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Sample records for high-power aluminum z-pinch

  1. Experimental astrophysics with high power lasers and Z pinches

    SciTech Connect

    Remington, B A; Drake, R P; Ryutov, D D

    2004-12-10

    With the advent of high energy density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, mm-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors; equations of state relevant to planetary interiors; strong shock driven nonlinear hydrodynamics and radiative dynamics, relevant to supernova explosions and subsequent evolution; protostellar jets and high Mach-number flows; radiatively driven molecular clouds and nonlinear photoevaporation front dynamics; and photoionized plasmas relevant to accretion disks around compact objects, such as black holes and neutron stars.

  2. Wire-number effects on high-power annular z-pinches and some characteristics at high wire number

    SciTech Connect

    SANFORD,THOMAS W. L.

    2000-05-23

    Characteristics of annular wire-array z-pinches as a function of wire number and at high wire number are reviewed. The data, taken primarily using aluminum wires on Saturn are comprehensive. The experiments have provided important insights into the features of wire-array dynamics critical for high x-ray power generation, and have initiated a renaissance in z-pinches when high numbers of wires are used. In this regime, for example, radiation environments characteristic of those encountered during the early pulses required for indirect-drive ICF ignition on the NIF have been produced in hohlraums driven by x-rays from a z-pinch, and are commented on here.

  3. Implosion characteristics and applications of combined tungsten-aluminum Z-pinch planar arrays

    NASA Astrophysics Data System (ADS)

    Osborne, G. C.; Kantsyrev, V. L.; Esaulov, A. A.; Safronova, A. S.; Weller, M. E.; Shrestha, I.; Williamson, K. M.; Shlyaptseva, V. V.

    2013-12-01

    An exploration of the implosion properties and X-ray radiation pulses from tungsten-based planar wire array Z-pinch experiments is presented, with an emphasis on loads mixed with aluminum. These experiments were carried out on Zebra, the 1.0 MA pulse power generator at the Nevada Terawatt Facility. A suite of diagnostics was used to study these plasmas, including X-ray and EUV Si diodes, optical imaging, laser shadowgraphy, and time-gated and time-integrated X-ray pinhole imagers and spectrometers. Specifically, loads with relatively large inter-wire gaps where tungsten is placed in the center of a planar configuration composed primarily of aluminum showed unusual characteristics. These loads are shown to generate a "bubbling" effect in which plasma from the ablation of outer aluminum wires is temporarily hindered from converging at the center of the array where the tungsten wire is located. Reproduction of these experiments with variations to load geometry, materials, and mass distribution are also presented and discussed in an attempt to better understand the phenomenon. In addition, a theoretical model has also been applied to better understand the dynamics of the implosions of these loads. Applications of this effect to radiation pulse shaping, particularly with multi-planar arrays, are also discussed.

  4. X-ray absorption spectroscopy of aluminum z-pinch plasma with tungsten backlighter planar wire array source.

    PubMed

    Osborne, G C; Kantsyrev, V L; Safronova, A S; Esaulov, A A; Weller, M E; Shrestha, I; Shlyaptseva, V V; Ouart, N D

    2012-10-01

    Absorption features from K-shell aluminum z-pinch plasmas have recently been studied on Zebra, the 1.7 MA pulse power generator at the Nevada Terawatt Facility. In particular, tungsten plasma has been used as a semi-backlighter source in the generation of aluminum K-shell absorption spectra by placing a single Al wire at or near the end of a single planar W array. All spectroscopic experimental results were recorded using a time-integrated, spatially resolved convex potassium hydrogen phthalate (KAP) crystal spectrometer. Other diagnostics used to study these plasmas included x-ray detectors, optical imaging, laser shadowgraphy, and time-gated and time-integrated x-ray pinhole imagers. Through comparisons with previous publications, Al K-shell absorption lines are shown to be from much lower electron temperature (∼10-40 eV) plasmas than emission spectra (∼350-500 eV).

  5. Characteristics of implosion and radiation for aluminum planar wire array z-pinch at 1.5 MA

    SciTech Connect

    Wang Liangping; Wu Jian; Li Mo; Han Juanjuan; Guo Ning; Wu Gang; Qiu Aici

    2012-12-15

    Planar wire arrays Z pinches were carried out on Qiangguang generator (1.5 MA, 100 ns). Loads with varied row widths (6-24 mm) and wire numbers (10-34) were employed in the experiments. The implosion dynamics of planar wire arrays has been studied. Meanwhile, the changes of the implosion time, radiation yield and power with array mass, inter-wire gap, and array width were investigated. The images of a soft X-ray camera exhibit that the trailing mass, precursor column, and R-T instability exist during the implosion phase, and when m = 0 maybe accompanied with m = 1, instability will rapidly develop after stagnation. The implosion trajectories show that loads will implode by the snowplow mode and about 50% of total initial array mass will participate in the final implosion. The maximum total X-ray energy is 22 kJ with a power of 630 GW, while the maximum K-shell yield is 3.9 kJ with a power of 158 GW. Experiments with different planar wire arrays show that the value of m{sub P}D{sub 0}{sup 2} (the product of line mass and squared width) is the critical factor which affects the implosion time and the X-ray products of the wire arrays. The optimum value of m{sub P}D{sub 0}{sup 2} should be in the range of 200-400 {mu}gcm and the inter-wire gap should be less than 1 mm.

  6. Z-Pinch Fusion Propulsion

    NASA Technical Reports Server (NTRS)

    Miernik, Janie

    2011-01-01

    Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Shorter trips are better for humans in the harmful radiation environment of deep space. Nuclear propulsion and power plants can enable high Ispand payload mass fractions because they require less fuel mass. Fusion energy research has characterized the Z-Pinch dense plasma focus method. (1) Lightning is form of pinched plasma electrical discharge phenomena. (2) Wire array Z-Pinch experiments are commonly studied and nuclear power plant configurations have been proposed. (3) Used in the field of Nuclear Weapons Effects (NWE) testing in the defense industry, nuclear weapon x-rays are simulated through Z-Pinch phenomena.

  7. Z-Pinch Discharge in Laser Produced Plasma

    SciTech Connect

    Sterling, E.; Lunney, J. G.

    2010-10-08

    A fast coaxial electrical discharge, with relatively low current, was used to produce a Z-pinch effect in a laser produced aluminum plasma. The ion flux in the laser plasma was monitored with a Langmuir ion probe. The line density in the plasma column was controlled by using an aperture to select the portion of the laser plasma which enters the discharge cell. The Z-pinch dynamics were recorded using time-resolved imaging of the visible self-emission; the plasma was pinched to about one-third of the initial radius. Both the laser and Z-pinch plasmas were diagnosed using time-and space-resolved spectroscopy; substantial heating was observed. The measured behaviour of the pinch was compared with predictions of the slug model.

  8. Z-Pinch Fusion for Energy Applications

    SciTech Connect

    SPIELMAN,RICK B.

    2000-01-01

    Z pinches, the oldest fusion concept, have recently been revisited in light of significant advances in the fields of plasma physics and pulsed power engineering. The possibility exists for z-pinch fusion to play a role in commercial energy applications. We report on work to develop z-pinch fusion concepts, the result of an extensive literature search, and the output for a congressionally-mandated workshop on fusion energy held in Snowmass, Co July 11-23,1999.

  9. The bumpy Z-pinch

    NASA Astrophysics Data System (ADS)

    Jensen, T. H.; Chu, M. S.

    1981-06-01

    The 'bumpy Z-pinch' is a magnetic configuration with potential usefulness for fusion reactors. A conceptually simple version of the configuration is axisymmetric. It contains regions of closed and open field lines. In the region of closed field lines, the field line topology is much like that of a tokamak; these regions link the region of open field lines around the axis of symmetry. Assuming that the plasma spontaneously maintains an equilibrium as described by Taylor (1974), it is possible to maintain indefinitely the regions of closed field lines by driving an axial current through the plasma in the region of open field lines. The ratio between the total axial driven current and the total poloidal current in each of the tokamak-like regions can, in principle, be made arbitrarily small, which means that the load impedance can be arbitrarily large. In addition, the configuration has the inherent virtue similar to that of the spheromak that the tokamak-like part of the plasma does not link any material coils.

  10. The Physics of Fast Z Pinches

    SciTech Connect

    RYUTOV,D.D.; DERZON,MARK S.; MATZEN,M. KEITH

    1999-10-25

    The spectacular progress made during the last few years in reaching high energy densities in fast implosions of annular current sheaths (fast Z pinches) opens new possibilities for a broad spectrum of experiments, from x-ray generation to controlled thermonuclear fusion and astrophysics. Presently Z pinches are the most intense laboratory X ray sources (1.8 MJ in 5 ns from a volume 2 mm in diameter and 2 cm tall). Powers in excess of 200 TW have been obtained. This warrants summarizing the present knowledge of physics that governs the behavior of radiating current-carrying plasma in fast Z pinches. This survey covers essentially all aspects of the physics of fast Z pinches: initiation, instabilities of the early stage, magnetic Rayleigh-Taylor instability in the implosion phase, formation of a transient quasi-equilibrium near the stagnation point, and rebound. Considerable attention is paid to the analysis of hydrodynamic instabilities governing the implosion symmetry. Possible ways of mitigating these instabilities are discussed. Non-magnetohydrodynamic effects (anomalous resistivity, generation of particle beams, etc.) are summarized. Various applications of fast Z pinches are briefly described. Scaling laws governing development of more powerful Z pinches are presented. The survey contains 36 figures and more than 300 references.

  11. The physics of fast Z pinches

    SciTech Connect

    Ryutov, D.D.; Derzon, M.S.; Matzen, M.K.

