Computer Modeling of Plasma Flow Switches-high Current Switching on Procyon
Computer Modeling of Plasma Flow Switches-high Current Switching on Procyon

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Published: 1993

Total Pages: 13

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Procyon is a high explosive driven pulsed power system designed to drive plasma z-pinch experiments to the 1-MJ level. Details of this system are provided elsewhere in these proceedings. The final switching stage of the Procyon system is a plasma flow switch (PFS). Our most recent experiment (April 29, 1993) included a full power test of the PFS designed for the Procyon system. In this test the Mark IX explosively driven generator delivered 22 MA of current to the storage inductor. The slight flux compression that occurs in the explosively formed fuse (EFF) opening switch increased this current to 24.5 MA. The EFF then opened and switched 16.5 MA to the PFS. The PFS switched 15.5 MA to the load region (the slot that will contain an imploding foil liner in future experiments) with a 10-90 rise time of 500 ns. In this present paper we discuss the computer modeling we have done on this Procyon plasma flow switch. In the next section we discuss the design of the Procyon switch and preshot calculations. Although the April 1993 experiment was quite successful there were significant surprizes in the performance of the PFS. In the last sections of this paper we discuss the work we have done in understanding the results of this experiment and the conclusions that we have reached to date.

Plasma and Electrical Diagnostics for Procyon Experiments
Plasma and Electrical Diagnostics for Procyon Experiments

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Published: 1991

Total Pages: 5

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The aim of the Trailmaster series of experiments is to generate an intense source of soft x-rays by imploding a thin (2000 Å) aluminum cylinder. The present scheme incorporates a plasma flow switch for the final pulse shaping and requires careful diagnostic analysis. The emphasis of this work is to transfer the energy to the load area and to understand the dynamics of the plasma flow switch. The experiments are carried out at LANL in two facilities. Laboratory experiments that answer questions about the details of the plasma flow switch are done on the 1.5-MJ Pegasus capacitor bank. The higher energy experiments (Procyon series) utilize explosive pulsed power systems and are conducted at the Ancho Canyon firing site. It is the latter set of experiments that will eventually supply an x-ray radiation source at the megajoule level. At the present time, the emphasis of the Procyon experiments is to deliver energy from the generator to the plasma flow switch and the load area. The details of these experiments are given in other papers at this conference. In order to characterize these experiments one needs to diagnose the driver performance and the dynamics of the plasma and power flow in the plasma flow switch region. The difficulty of experiments in which high current high voltage, and high explosive are combined, leads to severe problems. Many of the diagnostics are unique and untested. Since only a limited number of experiments are done during a year, the effort is to maximize the information per shot. The aim in this report is to present some of the diagnostic techniques used in the adverse Trailmaster environment. 8 refs., 10 figs.

Procyon Experiments Utilizing Foil-fuse Opening Switches
Procyon Experiments Utilizing Foil-fuse Opening Switches

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Published: 1991

Total Pages: 5

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The Los Alamos National Laboratory has applied the explosive magnetic flux compression generator (FCG) technology to the high-energy foil-implosion project, Trailmaster, to reach energy levels unattainable by other methods under current budget constraints. A required component for FCG systems is a power-conditioning stage that matches the slow risetime of the energy source with the fast-risetime requirements of the foil-implosion load. Currently, the Trailmaster concept is based on a two-step process of combining an intermediate power compression stage with a plasma flow switch (PFS) that will deliver energy to an imploding foil on the order of 100 ns. The intermediate power compression stage, which is the main emphasis of this report, consists of an energy storage inductor loaded by the FCG (the energy sauce) and an associated opening and closing switch. In our Procyon testing series, a subtask of the Trailmaster project, we have explored two approaches for opening and closing switches. One uses an explosive opening switch (EFF) and a detonator-initiated closing switch, the topic of another paper at this conference, and the other a resistive fuse opening switch a surface tracking closing switch (STS), the subject of this presentation. This latter concept was successfully tested last summer with a complete plasma flow switch assembly except the dynamic implosion foil was replaced by a rigid passive inductive load. We present data on the performance of the fuse opening switch, the surface tracking closing switch, and the plasma flow switch. 7 refs., 9 figs.

