Search

The implosion of a deuterium plasma toward an At wire was performed at the current amplitudes of 1.5-1.8 MA. The Al wire of I20 µm diameter and 4-5 cm length was placed on the top of the inner electrode. Pulses of XUV radiation and soft X-rays were detected at the maximum compression of the plasma focus column. They contained lines of Al VI - Al XIII ions. The presence of the Al wire on the axis of plasma focus column caused a decrease in the hard X-ray production and neutron yield to about 30-50%. The neutron pulse was characterized by the FWHM ≈ 200 ns and the yield up to 5×10[sup 10]. The maximum of the neutron production occurred up to 200 ns later than the maximum of the soft X-rays. [ABSTRACT FROM AUTHOR]

The results of the study of the Z-pinch and plasma-focus plasmas at presence of the axial C, Al, or Cu wires of sufficient high diameter are discused in this paper. The wire was positioned on the top of the inner electrode of the PF 1000 plasma focus (1.8 MA, IPPLM Warsaw), or at the axis with or without the tungsten or alumine wire array load at the S-300 facility (3 MA, RRC Kurchatov Institute, Moscow), and at the axis of the small Z-pinch Z-150 (50 kA, CTU Prague). The plasma corona around the wire was generated both by the current going through the wires and by the implosion of the wire array or of the current sheath. The experiments showed interesting results often observed in some shots of Z-pinch type discharges — existence of helical structures, two relatively long and stable pinch phases, oscillation of pinch diameter, and back return of the plasma exploding from the pinch. All these observed phenomena can be evolved by spontaneous self-generation and transformation of the axial magnetic field in the pinch during the plasma implosion and explosion. A configuration of axial and azimuthal magnetic field confines the plasma and later transforms or dissipates during a few tens or hundreds ns. A fast transformation of internal magnetic fields can induce a sufficiently high electric field for generation of keV panicles and radiation. [ABSTRACT FROM AUTHOR]

The ablation efficiency of organic polymers (polymethylmethacrylate - PMMA, polytetrafluoroethylene PTFE, polyethyleneterephtalate - PET, and polyimide - PI) and elemental solids (aluminum and silicon) by single pulses of extreme ultraviolet (XUV) radiation emitted from Z-pinch, plasma-focus, and laser-produced plasmas was investigated. The ablation characteristics measured for these plasma-based sources will be compared with those obtained for irradiation of samples with XUV radiation generated by a free-electron laser (FEL). The Z-pinch was driven by the S-300 pulsed-power machine (Kurchatov lnstitute, Moscow) and the plasma focus was realized in the PF-1000 machine (Institute of Plasma Physics and Laser Microfusion, Warsaw). Higher temperature plasma than with the discharge plasmas was obtained by focusing the near-infrared (fundamental frequency) beam from the PALS high-power iodine laser system (Czech Academy of Sciences, Prague) on the surface of a metallic slab target or into single- and double-gas-puff target placed in a vacuum interaction chamber. Much softer (λ = 86 nm), but monochromatic and more intense, radiation is provided in many (repetition rate= 1 Hz) short pulses by the SASE-FEL at the Tesla Test Facility (DESY-HASYLAB, Hamburg). The role of nonthermal processes in XUV ablation will be evaluated. Mechanisms based on the nonthermal processes will be proposed. [ABSTRACT FROM AUTHOR]