    1998-07-01

    The spectacular progress made during the last few years in reaching high energy densities in fast implosions of annular current sheaths (fast Z pinches) opens new possibilities for a broad spectrum of experiments, from x-ray generation to controlled thermonuclear fusion and astrophysics. Presently Z pinches are the most intense laboratory X ray sources (1.8 MJ in 5 ns from a volume 2 mm in diameter and 2 cm tall). Powers in excess of 200 TW have been obtained. This warrants summarizes the present knowledge of physics that governs the behavior of radiating current-carrying plasma in fast Z-pinches. This survey covers essentially all aspects of the physics of fast Z pinches: initiation, instabilities of the early stage, magnetic Rayleigh-Taylor instability in the implosion phase, formation of a transient quasi-equilibrium near the stagnation point, and rebound. Considerable attention is paid to the analysis of hydrodynamic instabilities governing the implosion symmetry. Possible ways of mitigating these instabilities are discussed. Non-magnetohydrodynamic effects (anomalous resistivity, generation of particle beams, etc.) are summarized. Various applications of fast Z pinches are briefly described. Scaling laws governing development of more powerful Z pinches are presented. The survey contains 52 figures and nearly 300 references.

  12. Radiating Shock Properties in the Z-pinch Dynamic Hohlraum

    SciTech Connect

    Rochau, Gregory A.; Bailey, J. E.; Chandler, G.; Lemke, R.; Peterson, K.; Slutz, S.; Maron, Y.; Fisher, V.; Stambulchik, E.; MacFarlane, J.

    2009-09-10

    The Z-pinch dynamic hohlraum is a high-power x-ray source used for a variety of high energy-density physics applications including high temperature opacity measurements and inertial confinement fusion (ICF). The system consists of a tungsten wire-array Z pinch that implodes onto a low-density CH{sub 2} foam launching a radiating shock that heats the hohlraum to radiation temperatures >200 eV. The temperature and density evolution of this shock have been inferred through the measurement of time- and space-resolved line emission from Si atoms locally doped in the CH{sub 2} foam. The observed emission spectra are analyzed through comparison to collisional-radiative calculations that include a detailed treatment of line-shapes and the effect of non-local radiation on the atomic level populations. As a complement to the detailed spectral data, the radial and azimuthal distribution of the axially directed shock emission is recorded with time-gated x-ray pinhole images that provide information on the spatial profile of the shock conditions. Together with broadband x-ray power measurements, these data provide a comprehensive suite of information to determine the shock dynamics and associated energetics of the Z-pinch dynamic hohlraum.

  13. Spectroscopic study in Z-pinch discharge

    SciTech Connect

    Garamoon, A.A.; Saudy, A.H.; Shark, W.

    1995-12-31

    The temporal variation of the emitted line intensity has been investigated, and thus an important information about the dynamic ionization stages in the Z-pinch discharge has been studied. Also the electron temperature Te, has been deduced by using a spectroscopic technique.

  14. Axial Instability Growth in Tungsten Wire Array Z-Pinches

    NASA Astrophysics Data System (ADS)

    Cahill, Adam; Knapp, Patrick; Greenly, John; Pikuz, Sergei; Shelkovenko, Tania; Hammer, David

    2010-11-01

    The individual exploding wires in wire array z-pinches have been shown to suffer from axially non-uniformity beginning from the moment of plasma formation. This non-uniformity grows in amplitude and wavelength until it reaches what appears to be a material dependent wavelength at the time array implosion begins. Previous work by Knapp et al. [1] studied the temporal evolution of this instability in aluminum wire arrays. We have extended that work to include the evolution of tungsten wire array instabilities. Time gated laser shadowgraphy is used to track wavelength and amplitude over a series of shots to develop a record of the instability's growth. We attempt to identify array parameters which significantly contribute to the growth of this instability. [4pt] [1] Knapp, P. F., J. B. Greenly, P. A. Gourdain, C. L. Hoyt, M. R. Martin, S. A. Pikuz, C. E. Seyler, T. A. Shelkovenko, and D. A. Hammer. ``Growth and Saturation of the Axial Instability in Low Wire Number Wire Array Z Pinches.'' Physics of Plasmas 17 (2010). Web.

  15. Simulation of Wire-Array Z Pinches with ALEGRA

    NASA Astrophysics Data System (ADS)

    Chantrenne, Sophie; Bliss, David; Cochrane, Kyle; Coverdale, Christine; Deeney, Chris; Hall, Clint; Haill, Thomas; Jones, Brent; Lepell, Paul; Oliver, Bryan; Sinars, Daniel

    2006-10-01

    Wire-array z pinches provide the x-ray radiation drive for Inertial Confinement Fusion Experiments at Sandia National Laboratories. A physical understanding of the physics of wire-array z pinches is important in providing a future radiation source capable of driving high-yield fusion capsules. Modeling of wire-array implosions on the Z machine were performed using the 2-D radiation MHD code Alegra. These new calculations use more accurate initial conditions that are more representative of the experimental data, allowing us to model the implosion through stagnation, to avoid radiation collapse, and to generate a radiation pulse that compares well with data. Code predictions will be compared with tungsten & aluminum wire-array data from Z. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the U.S. Department of Energy under Contract No. DE-AC04- 94AL85000. a Ktech Corporation, 1300 Eubank Blvd. S.E., Albuquerque, NM 87123-3336

  16. Z pinches: the past, present, and future

    NASA Astrophysics Data System (ADS)

    Sweeney, M. A.; Yonas, G.

    1998-11-01

    Intense electron and light ion beam and z pinch research is based on pulsed power capabilities developed at the Atomic Weapons Establishment in the early 1960s to test the resistance of weapon components to radiation bursts by using short-duration bremsstrahlung sources. Research at Sandia and at the Kurchatov Institute in the 1970s led to an electron beam approach to inertial confinement fusion (ICF). The electron approach ended in 1979 when it was realized that the bremsstrahlung could significantly degrade the fuel compression. ICF research on a more promising approach, light ions, began in the late 1970s with the discovery, at Cornell, Sandia, and the Naval Research Laboratory, of efficient ways to produce intense beams of light ions. At the same time as emergence of the ion approach, z pinches that had produced copious keV x rays since the early 1970s were examined as a way to generate lower-voltage x rays to drive an ICF capsule. In this poster we review the research paths that led to these changes and predict what the future may hold for the z-pinch technology being pursued at Sandia.

  17. Fusion Propulsion Z-Pinch Engine Concept

    NASA Technical Reports Server (NTRS)

    Miernik, J.; Statham, G.; Fabisinski, L.; Maples, C. D.; Adams, R.; Polsgrove, T.; Fincher, S.; Cassibry, J.; Cortez, R.; Turner, M.; Percy, T.

    2011-01-01

    Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Due to the great distances between the planets of our solar system and the harmful radiation environment of interplanetary space, high specific impulse (Isp) propulsion in vehicles with high payload mass fractions must be developed to provide practical and safe vehicles for human spaceflight missions. The Z-Pinch dense plasma focus method is a Magneto-Inertial Fusion (MIF) approach that may potentially lead to a small, low cost fusion reactor/engine assembly1. Recent advancements in experimental and theoretical understanding of this concept suggest favorable scaling of fusion power output yield 2. The magnetic field resulting from the large current compresses the plasma to fusion conditions, and this process can be pulsed over short timescales (10(exp -6 sec). This type of plasma formation is widely used in the field of Nuclear Weapons Effects testing in the defense industry, as well as in fusion energy research. A Decade Module 2 (DM2), approx.500 KJ pulsed-power is coming to the RSA Aerophysics Lab managed by UAHuntsville in January, 2012. A Z-Pinch propulsion concept was designed for a vehicle based on a previous fusion vehicle study called "Human Outer Planet Exploration" (HOPE), which used Magnetized Target Fusion (MTF) 3 propulsion. The reference mission is the transport of crew and cargo to Mars and back, with a reusable vehicle.

  18. Fusion in a staged Z-pinch

    NASA Astrophysics Data System (ADS)

    Wessel, F. J.; Rahman, H. U.; Ney, P.; Valenzuela, J.; Beg, F.; McKee, E.; Darling, T.

    2016-03-01

    This paper is dedicated to Norman Rostoker, our (FJW and HUR) mentor and long-term collaborator, who will always be remembered for the incredible inspiration that he has provided us. Norman's illustrious career dealt with a broad range of fundamental-physics problems and we were fortunate to have worked with him on many important topics: intense-charged-particle beams, field-reversed configurations, and Z-pinches. Rostoker 's group at the University of CA, Irvine was well known for having implemented many refinements to the Z-pinch, that make it more stable, scalable, and efficient, including the development of: the gas-puff Z-pinch [1], which provides for the use of an expanded range of pinch-load materials; the gas-mixture Z-pinch [2], which enhances the pinch stability and increases its radiation efficiency; e-beam pre-ionization [3], which enhances the uniformity of the initial-breakdown process in a gas pinch; magnetic-flux-compression [4, 5], which allows for the amplification of an axial-magnetic field Bz; the Z-θ pinch [6], which predicts fusion in a pinch-on-fiber configuration; the Staged Z-pinch (SZP) [7], which allows for the amplification of the pinch self-magnetic field, Bθ , in addition to a Bz, and leads to a stable implosion and high-gain fusion [8, 9, 10]. This paper describes the physical basis for a magneto-inertial compression in a liner-on-target SZP [11]. Initially a high-atomic-number liner implodes under the action of the J →×B → , Lorentz Force. As the implosion becomes super Alfvénic, magnetosonic waves form, transporting current and magnetic field through the liner toward the interface of the low-atomic-number target. The target implosion remains subsonic with its surface bounded by a stable-shock front. Shock waves that pass into the target provide a source of target plasma pre-heat. At peak compression the assembly is compressed by liner inertia, with flux compression producing an intense-magnetic field near the target

  19. Chemically etched modulation in wire radius for wire array Z-pinch perturbation studies

    SciTech Connect

    Jones, B.; Deeney, C.; McKenney, J.L.; Garrity, J.E.; Lobley, D.K.; Martin, K.L.; Griego, A.E.; Ramacciotti, J.P.; Bland, S.N.; Lebedev, S.V.; Bott, S.C.; Ampleford, D.J.; Palmer, J.B.A.; Rapley, J.; Hall, G.

