Browsing by Author "Valenzuela, Julio"

Now showing 1 - 3 of 3
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    Measurements of Neutrons Created in a Staged Z-Pinch With Krypton Liner and Deuterium Target at a 1-MA Pulsed Power Generator
    (2023) Ruskov, Emil; Rahman, Hafiz U.; Conti, Fabio; Valenzuela, Julio; Aybar, Nicholas; Beg, Farhat N.
    Gas-puff fast Z-pinches are of considerable interest as a neutron source that can be operated in a repeatable mode and which may lead to a magneto-inertial fusion energy source. In our experiments on the 1-MA pulsed power generator Zebra a krypton gas shell was imploded to compress a central deuterium gas column. An external axial magnetic field B-z = 0.5 - 3.0 kG was used to stabilize the pinch against magneto Rayleigh-Taylor instabilities. A consistent neutron yield of (0.83 +/- 0.19) x 10(10) was measured with a silver activation detector with B-z >= 0.5 kG. The neutron emission isotropy was assessed with three neutron time of flight (nTOF) detectors.
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    Shock interactions between plasma jets from conical wire array Z-pinches and laser-produced plasma plume
    (2022) Izquierdo, Luisa; Veloso, Felipe; Valenzuela, Julio; Escalona, Miguel; Oportus, Diego; Favre, Mario
    The interaction of a supersonic plasma jet outflow with a background laser-produced plasma plume is experimentally studied. The aim of these studies is to provide an experimental platform to study jet-ambient interactions in an environment relevant to high energy density physics scenarios. The jet outflow is produced by a conical wire array Z-pinch composed of 16 aluminum wires (40 mu m diameter each) acting as load of the Llampudken generator (-400kA, -350 ns). The laser plasma plume is produced by focusing a 2 x 1010 W/cm2 laser pulse onto an aluminum target. Our experimental results show that in the absence of laser plasma plume, there is no significant photoionized plasma from the target that interacts with the jet outflow. On the contrary, when combining both plasma sources, a new structure appears at the interaction region. The thickness of this structure is of the order of the inter-particle ion-ion mean free path, which was calculated for a wide range of parameters for each plasma. These results indicate the presence of a collisional shock layer created after the interaction. Further details and potential applications are shown and discussed.
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    X-ray emission from copper X-pinches driven at a current rate of similar to 1kA/ns
    (ELSEVIER, 2021) Vescovi, Milenko; Veloso, Felipe; Valenzuela, Julio; Favre, Mario
    A characterization of Cu X-pinches experiments driven at current rates similar to 1kA/ns is presented. The emission of two bursts of X-rays associated with hot-spot formation and electron beam-target mechanism are identified. The first burst, associated with the central hot-spot, appears consistently at currents in the range (154 +/- 20) kA, with time correlated noticiable dips in the current derivative signal, which indicate sudden changes in load impedance. This first burst emits photons pulses of similar to 1-2 ns width and with source sizes ranging between 50 and 150 mu m with emission in the 2-5 keV energy range combined with photons in the similar to 8-9 keV range. The second burst, associated with electron beam-target mechanism, emits longer pulses of tens of nanoseconds, with source sizes larger than similar to 0.75 mm and emission concentrated in energies >5 keV, reaching up to 9 keV or more. Spectroscopic data shows the presence of K-shell line emissions of Cu XXVII and Cu XXVIII, which combined with PrismSpect simulations indicate a electron temperature of similar to 850 eV with an ion density of 10(22) cm(-3). Further details and analysis of the X-pinch plasma and its possible applications are presented and discussed.