlike x-ray emission spectra. Final pinch dimensions were determined from x-ray pinhole photographs and laser shadowgraphs.

Single-wire Fe spectra collected from two different exploded-wire generators (Gamble II and Owl II) were analyzed to determined the ionization stages produced in the plasmas. The temperature for the hot-plasma pinches for both generators was 1.4±0.2 keV at which an abundance of Fe XXIV transitions is produced. The Fe K spectra from exploded wires are basically similar to those produced in the pinched plasma generated randomly in the vacuum spark; however, the exploded wires have lower plasma temperatures than the hottest pinches produced in the vacuum spark. A detailed interpretation of the Fe L spectra formed in the exploded wires permitted line and ionization stage identifications in the 7–12-Å region. Such spectroscopic data is useful for analysis of complex Fe spectra generated in multitemperature plasma devices like Tokamaks.

Plasma erosion switches have been fielded on the PITHON generator during imploding plasma experiments. Theta pinch plasma guns were used to inject carbon plasmas of densities in the range of 1012–1014 cm3 between the electrodes of the vacuum power feed region, upstream from an imploding plasma load. Current monitors indicated that the erosion switches carried substantial current early in time, diverting it from the load. Late in the pulse the erosion switches opened, transferring the current to an imploding plasma with the effect of sharpening the current rise time at the load. Associated withthe sharper rise time was an improvement in the quality of the plasma implosions. The results of varying the density and total number of particles in the plasma of the switches are presented with regard to the effect on the current along the vacuum feed and on the behavior of vacuum flowing electrons.