    2004-11-01

    A technique for manufacturing wires with imposed modulation in radius with axial wavelengths as short as 1 mm is presented. Extruded aluminum 5056 with 15 {mu}m diameter was masked and chemically etched to reduce the radius by {approx}20% in selected regions. Characterized by scanning electron microscopy, the modulation in radius is a step function with a {approx}10 {mu}m wide conical transition between thick and thin segments, with some pitting in etched regions. Techniques for mounting and aligning these wires in arrays for fast z-pinch experiments will be discussed. Axially mass-modulated wire arrays of this type will allow the study of seeded Rayleigh-Taylor instabilities in z pinches, corona formation, wire initiation with varying current density in the wire core, and correlation of perturbations between adjacent wires. This tool will support magnetohydrodynamics code validation in complex three-dimensional geometries, and perhaps x-ray pulse shaping.

  20. Progress in Z-pinch inertial fusion energy.

    SciTech Connect

    Weed, John Woodruff

    2010-03-01

    The goal of z-pinch inertial fusion energy (IFE) is to extend the single-shot z-pinch inertial confinement fusion (ICF) results on Z to a repetitive-shot z-pinch power plant concept for the economical production of electricity. Z produces up to 1.8 MJ of x-rays at powers as high as 230 TW. Recent target experiments on Z have demonstrated capsule implosion convergence ratios of 14-21 with a double-pinch driven target, and DD neutron yields up to 8x10exp10 with a dynamic hohlraum target. For z-pinch IFE, a power plant concept is discussed that uses high-yield IFE targets (3 GJ) with a low rep-rate per chamber (0.1 Hz). The concept includes a repetitive driver at 0.1 Hz, a Recyclable Transmission Line (RTL) to connect the driver to the target, high-yield targets, and a thick-liquid wall chamber. Recent funding by a U.S. Congressional initiative for $4M for FY04 is supporting research on RTLs, repetitive pulsed power drivers, shock mitigation, full RTL cycle planned experiments, high-yield IFE targets, and z-pinch power plant technologies. Recent results of research in all of these areas are discussed, and a Road Map for Z-Pinch IFE is presented.

  1. Z-Pinch Pulsed Plasma Propulsion Technology Development

    NASA Technical Reports Server (NTRS)

    Polsgrove, Tara; Adams, Robert B.; Fabisinski, Leo; Fincher, Sharon; Maples, C. Dauphne; Miernik, Janie; Percy, Tom; Statham, Geoff; Turner, Matt; Cassibry, Jason; Cortez, Ross; Santarius, John

    2010-01-01

    Fusion-based propulsion can enable fast interplanetary transportation. Magneto-inertial fusion (MIF) is an approach which has been shown to potentially lead to a low cost, small reactor for fusion break even. The Z-Pinch/dense plasma focus method is an MIF concept in which a column of gas is compressed to thermonuclear conditions by an axial current (I approximates 100 MA). Recent advancements in experiments and the theoretical understanding of this concept suggest favorable scaling of fusion power output yield as I(sup 4). This document presents a conceptual design of a Z-Pinch fusion propulsion system and a vehicle for human exploration. The purpose of this study is to apply Z-Pinch fusion principles to the design of a propulsion system for an interplanetary spacecraft. This study took four steps in service of that objective; these steps are identified below. 1. Z-Pinch Modeling and Analysis: There is a wealth of literature characterizing Z-Pinch physics and existing Z-Pinch physics models. In order to be useful in engineering analysis, simplified Z-Pinch fusion thermodynamic models are required to give propulsion engineers the quantity of plasma, plasma temperature, rate of expansion, etc. The study team developed these models in this study. 2. Propulsion Modeling and Analysis: While the Z-Pinch models characterize the fusion process itself, propulsion models calculate the parameters that characterize the propulsion system (thrust, specific impulse, etc.) The study team developed a Z-Pinch propulsion model and used it to determine the best values for pulse rate, amount of propellant per pulse, and mixture ratio of the D-T and liner materials as well as the resulting thrust and specific impulse of the system. 3. Mission Analysis: Several potential missions were studied. Trajectory analysis using data from the propulsion model was used to determine the duration of the propulsion burns, the amount of propellant expended to complete each mission considered. 4

  2. A Z-Pinch Driven Fusion Reactor Concept

    NASA Astrophysics Data System (ADS)

    Derzon, Mark; Rochau, Gregory; Spielman, Rick; Slutz, Stephen; Rochau, G. E.; Peterson, R. R.; Peterson, P. F.

    1999-11-01

    Recent z-pinch target physics progress has encouraged us to consider how a power reactor could be configured based on a fast z-pinch driver. Initial cost estimates show that recyclable transmission lines (RTLs) are economically viable. Providing 'standoff' between the primary power supply and the target, which is what disposable RTLs provide, has historically been the main obstacle to the consideration of pinches as fusion drivers. We will be introducing basic reactor scaling in terms of shot rate, yield, tritium breeding and neutron flux, etc. This concept has advantages in that z-pinches provide a robust mechanical environment, as well as a chamber which does not require low-pressure pumping between shots and the wall lifetime is expected to be limited factors other than neutron damage. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

  3. Investigation of Metal Puff Z pinch Based on Multichannel Vacuum Arcs

    NASA Astrophysics Data System (ADS)

    Rousskikh, A. G.; Oreshkin, V. I.; Zhigalin, A. S.; Chaikovsky, S. A.; Baksht, R. B.; Mitrofanov, K. N.

    2015-11-01

    The performance of a metal double puff Z-pinch system has been studied experimentally. In this type of system, the outer and inner cylindrical shells were produced by ten plasma guns. Each gun initiates a vacuum arc operating between aluminum electrodes. The net current of the guns was 80 kA. The arc-produced plasma shells were compressed by using a 450-kA, 450-ns driver, and as a result, a plasma column 0.2 cm in diameter was formed. The power of the Al K-line radiation emitted by the plasma for 7 ns was 800 MW/cm.

  4. Polycrystalline diamond based detector for Z-pinch plasma diagnosis

    SciTech Connect

    Liu Linyue; Zhao Jizhen; Chen Liang; Ouyang Xiaoping; Wang Lan

    2010-08-15

    A detector setup based on polycrystalline chemical-vapor-deposition diamond film is developed with great characteristics: low dark current (lower than 60 pA within 3 V/{mu}m), fast pulsed response time (rise time: 2-3 ns), flat spectral response (3-5 keV), easy acquisition, low cost, and relative large sensitive area. The characterizing data on Qiangguang-I accelerator show that this detector can satisfy the practical requirements in Z-pinch plasma diagnosis very well, which offers a promising prototype for the x-ray detection in Z-pinch diagnosis.

  5. {alpha} Heating in a Stagnated Z-pinch

    SciTech Connect

    Appelbe, Brian; Chittenden, Jeremy

    2009-01-21

    A computational investigation of a scheme for magneto-inertial confinement fusion in a Z-pinch is carried out. In the scheme implosion of a deuterium-tritium fuel mass is preceded by formation of a hotspot containing warm, dense plasma on axis. The presence of the hotspot increases energy yield. Compression of the hotspot by the main fuel mass initiates thermonuclear burn. There is significant heating of the plasma by thermonuclear {alpha} particles which are confined by the strong magnetic field of the Z-pinch.

  6. Physics issues relevant during stagnation phase of the Z pinch

    NASA Astrophysics Data System (ADS)

    Yu, Edmund

    2006-10-01

    Wire-array Z pinches are the most powerful laboratory x-ray sources. However, the physics driving the stagnation phase, during which the pinch collapses on axis and subsequently radiates, remains somewhat mysterious. In particular the stagnated pinch resists undergoing radiative collapse, and the radiated energy is several times the kinetic energy of the imploding plasma. In recent years, a number of theories, as well as direct 3D numerical simulation, have been developed to address these phenomena. This work will highlight some of the physics issues relevant during this complicated phase of the Z pinch. Possibilities for future work will be discussed, and, with a little luck, performed.

  7. Thermonuclear fusion in a staged Z-Pinch

    NASA Astrophysics Data System (ADS)

    van Drie, Alan David

    2001-05-01

    The Staged Z-Pinch idea was born out of trying to understand the enhanced X-ray yield from shell onto target Z-Pinches I performed in the late 1980s as an undergraduate student at UCI [1]. The idea was further matured through later successes of multi-shell implosions demonstrated at UCI, the Ecole Polytechnique in France, and the Kurchatov Institute in Russia. The Staged Z-Pinch is based upon a hybrid of a Z-Z and Z- Θ Pinch, i.e., an outer Z-Pinch drives Z and Θ currents on a separate coaxial inner target, through compression of axial and azimuthal magnetic fields trapped between the two. These fields provide magnetic shear stabilization. The load configurations tested were: 4 cm dia. Kr hollow gas shell liner with a 1.7 cm dia. D2 hollow gas shell and solid D2 gas jet targets. It is experimentally and computationally observed, that the Kr liner achieves a spectrum of high charge states, which peels off and accelerates ahead of the bulk of the liner. As this Kr implodes onto the deuterium core, it compresses the axial and azimuthal magnetic fields trapped in the liner-target gap, driving the target as a Staged Z-Pinch. In addition, axial current is constantly transferring from the liner to the deuterium target, and eventually dominates over the staged z-pinching of the target and instead drives it as a Z-Pinch. Even without any initial axial Bz field both the peeling and implosion of the target appear RT stable. I call this type of load configuration a Peeled Pinch. For our Staged Z-Pinch experiments, I designed and assembled a mega-ampere, μ s-class pulsed-power driver [2]. This would drive the Kr liner at current levels of 1.2 MA with implosion times of about 150 ns. To study the pinch I developed and installed neutron, optical, and x-ray diagnostics. For neutrons this includes: Ag activation, bubble and TOF detectors. For optical this includes: a N2 laser schlieren and a streak camera diagnostics. For x-rays this includes: a pinhole camera, XRDS and PINs.