Procyon High Explosive Pulsed Power Experiments
Procyon High Explosive Pulsed Power Experiments

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Published: 1996

Total Pages: 13

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Procyon is a two-stage explosive pulsed-power system, consisting of a MK-IX helical generator and an explosively formed fuse (EFF) opening switch. A complete assembly including load and diagnostics is shown. The system was originally developed for the purpose of powering plasma z-pinch experiments and, in its original concept, was coupled to the plasma z-pinch load through a third pulsed power stage, a plasma flow switch (PFS). The authors have performed plasma z-pinch experiments both with and without a PFS, and they have now conducted the first heavy liner experiment. In this paper, they will summarize the results obtained to date with the system, and briefly discuss future applications.

Modeling of Plasma Flow Switches at Low, Intermediate and High Energies
Modeling of Plasma Flow Switches at Low, Intermediate and High Energies

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Published: 1992

Total Pages: 9

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Inductively stored pulsed power technology has been used over the past thirty years to produce multi-megaamp currents to implode low inductance loads and produce x-radiation. Because of the large difference in timescales for the delivery of magnetic energy to the load and the desire for high power x-radiation output (short timescale for the implosion), most inductively stored systems require at least one opening switch. The design and understanding of fast, efficient opening switches for multi-megaamp systems represents a long standing problem in pulsed power research. The Los Alamos Foil Implosion Project uses inductively stored magnetic energy to implode thin metallic liners. A plasma flow switch (PFS) has been investigated as the final pulse shaping step for this systems. The PFS consists of a wire array and a barrier foil located upstream from the load region. Several stages can be identified in the performance of the plasma flow switch. These are: (1) the vaporization of the wire array; (2) the assembly of the initiated plasma on tie barrier foil to form the switch plasma; (3) the motion of the switch plasma down the coaxial barrel; and (4) current switching to the load (the actual switching stage). The fourth stage affects the switch's efficiency, as well as the quality of the load implosion. Instabilities may develop during any of these four stages, and their presence may seriously degrade the structure of the switch plasma. Two primary criteria may be used to characterize good switching. The first is switching efficiency. A second criterion is transferred to the load during or after switching. This paper summarizes the computational design of the PFS experiments carried out on Pegasus 1. We conclude by considering the implications of these results for the design of a PFS for the higher energy regime (Procyon) regime.

Procyon: 18-MJ, 2-[mu] Pulsed Power System
Procyon: 18-MJ, 2-[mu] Pulsed Power System

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Published: 2006

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The Procyon high explosive pulsed power (HEPP) system was designed to drive plasma z-pinch experiments that produce Megajoule soft x-ray pulses when the plasma stagnates on axis. In the proceedings of the Ninth IEEE Pulsed Power Conference, we published results from system development tests. At this time, we have fielded seven tests in which the focus was on either vacuum switching or load physics. Four of the tests concentrated on the performance of a Plasma Flow Switch (PFS) which employed a 1/r mass distribution in the PFS barrel. Of the four tests, two had dummy loads and one had an implosion load. In addition, one of the tests broke down near the vacuum dielectric interface, and the result demonstrated what Procyon could deliver to an 18 nH load. We will summarize PFS results and the 18 nH test which is pertinent to upcoming solid/liquid liner experiments. On our other three tests, we eliminated the PFS switching and powered the z-pinch directly with the HEPP system. From the best of these direct drive tests we obtained 1.5 MJ of radiation in a 250 ns pulse, our best radiation pulse to date. We will also summarize direct drive test results. More details are given in other papers in this conference for both the PFS and direct drive experiments, and an updated analysis of our opening switch performed is also included. The remainder of this paper describes the parameters and capabilities of our system, and we will use the data from several experiments to provide more precise information than previously available.