  8. Rotating plasma disks in dense Z-pinch experiments

    SciTech Connect

    Bennett, M. J. E-mail: s.lebedev@imperial.ac.uk; Lebedev, S. V. E-mail: s.lebedev@imperial.ac.uk; Suttle, L.; Burdiak, G.; Suzuki-Vidal, F.; Hare, J.; Swadling, G.; Patankar, S.; Bocchi, M.; Chittenden, J. P.; Smith, R.; Hall, G. N.; Frank, A.; Blackman, E.; Drake, R. P.; Ciardi, A.

    2014-12-15

    We present data from the first z-pinch experiments aiming to simulate aspects of accretion disk physics in the laboratory. Using off axis ablation flows from a wire array z-pinch we demonstrate the formation of a hollow disk structure that rotates at 60 kms{sup −1} for 150 ns. By analysing the Thomson scattered spectrum we make estimates for the ion and electron temperatures as T{sub i} ∼ 60 eV and ZT{sub e} ∼ 150 to 200 eV.

  9. 9th International Conference on Dense Z-Pinches

    SciTech Connect

    Bott-Suzuki, Simon

    2015-08-31

    DOE OFES supported the 9th International Conference on Z-Pinches (DZP 2014) held in Napa, CA in August 2014. Funds were used to support travel for several US students, and to disseminate information through the publication of a proceedings volume.

  10. MHD simulation studies of z-pinch shear flow stabilization

    NASA Astrophysics Data System (ADS)

    Paraschiv, I.; Bauer, B. S.; Sotnikov, V. I.; Makhin, V.; Siemon, R. E.

    2003-10-01

    The development of the m=0 instability in a z-pinch in the presence of sheared plasma flows is investigated with the aid of a two-dimensional magnetohydrodynamic (MHD) simulation code (MHRDR). The linear growth rates are compared to the results obtained by solving the ideal MHD linearized equations [1] and to the results obtained using a 3D hybrid simulation code [2]. The instability development is followed into the nonlinear regime where its growth and saturation are examined. [1] V.I. Sotnikov, I. Paraschiv, V. Makhin, B.S. Bauer, J.-N. Leboeuf, and J.M. Dawson, "Linear analysis of sheared flow stabilization of global magnetohydrodynamic instabilities based on the Hall fluid mode", Phys. Plasmas 9, 913 (2002). [2] V.I. Sotnikov, V. Makhin, B.S. Bauer, P. Hellinger, P. Travnicek, V. Fiala, J.-N. Leboeuf, "Hybrid Simulations of Current-Carrying Instabilities in Z-pinch Plasmas with Sheared Axial Flow", AIP Conference Proceedings, Volume 651, Dense Z-Pinches: 5th International Conference on Dense Z-Pinches, edited by J. Davis et al., page 396, June 2002.

  11. Z-pinch experiments on Saturn at 30 TW

    NASA Astrophysics Data System (ADS)

    Spielman, R. B.; Dukart, R. J.; Hanson, D. L.; Hammel, B. A.; Hsing, W. W.; Matzen, M. K.; Porter, J. L.

    We have recently completed the first gas-puff z-pinch on Saturn (32 TW, 1.4 MJ, 1.9 MV, 40-ns FWHM, and 0.11 ohm). These experiments used the most powerful driver to date for fast z-pinch experiments. Saturn, a 36 module accelerator, uses a double post-hole vacuum convolute to deliver the total machine current to the load. The 10-nH Saturn z-pinch diode is capable of delivering a peak current of 10.5 MA. We diagnosed the current using segmented Rogowski coils at the insulator, resistive shunts in the vacuum transmission lines, and B-dot loops and piezoelectric pressure gauges near the load. On most shots electrical losses in the vacuum convolute were minimal with nearly complete current delivery to the z-pinch load. We have conducted experiments with deuterium, neon, argon, krypton, and xenon gas puffs. A maximum total radiation yield of 505 + or - 25 kJ was obtained with xenon. The peak keV X-ray yields were 100 + or - 5 kJ for neon K-shell radiation, 30 + or - 4 kJ for krypton L-shell radiation, and 39 + or - 4 kJ for argon K-shell radiation.

  12. Z-pinch experiments on Saturn at 30 TW

    NASA Astrophysics Data System (ADS)

    Spielman, R. B.; Dukart, R. J.; Hanson, D. L.; Hammel, B. A.; Hsing, W. W.; Matzen, M. K.; Porter, J. L.

    1989-12-01

    We have recently completed the first gas-puff Z-pinch experiments on Saturn (32 TW, 1.4 MJ, 1.9 MV, 40-ns FWHM, and 0.11 Ω). These experiments used the most powerful driver to date for fast Z-pinch experiments. Saturn, a 36 module accelerator, uses a double post-hole vacuum convolute to deliver the total machine current to the load. The 10-nH Saturn Z-pinch diode is capable of delivering a peak current of 10.5 MA. We diagnosed the current using segmented Rogowski coils at the insulator, resistive shunts in the vacuum transmission lines, and B-dot loops and piezoelectric pressure gauges near the load. On most shots electrical losses in the vacuum convolute were minimal with nearly complete current delivery to the Z-pinch load. We have conducted experiments with deuterium, neon, argon, krypton, and xenon gas puffs. A maximum total radiation yield of 505+/-25 kJ was obtained with xenon. The peak keV x-ray yields were 100+/-5 kJ for neon L-shell radiation, 30+/-4 kJ for krypton l-shell radiation, and 39+/-4 kJ for argon K-shell radiation.

  13. Measurement and analysis of x-ray absorption in Al and MgF2 plasmas heated by Z-pinch radiation.

    SciTech Connect

    MacFarlane, Joseph John; Rochau, Gregory Alan; Bailey, James E.

    2005-06-01

    High-power Z pinches on Sandia National Laboratories Z facility can be used in a variety of experiments to radiatively heat samples placed some distance away from the Z-pinch plasma. In such experiments, the heating radiation spectrum is influenced by both the Z-pinch emission and the re-emission of radiation from the high-Z surfaces that make up the Z-pinch diode. To test the understanding of the amplitude and spectral distribution of the heating radiation, thin foils containing both Al and MgF{sub 2} were heated by a 100-130 TW Z pinch. The heating of these samples was studied through the ionization distribution in each material as measured by x-ray absorption spectra. The resulting plasma conditions are inferred from a least-squares comparison between the measured spectra and calculations of the Al and Mg 1s {yields} 2p absorption over a large range of temperatures and densities. These plasma conditions are then compared to radiation-hydrodynamics simulations of the sample dynamics and are found to agree within 1{sigma} to the best-fit conditions. This agreement indicates that both the driving radiation spectrum and the heating of the Al and MgF{sub 2} samples is understood within the accuracy of the spectroscopic method.

  14. Magnetic Field Measurements in Wire-Array Z-Pinches

    NASA Astrophysics Data System (ADS)

    Syed, Wasif; Hammer, David; Lipson, Michal

    2006-10-01

    Understanding the evolution of the magnetic field topology and magnitude in the high energy density plasmas produced by wire-array Z-pinches is of critical importance for their ultimate application to stockpile stewardship and inertial confinement fusion^1. A method to determine the magnetic field profile in megampere level wire-array Z-pinches with high spatial and temporal resolution is under development. An ideal method would be passive and non-perturbing, such as Faraday rotation of laser light. We are developing a method involving temporally-resolved Faraday rotation through a sensing waveguide placed in the vicinity of, and eventually in, a wire-array Z-pinch^2. We present measurements of the magnetic field outside of a wire-array, and progress on measurements within the array. Our ideal device is a ``thin film waveguide'' coupled to an optical fiber system. While these sensing devices may not survive for long in a dense Z-pinch, they may provide useful information for a significant fraction of the current pulse. We present preliminary theoretical and experimental results. 1. M. Keith Matzen, M. A. Sweeney, R. G. Adams et al., Phys. Plasmas 12, 055503 (2005). 2. W. Syed, D. A. Hammer, M. Lipson, R. B. van Dover, AIP Proceedings of the 6th International Conference on Dense Z-Pinches, University of Oxford, UK, July 25-28, 2005. *This research was sponsored by the National Nuclear Security Administration under the Stockpile Stewardship Academic Alliances program through DOE Cooperative Agreement DE-F03-02NA00057.

  15. Wire array z-pinch insights for high x-ray power generation

    SciTech Connect

    Sanford, T.W.L.; Mock, R.C.; Nash, T.J.

    1998-08-01

    The discovery that the use of very large numbers of wires enables high x-ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities on Saturn. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. X=ray measurement comparisons with analytic models and 2-D radiation-magnetohydrodynamic (RMHC) code simulations in the x-y and r-z planes provide confidence in the ability of the models and codes to predict future x-ray performance with very-large-number wire arrays.

  16. Resolving microstructures in Z pinches with intensity interferometry

    SciTech Connect

    Apruzese, J. P.; Kroupp, E.; Maron, Y.; Giuliani, J. L.; Thornhill, J. W.

    2014-03-15

    Nearly 60 years ago, Hanbury Brown and Twiss [R. Hanbury Brown and R. Q. Twiss, Nature 178, 1046 (1956)] succeeded in measuring the 30 nrad angular diameter of Sirius using a new type of interferometry that exploited the interference of photons independently emitted from different regions of the stellar disk. Its basis was the measurement of intensity correlations as a function of detector spacing, with no beam splitting or preservation of phase information needed. Applied to Z pinches, X pinches, or laser-produced plasmas, this method could potentially provide spatial resolution under one micron. A quantitative analysis based on the work of Purcell [E. M. Purcell, Nature 178, 1449 (1956)] reveals that obtaining adequate statistics from x-ray interferometry of a Z-pinch microstructure would require using the highest-current generators available. However, using visible light interferometry would reduce the needed photon count and could enable its use on sub-MA machines.

  17. Seeded perturbations in wire array z-pinches.

    SciTech Connect

    Robinson, Allen Conrad; Kantsyrev, Victor Leonidovich; Wunsch, Scott Edward; Oliver, Bryan Velten; Lebedev, Sergey V.; Safronova, Alla S.; Maxwell, J.; McKenney, John Lee; Ampleford, David J.; Rapley, J.; Bott, S. C.; Palmer, J. B. A.; Bland, Simon Nicholas; Jones, Brent Manley; Chittenden, Jeremy Paul; Garasi, Christopher Joseph; Hall, Gareth Neville; Mehlhorn, Thomas Alan; Deeney, Christopher

    2004-11-01

    The impact of 3D structure on wire array z-pinch dynamics is a topic of current interest, and has been studied by the controlled seeding of wire perturbations. First, Al wires were etched at Sandia, creating 20% radial perturbations with variable axial wavelength. Observations of magnetic bubble formation in the etched regions during experiments on the MAGPIE accelerator are discussed and compared to 3D MHD modeling. Second, thin NaF coatings of 1 mm axial extent were deposited on Al wires and fielded on the Zebra accelerator. Little or no axial transport of the NaF spectroscopic dopant was observed in spatially resolved K-shell spectra, which places constraints on particle diffusivity in dense z-pinch plasmas. Finally, technology development for seeding perturbations is discussed.

  18. Characterization of Z-Pinch Driven Hohlraum Radiation Sources*

    NASA Astrophysics Data System (ADS)

    Porter, J. L.; Chandler, G. A.; Deeney, C.; Fehl, D. L.; Noack, D. D.; Olson, R. E.; Ruggles, L. E.; Seaman, J. F.; Spielman, R. B.; Torres, J. A.; Vargas, M. F.; Bartlett, R. J.; Benage, J. F., Jr.; Idzorek, G. C.

    1996-11-01

    We have developed a z-pinch-driven soft x-ray radiation source that is near-Planckian in spectral shape and very uniform over spatial dimensions of several millimeters. We create this radiation source by surrounding a z-pinch implosion with a high-Z radiation case (a hohlraum). This experimental arrangement is referred to as the =B3vacuum hohlraum=B2 configuration. We have measured hohlraum temperatures of greater than 75 eV which last for 10=B9s of nanoseconds using the 7-MA Saturn accelerator. We will begin z-pinch experiments this fall using the 16-MA PBFA-Z accelerator. The PBFA-Z driver will be able to produce hohlraums with radiation temperatures well in excess of 100 eV. In this presentation we will describe measurements of the time history of the x-ray power, spectrum, and spatial uniformity of hohlraums produced using the Saturn accelerator. We will also present preliminary measurements of the radiation temperature of hohlraums created using the recently commissioned PBFA-Z accelerator. *This work supported by the U.S. Department of Energy under contract DE-AC04-94AL85000.

  19. The ZaP Flow Z-Pinch Project - Final Technical Report

    SciTech Connect

    Shumlak, Uri; Nelson, Brian A.

    2013-12-31

    The ZaP Flow Z-Pinch Project is a project to extend the performance of the flow Z-pinch experiment at the University of Washington to investigate and isolate the relevant physics of the stabilizing effect of plasma flow. Experimental plasmas have exhibited an enhanced stability under certain operating parameters which generate a flow state (axial flows in Z-pinches and VH mode in tokamaks). Flow has also been suggested as the stabilizing mechanism in astrophysical jets.

  20. Development of the Axial Instability in Low Wire Number Wire Array Z-Pinches

    SciTech Connect

    Knapp, P. F.; Bell, K. S.; Blesener, I. C.; Chalenski, D. A.; Douglass, J. D.; Greenly, J. B.; Martin, M. R.; McBride, R. D.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Kusse, B. R.; Hall, G. N.

    2009-01-21

    We are investigating the development of the axial instability, a modulation of the size of the coronal plasma that develops around each wire in wire-array Z-pinches. The modulation is a result of nonuniform ablation of material from the relatively cold wire core. It has long been known that the wavelength of this modulation is constant late in time and, since it is unique to different materials, it has come to be known as the fundamental mode. In these experiments we imaged individual wires with laser shadowgraphy early in time primarily in low wire number, large wire diameter aluminum arrays for ease of viewing. We Observe the development of this modulation from the time of initiation of coronal plasma, obtaining its dominant wavelength and amplitude growth as a function of time. We also studied the instability on coiled wires, which modify the wire ablation mechanism and completely suppress the fundamental mode[Hall2008]. time is discussed.

  1. Fast Z - Pinch Study in Russia and Related Problems

    NASA Astrophysics Data System (ADS)

    Grabovskii, E. V.

    2002-12-01

    The fast Z pinches are considered as a perspective source of powerful soft x-ray emission for the ICF pellet ignition. The physical phenomena which take place in process fast of Z-pinch implosion are under investigation in the TRINITI (Troisk), in the RSC Kurchatov Institute (KI, Moscow) and the HCEI (Tomsk). In the KI the possibility of terawatt electrical power transfer in small volume hohlraum during nanosecond time duration is studied. In the TRINITI the physics of multi wire arrays implosion, the rate of plasma production in current-driven wire arrays, the conversion of pulsed power energy into x-ray emission are studied. In the HCEI (Tomsk) the stability of double gas puff implosion and the influence of gas puff regime and current pulse duration on the implosion and emitted x-ray spectrum are under investigation. The HCEI develops the new components of pulse power multi spark switches and the generators of impulse currents (LTD) with duration of an energy supply less than 100 ns. As available way to get the pulsed power generator with multi tens megaampere current the joint team of scientists from the laboratories of the TRINITI, the Efremov Institute, RFNC VNIITF (Snezinsk) have developed the concept of the Baikal facility. The KI designs, creates and tests the plasma erosion switches for the module of the Baikal facility. The inductive storage, the systems of magnetic field compression and the explosive open switches are developed in the TRINITI and the Efremov Institute. The development of new design of the pulse power generators and physics of fast Z-pinch implosion aims to create next advanced generation of powerful driver for ICF.

  2. Z-Pinch fusion-based nuclear propulsion

    NASA Astrophysics Data System (ADS)

    Miernik, J.; Statham, G.; Fabisinski, L.; Maples, C. D.; Adams, R.; Polsgrove, T.; Fincher, S.; Cassibry, J.; Cortez, R.; Turner, M.; Percy, T.

    2013-02-01

    Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Due to the great distances between the planets of our solar system and the harmful radiation environment of interplanetary space, high specific impulse (Isp) propulsion in vehicles with high payload mass fractions must be developed to provide practical and safe vehicles for human space flight missions. The Z-Pinch dense plasma focus method is a Magneto-Inertial Fusion (MIF) approach that may potentially lead to a small, low cost fusion reactor/engine assembly [1]. Recent advancements in experimental and theoretical understanding of this concept suggest favorable scaling of fusion power output yield [2]. The magnetic field resulting from the large current compresses the plasma to fusion conditions, and this process can be pulsed over short timescales (10-6 s). This type of plasma formation is widely used in the field of Nuclear Weapons Effects testing in the defense industry, as well as in fusion energy research. A Z-Pinch propulsion concept was designed for a vehicle based on a previous fusion vehicle study called "Human Outer Planet Exploration" (HOPE), which used Magnetized Target Fusion (MTF) [3] propulsion. The reference mission is the transport of crew and cargo to Mars and back, with a reusable vehicle. The analysis of the Z-Pinch MIF propulsion system concludes that a 40-fold increase of Isp over chemical propulsion is predicted. An Isp of 19,436 s and thrust of 3812 N s/pulse, along with nearly doubling the predicted payload mass fraction, warrants further development of enabling technologies.

  3. Radiating Shock Measurements in the Z-Pinch Dynamic Hohlraum

    SciTech Connect

    Rochau, G. A.; Bailey, J. E.; Chandler, G. A.; Lemke, R. W.; Peterson, K. J.; Slutz, S. A.; Maron, Y.; Fisher, D. V.; Fisher, V. I.; Stambulchik, E.; Dunham, G. S.; MacFarlane, J. J.; Schroen, D. G.

    2008-03-28

    The Z-pinch dynamic hohlraum is an x-ray source for high energy-density physics studies that is heated by a radiating shock to radiation temperatures >200 eV. The time-dependent 300-400 eV electron temperature and 15-35 mg/cc density of this shock have been measured for the first time using space-resolved Si tracer spectroscopy. The shock x-ray emission is inferred from these measurements to exceed 50 TW, delivering >180 kJ to the hohlraum.

  4. High energy density Z-pinch plasmas using flow stabilization

    SciTech Connect

    Shumlak, U. Golingo, R. P. Nelson, B. A. Bowers, C. A. Doty, S. A. Forbes, E. G. Hughes, M. C. Kim, B. Knecht, S. D. Lambert, K. K. Lowrie, W. Ross, M. P. Weed, J. R.

    2014-12-15

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and

  5. Nonlinear Rayleigh-Taylor instabilities in fast Z pinches

    SciTech Connect

    Miles, Aaron R.

    2009-03-15

    A simplified analytic model is presented to describe the implosion of a plasma column by an azimuthal magnetic field of sufficient magnitude to drive a strong shock wave into the plasma. This model is employed together with buoyancy-drag-based models of nonlinear single-mode and turbulent multimode Rayleigh-Taylor growth to investigate the mixing process in such fast Z pinches. These models give predictions that characterize limitations the instability can impose on the implosion in terms of maximum convergence ratios attainable for an axially coherent pinch. Both the implosion and instability models are validated with results from high-resolution numerical simulations.

  6. D-D fusion experiments using fast z pinches

    SciTech Connect

    Spielman, R.B.; Baldwin, G.T.; Cooper, G.

    1994-04-01

    The development of high current (I > 10 MA) drivers provides us with a new tool for the study of neutron-producing plasmas in the thermal regime. The imploded deuterium mass (or collisionality) increases as I{sup 2} and the ability of the driver to heat the plasma to relevant fusion temperatures improves as the power of the driver increases. Additionally, fast (< 100 ns) implosions are more stable to the usual MHD instabilities that plagued the traditional slower implosions. We describe experiments in which deuterium gas puffs or CD{sub 2} fiber arrays were imploded in a fast z-pinch configuration on Sandia`s Saturn facility generating up to 3 {times} 10{sup 12} D-D neutrons. These experiments were designed to explore the physics of neutron-generating plasmas in a z-pinch geometry. Specifically, we intended to produce neutrons from a nearly thermal plasma where the electrons and ions have a nearly Maxwellian distribution. This is to be clearly differentiated from the more usual D-D beam-target neutrons generated in many dense plasma focus (DPF) devices.

  7. D-D fusion experiments using fast Z pinches

    SciTech Connect

    Spielman, R.B.; Baldwin, G.T.; Cooper, G.

    1998-03-01

    The development of high current (I > 10 MA) drivers provides the authors with a new tool for the study of neutron-producing plasmas in the thermal regime. The imploded deuterium mass (or collisionality) increases as I{sup 2} and the ability of the driver to heat the plasma to relevant fusion temperatures improves as the power of the driver increases. Additionally, fast (<100 ns) implosions are more stable to the usual MHD instabilities that plagued the traditional slower implosions. The authors describe experiments in which deuterium gas puffs or CD{sub 2} fiber arrays were imploded in a fast z-pinch configuration on Sandia`s Saturn facility generating up to 3 {times} 10{sup 12} D-D neutrons. These experiments were designed to explore the physics of neutron-generating plasmas in a z-pinch geometry. Specifically, the authors intended to produce neutrons from a nearly thermal plasma where the electrons and ions have a nearly Maxwellian distribution. This is to be clearly differentiated from the more usual D-D beam-target neutrons generated in many dense plasma focus (DPF) devices.

  8. Wire Array Z-pinches on Sphinx Machine: Experimental Results and Relevant Points of Microsecond Implosion Physics

    SciTech Connect

    Calamy, H.; Hamann, F.; Lassalle, F.; Bayol, F.; Mangeant, C.; Morell, A.; Huet, D.; Bedoch, J.P.; Chittenden, J.P.; Lebedev, S.V.; Jennings, C.A.; Bland, S.N.

    2006-01-05

    Centre d'Etudes de Gramat (France) has developed an efficient long implosion time (800 ns) Aluminum plasma radiation source (PRS). Based on the LTD technology, the SPHINX facility is developed as a 1-3MJ, 1{mu}s rise time, 4-10 MA current driver. In this paper, it was used in 1MJ, 4MA configuration to drive Aluminum nested wire arrays Z-pinches with K-shell yield up to 20 kJ and a FWHM of the x-ray pulse of about 50 ns. We present latest SPHINX experiments and some of the main physic issues of the microsecond regime. Experimental setup and results are described with the aim of giving trends that have been obtained. The main features of microsecond implosion of wire arrays can be analyzed thanks to same methods and theories as used for faster Z-pinches. The effect of load polarity was examined. The stability of the implosion , one of the critical point of microsecond wire arrays due to the load dimensions imposed by the time scale, is tackled. A simple scaling from 100 ns Z-pinch results to 800 ns ones gives good results and the use of nested arrays improves dramatically the implosion quality and the Kshell yield of the load. However, additional effects such as the impact of the return current can geometry on the implosion have to be taken into account on our loads. Axial inhomogeneity of the implosion the origin of which is not yet well understood occurs in some shots and impacts the radiation output. The shape of the radiative pulse is discussed and compared with the homogeneity of the implosion. Numerical 2D R-Z and R-{theta} simulations are used to highlight some experimental results and understand the plasma conditions during these microsecond wire arrays implosions.

  9. Wire Array Z-pinches on Sphinx Machine: Experimental Results and Relevant Points of Microsecond Implosion Physics

    NASA Astrophysics Data System (ADS)

    Calamy, H.; Hamann, F.; Lassalle, F.; Bayol, F.; Mangeant, C.; Morell, A.; Huet, D.; Bedoch, J. P.; Chittenden, J. P.; Lebedev, S. V.; Jennings, C. A.; Bland, S. N.

    2006-01-01

    Centre d'Etudes de Gramat (France) has developed an efficient long implosion time (800 ns) Aluminum plasma radiation source (PRS). Based on the LTD technology, the SPHINX facility is developed as a 1-3MJ, 1μs rise time, 4-10 MA current driver. In this paper, it was used in 1MJ, 4MA configuration to drive Aluminum nested wire arrays Z-pinches with K-shell yield up to 20 kJ and a FWHM of the x-ray pulse of about 50 ns. We present latest SPHINX experiments and some of the main physic issues of the microsecond regime. Experimental setup and results are described with the aim of giving trends that have been obtained. The main features of microsecond implosion of wire arrays can be analyzed thanks to same methods and theories as used for faster Z-pinches. The effect of load polarity was examined. The stability of the implosion , one of the critical point of microsecond wire arrays due to the load dimensions imposed by the time scale, is tackled. A simple scaling from 100 ns Z-pinch results to 800 ns ones gives good results and the use of nested arrays improves dramatically the implosion quality and the Kshell yield of the load. However, additional effects such as the impact of the return current can geometry on the implosion have to be taken into account on our loads. Axial inhomogeneity of the implosion the origin of which is not yet well understood occurs in some shots and impacts the radiation output. The shape of the radiative pulse is discussed and compared with the homogeneity of the implosion. Numerical 2D R-Z and R-θ simulations are used to highlight some experimental results and understand the plasma conditions during these microsecond wire arrays implosions.

  10. The Study of a Fibre Z-Pinch

    NASA Astrophysics Data System (ADS)

    Klir, Daniel

    2007-03-01

    This thesis presents the results of fibre Z-pinch experiments carried out on the Z-150 device at the CTU in Prague. The generator that was used to drive the experiments consisted of one capacitor of 3e-6 F capacitance. In the case of 20 kV charging voltage, the current was peaking at 80 kA with a 850 ns quarter period. The Z-pinch was formed from carbon fibres of 15 micrometer diameter and 1 cm length. The discharge was observed by a large number of diagnostic tools. This comprehensive set of diagnostics enabled us to describe the gross dynamics of the Z-pinch. It was found out that after the breakdown a low density coronal plasma was formed while the fibre diameter remained almost unchanged. This low density corona was carrying almost all the current of the order of 10 kA. When the current had built up, the implosion of the corona onto the central fibre occurred. The implosion velocity approached the value of 2e5 m/s. When the imploded corona had reached the fibre, the dip in dI/dt, voltage peak up to 10 kV, and XUV pulse of a 10-30 ns width were observed. XUV radiation was emitted from several bright spots which corresponded to the interaction of m=0 instability necks with the dense core. The electron temperature and density were approximately 80 eV and 10e25 per cubic meter, respectively. Although the presence of a fibre did not significantly suppress MHD instabilities, they were not disruptive. After the fibre ablation, i.e. after 500 ns, material evaporated from electrodes started to play a dominant role. The observed plasma column seemed to be MHD unstable and when m=0 instabilities had developed, X-ray pulses were emitted from several hot spots, particularly near the anode. At that time the voltage peak of up to 30 kV was detected.

  11. High Power Selective Laser Melting (HP SLM) of Aluminum Parts

    NASA Astrophysics Data System (ADS)

    Buchbinder, D.; Schleifenbaum, H.; Heidrich, S.; Meiners, W.; Bültmann, J.

    Selective Laser Melting (SLM) is one of the Additive Manufacturing (AM) technologies that enables the production of light weight structured components with series identical mechanical properties without the need for part specific tooling or downstream sintering processes, etc. Especially aluminum is suited for such eco-designed components due to its low weight and superior mechanical and chemical properties. However, SLM's state-of-the-art process and cost efficiency is not yet suited for series-production. In order to improve this efficiency it is indispensable to increase the build rate significantly. Thus, aluminum is qualified for high build rate applications using a new prototype machine tool including a 1 kW laser and a multi-beam system.

  12. A kind of fast shutter for Z pinch diagnosis device

    NASA Astrophysics Data System (ADS)

    Wang, Liangping; Zhang, Xinjun; Sun, Tieping; Mao, Wentin

    2016-09-01

    A kind of fast shutter for protecting the diagnosis devices in Z pinch experiments is introduced in this paper. The shutter is composed of a pulling rod, a magnetic core, and a solenoid. Different from the traditional coils which were used at the voltage of 220 V, the solenoid we used must endure the high voltage of 5-10 kV and the deformation which maybe caused by the 5-10 T intense magnetic field. A creative configuration for the solenoid is developed including the winding guide, insulating sleeve, and stainless-steel sleeve. The experimental results show that the configuration of the solenoid is effective. The velocity of the valve is nearly 19 m/s and the time jitter of the shutdown is within 75 μs.

  13. Spectroscopic study of z-pinch stagnation on Z.

    SciTech Connect

    Maron, Yitzhak; Weingarten, L.; Starobinets, A.; Fisher, V.; Jennings, Christopher A.; Ampleford, David J.; Bailey, James E.; Yu, Edmund P.; Bernshtam, V.; Cuneo, Michael Edward; Rochau, Gregory Alan; Coverdale, Christine Anne; Jones, Brent Manley; Hansen, Stephanie B.

    2010-11-01

    Fast z-pinches provide intense 1-10 keV photon energy radiation sources. Here, we analyze time-, space-, and spectrally-resolved {approx}2 keV K-shell emissions from Al (5% Mg) wire array implosions on Sandia's Z machine pulsed power driver. The stagnating plasma is modeled as three separate radial zones, and collisional-radiative modeling with radiation transport calculations are used to constrain the temperatures and densities in these regions, accounting for K-shell line opacity and Doppler effects. We discuss plasma conditions and dynamics at the onset of stagnation, and compare inferences from the atomic modeling to three-dimensional magneto-hydrodynamic simulations.

  14. Instability Control in a Staged Z-pinch

    SciTech Connect

    WESSEL, Frank J

    2011-04-22

    A \\Staged Z-Pinch is a fusion-energy concept in which stored-electric energy is first converted into plasma-liner-kinetic energy, and then transferred to a coaxialtarget plasma [H. U. Rahman, F. J. Wessel, and N. Rostoker, Phys. Rev. Lett. 74, p. 714(1996)]. Proper choice of the liner and target materials, and their initial radii and mass densities, leads to dynamic stabilization, current amplification, and shock heating of the target. Simulations suggest that this configuration has merit as a alternative inertial-confinement-fusion concept, and may provide an energy release exceeding thermonuclear break-even, if tested on one of many newer pulsed power systems, for example those located at Sandia National Laboratories.

  15. Tungsten Z-Pinch Long Implosions on the Saturn Generator

    SciTech Connect

    DOUGLAS,MELISSA R.; DEENEY,CHRISTOPHER; SPIELMAN,RICK B.; COVERDALE,CHRISTINE A.; RODERICK,N.F.; HAINES,M.G.

    1999-11-05

    Recent success on the Saturn and Z accelerators at Sandia National Laboratories have demonstrated the ability to scale z-pinch parameters to increasingly larger current pulsed power facilities. Next generation machines will require even larger currents (>20 MA), placing further demands on pulsed power technology. To this end, experiments have been carried out on Saturn operating in a long pulse mode, investigating the potential of lower voltages and longer implosion times while still maintaining pinch fidelity. High wire number, 25 mm diameter tungsten arrays were imploded with implosion times ranging from 130 to 240 ns. The results were comparable to those observed in the Saturn short pulse mode, with risetimes on the order of 4.5 to 6.5 ns. Experimental data will be presented, along with two dimensional radiation magnetohydrodynamic simulations used to explain and reproduce the experiment.

  16. Light detonation wave in a cylindrical Z-pinch

    NASA Astrophysics Data System (ADS)

    Yusupaliev, U.; Sysoev, N. N.; Shuteev, S. A.; Elenskii, V. G.

    2015-09-01

    A secondary compression wave previously observed by other researchers in a cylindrical Z-pinch has been identified in this work as a light detonation wave. It appears on the inner surface of a discharge chamber under the action of the intense ultraviolet radiation from a plasma pinch at the stage of its maximum compression. The condition of the light detonation wave has been determined experimentally. The dependence of its Mach number on a generalized dimensionless variable has been determined taking into account the conservation laws for the light detonation wave including the pressure of the gas, expenses on the formation of the surface plasma, and the energy of ionization of the gas involved in the wave. An analogy with the laser-supported detonation wave created by intense laser radiation has been revealed. The indicated dependence is within the error of measurement in agreement with the experimental data for light detonation waves created by both methods.

  17. Conceptual Design of a Z-Pinch Fusion Propulsion System

    NASA Technical Reports Server (NTRS)

    Adams, Robert; Polsgrove, Tara; Fincher, Sharon; Fabinski, Leo; Maples, Charlotte; Miernik, Janie; Stratham, Geoffrey; Cassibry, Jason; Cortez, Ross; Turner, Matthew; Santarius, John; Percy, Thomas

    2010-01-01

    This slide presentation reviews a project that aims to develop a conceptual design for a Z-pinch thruster, that could be applied to develop advanced thruster designs which promise high thrust/high specific impulse propulsion. Overviews shows the concept of the design, which use annular nozzles with deuterium-tritium (D-T) fuel and a Lithium mixture as a cathode, Charts show the engine performance as a function of linear mass, nozzle performance (i.e., plasma segment trajectories), and mission analysis for possible Mars and Jupiter missions using this concept for propulsion. Slides show views of the concepts for the vehicle configuration, thrust coil configuration, the power management system, the structural analysis of the magnetic nozzle, the thermal management system, and the avionics suite,

  18. Wire Array Z-pinch Insights for Intense X-ray Power Production

    NASA Astrophysics Data System (ADS)

    Sanford, T. W. L.

    1998-11-01

    The discovery [1] that the use of very large numbers of wires enables high x- ray power to be generated from wire-array z-pinches represents a breakthrough in load design for large pulsed power generators, and has permitted high temperatures to be generated in radiation cavities [2] on Saturn [3] and Z [4]. In this paper, changes in x-ray emission characteristics as a function of wire number, array mass, and load radius, for 20-mm-long aluminum arrays on Saturn that led to these breakthrough hohlraum results, are discussed and compared with a few related emission characteristics of high-wire-number aluminum and tungsten arrays on Z. In this discussion, the detailed measurements made with bolometers, filtered XRDs and PCDs, time resolved filtered x-ray pinhole cameras and crystal spectrometers are given meaning by comparison with one, two, and three dimensional radiation-magnetohydrodynamic code simulations. [1] T. W. L. Sanford, et al., Phys. Rev. Lett. 77, 5063 (1996). [2] M. K. Matzen, Phys. Plasmas 4, 1519 (1997). [3] D. D. Bloomquist, et al., Proc. 6th Int. IEEE Pulsed Power Conf., (1987), p. 310. [4] R. B. Spielman, et al., Phys. Plasmas 5, 2105 (1998).

  19. A non-LTE kinetic model for quick analysis of K-shell spectra from Z-pinch plasmas

    SciTech Connect

    Li, J. Huang, X. B. Cai, H. C. Yang, L. B. Xie, W. P. Duan, S. C.

    2014-12-15

    Analyzing and modeling K-shell spectra emitted by low-to moderate-atomic number plasma is a useful and effective way to retrieve temperature density of z-pinch plasmas. In this paper, a non-LTE population kinetic model for quick analysis of K-shell spectra was proposed. The model contains ionization stages from bare nucleus to neutral atoms and includes all the important atomic processes. In the present form of the model, the plasma is assumed to be both optically thin and homogeneous with constant temperature and density, and only steady-state situation is considered. According to the detailed calculations for aluminum plasmas, contours of ratios of certain K-shell lines in electron temperature and density plane as well as typical synthesized spectra were presented and discussed. The usefulness of the model is demonstrated by analyzing the spectrum from a neon gas-puff Z-pinch experiment performed on a 1 MA pulsed-power accelerator.

  20. Current redistribution and generation of kinetic energy in the stagnated Z pinch.

    PubMed

    Ivanov, V V; Anderson, A A; Papp, D; Astanovitskiy, A L; Talbot, B R; Chittenden, J P; Niasse, N

    2013-07-01

    The structure of magnetic fields was investigated in stagnated wire-array Z pinches using a Faraday rotation diagnostic at the wavelength of 266 nm. The distribution of current in the pinch and trailing material was reconstructed. A significant part of current can switch from the main pinch to the trailing plasma preheated by x-ray radiation of the pinch. Secondary implosions of trailing plasma generate kinetic energy and provide enhanced heating and radiation of plasma at stagnation. Hot spots in wire-array Z pinches also provide enhanced radiation of the Z pinch. A collapse of a single hot spot radiates 1%-3% of x-ray energy of the Z pinch with a total contribution of hot spots of 10%-30%.

  1. Study of soft X-ray emission from Z-pinches with a complex atomic composition

    SciTech Connect

    Volkov, G. S.; Zaitsev, V. I.; Grabovski, E. V.; Fedulov, M. V.; Aleksandrov, V. V.; Lakhtyushko, N. I.

    2010-03-15

    Results are presented from experimental studies of Z-pinches produced by implosion of aluminum and tungsten cylindrical wire arrays in the Angara-5-1 facility. The electron temperature T{sub e} and density n{sub e} of the high-temperature pinch plasma have been determined by analyzing line emission from multicharged ions. For the same mass and radius of the array and the same number of wires in it, the intensity of line emission of H- and He-like Al ions from an imploded Al + W wire array containing even a small amount of tungsten (7 wt %) is one order of magnitude lower than that from an Al array. As the W content increases, the total soft X-ray (SXR) yield increases, while the duration of the SXR pulse decreases. For the 30% W content in the array, the power and duration of the SXR pulse are nearly the same as those recorded during the implosion of a W array with the same linear mass and radius and the same number of wires. Results are also presented from experiments with nested wire arrays in which the outer and inner shells were made of Al and W wires, respectively. It is found that, in this case, the effect of tungsten on the line emission of aluminum is much weaker than that in experiments with arrays in which tungsten and aluminum wires were placed in the same shell, even if the mass of the inner (tungsten) shell was larger than that of the outer (aluminum) one. At the same time, the inner W shell plays a significant role in the implosion dynamics of a nested wire array, reducing the duration of the SXR pulse and increasing the SXR power.

  2. Electromagnetic Wave Propagation Through the ZR Z-Pinch Accelerator

    SciTech Connect

    Rose, D. V.; Welch, D. R.; Madrid, E. A.; Miller, C. L.; Clark, R. E.; Stygar, W. A.; Struve, K.; Corcoran, P. A.; Whitney, B.

    2009-01-21

    A fully three-dimensional electromagnetic model of the major pulsed power components of the 26-MA ZR accelerator is presented. This large-scale simulation model tracks the evolution of electromagnetic waves through the intermediate storage capacitors, laser-triggered gas switches, pulse-forming lines, water switches, tri-plate transmission lines, and water convolute to the vacuum insulator stack. The plates at the insulator stack are coupled to a transmission line circuit model of the four-level magnetically-insulated transmission line section and post-hole convolutes. The vacuum section circuit model is terminated by either a short-circuit load or dynamic models of imploding z-pinch loads. The simulations results are compared with electrical measurements made throughout the ZR accelerator and good agreement is found, especially for times before and up to peak load power. This modeling effort represents new opportunities for modeling existing and future large-scale pulsed power systems used in a variety of high energy density physics and radiographic applications.

  3. Viscous Heating At Stagnation In Z-Pinches

    SciTech Connect

    Haines, M. G.

    2009-01-21

    The viscous heating associated with m = 0 MHD instabilities in the stagnated Z-pinch is developed further. It would appear that the larger numerical (Neumann) viscosity plus De Bar corrections in simulation codes to yield energy conservation might be another way of representing viscous heating, but in this case the viscosity is inserted to smooth shock discontinuities. However the viscous heating per unit volume appears to be independent of the coefficient of viscosity itself because the fastest growing MHD mode is itself determined by the viscous damping. Therefore it could be argued that, though the correct physics is not in the codes, the resulting heating is not sensitive to the fact that numerical viscosity instead is employed. In addition, by chance, the model of magnetic bubbles first introduced by Lovberg et al. and Riley et al., and later by Rudakov et al. to explain phenomenologically extra heating of the ions leads to the same heating rate as in Haines et al. For the stainless steel array in which T{sub i} was predicted and measured to be >200 KeV while T{sub e} = 3 KeV the ion viscous heating is dominant. However, for the low current experiment by Kroupp et al. in which the ion kinematic viscosity is much smaller than the resistive diffusivity there is resistive damping of MHD modes, and no ions viscous heating should be expected.

  4. Polytropic scaling of a flow Z-pinch

    NASA Astrophysics Data System (ADS)

    Hughes, M. C.; Shumlak, U.; Nelson, B. A.; Golingo, R. P.; Claveau, E. L.; Doty, S. A.; Forbes, E. G.; Kim, B.; Ross, M. P.; Weed, J. R.

    2015-11-01

    The ZaP Flow Z-Pinch project investigates the use of velocity shear to mitigate MHD instabilities. The ZaP-HD experiment produces 50 cm long pinches of varying radii. The power to the experiment is split between the plasma formation and acceleration process and the pinch assembly and compression process. Once the pinch is formed, low magnetic fluctuations indicate a quiescent, long-lived pinch. The split power supply allows more control of the pinch current than previous machine iterations, with a designed range from 50 to 150 kA. Radial force balance leads to the Bennett relation which indicates that as the pinch compresses due to increasing currents, the plasma pressure and/or linear density must change. Through ion spectroscopy and digital holographic interferometry coupled with magnetic measurements of the pinch current, the components of the Bennett relation can be fully measured. A scaling relation is then assumed to follow a polytrope as the pinch pressure, initially approximately 250 kPa, increases from an initially formed state to much higher values, approaching 100 MPa. A preliminary analysis of pinch scaling is shown corroborating with other diagnostics on the machine along with extrapolations to required currents for an HEDLP machine. This work is supported by grants from the U.S. Department of Energy and the U.S. National Nuclear Security Administration.

  5. Diagnostics for Z-pinch implosion experiments on PTS

    NASA Astrophysics Data System (ADS)

    Ren, X. D.; Huang, X. B.; Zhou, S. T.; Zhang, S. Q.; Dan, J. K.; Li, J.; Cai, H. C.; Wang, K. L.; Ouyang, K.; Xu, Q.; Duan, S. C.; Chen, G. H.; Wang, M.; Feng, S. P.; Yang, L. B.; Xie, W. P.; Deng, J. J.

    2014-12-01

    The preliminary experiments of wire array implosion were performed on PTS, a 10 MA z-pinch driver with a 70 ns rise time. A set of diagnostics have been developed and fielded on PTS to study pinch physics and implosion dynamics of wire array. Radiated power measurement for soft x-rays was performed by multichannel filtered x-ray diode array, and flat spectral responses x-ray diode detector. Total x-ray yield was measured by a calibrated, unfiltered nickel bolometer which was also used to obtain pinch power. Multiple time-gated pinhole cameras were used to produce spatial-resolved images of x-ray self-emission from plasmas. Two time-integrated pinhole cameras were used respectively with 20-μm Be filter and with multilayer mirrors to record images produced by >1-keV and 277±5 eV self-emission. An optical streak camera was used to produce radial implosion trajectories, and an x-ray streak camera paired with a horizontal slit was used to record a continuous time-history of emission with one-dimensional spatial resolution. A frequency-doubled Nd:YAG laser (532 nm) was used to produce four frame laser shadowgraph images with 6 ns time interval. We will briefly describe each of these diagnostics and present some typical results from them.

  6. Diagnostics for Z-pinch implosion experiments on PTS

    SciTech Connect

    Ren, X. D. Huang, X. B. Zhou, S. T. Zhang, S. Q. Dan, J. K. Li, J. Cai, H. C. Wang, K. L. Ouyang, K. Xu, Q. Duan, S. C. Chen, G. H. Wang, M. Feng, S. P. Yang, L. B. Xie, W. P. Deng, J. J.

    2014-12-15

    The preliminary experiments of wire array implosion were performed on PTS, a 10 MA z-pinch driver with a 70 ns rise time. A set of diagnostics have been developed and fielded on PTS to study pinch physics and implosion dynamics of wire array. Radiated power measurement for soft x-rays was performed by multichannel filtered x-ray diode array, and flat spectral responses x-ray diode detector. Total x-ray yield was measured by a calibrated, unfiltered nickel bolometer which was also used to obtain pinch power. Multiple time-gated pinhole cameras were used to produce spatial-resolved images of x-ray self-emission from plasmas. Two time-integrated pinhole cameras were used respectively with 20-μm Be filter and with multilayer mirrors to record images produced by >1-keV and 277±5 eV self-emission. An optical streak camera was used to produce radial implosion trajectories, and an x-ray streak camera paired with a horizontal slit was used to record a continuous time-history of emission with one-dimensional spatial resolution. A frequency-doubled Nd:YAG laser (532 nm) was used to produce four frame laser shadowgraph images with 6 ns time interval. We will briefly describe each of these diagnostics and present some typical results from them.

  7. Analytic model for the dynamic Z-pinch

    SciTech Connect

    Piriz, A. R. Sun, Y. B.; Tahir, N. A.

    2015-06-15

    A model is presented for describing the cylindrical implosion of a shock wave driven by an accelerated piston. It is based in the identification of the acceleration of the shocked mass with the acceleration of the piston. The model yields the separate paths of the piston and the shock. In addition, by considering that the shocked region evolves isentropically, the approximate profiles of all the magnitudes in the shocked region are obtained. The application to the dynamic Z-pinch is presented and the results are compared with the well known snowplow and slug models which are also derived as limiting cases of the present model. The snowplow model is seen to yield a trajectory in between those of the shock and the piston. Instead, the neglect of the inertial effects in the slug model is seen to produce a too fast implosion, and the pressure uniformity is shown to lead to an unphysical instantaneous piston stopping when the shock arrives to the axis.

  8. Implicit XMHD Modeling of Fast Z-Pinches

    NASA Astrophysics Data System (ADS)

    Martin, Matthew

    2013-10-01

    The numerical modeling of fast Z-Pinches as applied to magnetically driven inertial confinement fusion concepts is typically performed under the resistive- magnetohydrodynamic (MHD) model. We derive the limitations of this model as currently applied to modeling such targets and present numerical test problems that demonstrate the physical error introduced through the approximations inherent in resistive-MHD. We then compare the resistive-MHD model to simulations utilizing new implicit algorithms for the efficient solution of the extended-magnetohydrodynamic (XMHD) system of equations. Herein we define XMHD as a quasi-neutral electro-magnetic two-fluid model. We present specific examples where the XMHD system of equations is required for modeling magnetically driven ICF targets if large physical errors are to be avoided in the numerical solution of the system. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Study of gas-puff Z-pinches on COBRA

    SciTech Connect

    Qi, N.; Rosenberg, E. W.; Gourdain, P. A.; Grouchy, P. W. L. de; Kusse, B. R.; Hammer, D. A.; Bell, K. S.; Shelkovenko, T. A.; Potter, W. M.; Atoyan, L.; Cahill, A. D.; Evans, M.; Greenly, J. B.; Hoyt, C. L.; Pikuz, S. A.; Schrafel, P. C.; Kroupp, E.; Fisher, A.; Maron, Y.

    2014-11-15

    Gas-puff Z-pinch experiments were conducted on the 1 MA, 200 ns pulse duration Cornell Beam Research Accelerator (COBRA) pulsed power generator in order to achieve an understanding of the dynamics and instability development in the imploding and stagnating plasma. The triple-nozzle gas-puff valve, pre-ionizer, and load hardware are described. Specific diagnostics for the gas-puff experiments, including a Planar Laser Induced Fluorescence system for measuring the radial neutral density profiles along with a Laser Shearing Interferometer and Laser Wavefront Analyzer for electron density measurements, are also described. The results of a series of experiments using two annular argon (Ar) and/or neon (Ne) gas shells (puff-on-puff) with or without an on- (or near-) axis wire are presented. For all of these experiments, plenum pressures were adjusted to hold the radial mass density profile as similar as possible. Initial implosion stability studies were performed using various combinations of the heavier (Ar) and lighter (Ne) gasses. Implosions with Ne in the outer shell and Ar in the inner were more stable than the opposite arrangement. Current waveforms can be adjusted on COBRA and it was found that the particular shape of the 200 ns current pulse affected on the duration and diameter of the stagnated pinched column and the x-ray yield.

  10. Optimized Minimal Inductance Transmission Line Configuration for Z-Pinch Experiments

    SciTech Connect

    Hurricane, O

    2003-10-16

    Successful dynamic Z-pinch experiments generally require good current delivery to the target load. Power flow losses through highly inductive transmission line configurations reduce the current available to the load. In this Brief Report, a variational calculus technique is used to determine the transmission line configuration that produces the least possible inductance and therefore the best possible current delivery for Z-pinch experiments.

  11. Development of laser-based diagnostics for 1-MA z-pinch plasmas

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.; Hakel, P.; Mancini, R. C.; Wiewior, P.; Presura, R.; Kindel, J. M.; Shevelko, A. P.; Chalyy, O.; Astanovitskiy, A.; Haboub, A.; Altemara, S. D.; Papp, D.; Durmaz, T.

    2009-11-01

    The 50 TW Leopard laser coupled with the 1-MA Zebra generator was used for development of new diagnostics of z-pinch plasmas. Two plasma diagnostics are presented: an x-ray broadband backlighting for z-pinch absorption spectroscopy and parametric two-plasmon decay of the laser beam in dense z-pinch plasma. Implementation of new diagnostics on the Zebra generator and the first results are discussed. The absorption spectroscopy is based on backlighting of z-pinch plasma with a broadband x-ray radiation from a Sm laser plasma. Detailed analysis of the absorption spectra yields the electron temperature and density of z-pinch plasma at the non-radiative stage. The parametric two-plasmon decay of intensive laser radiation generates 3/2φ and 1/2φ harmonics. These harmonics can be used to derive a temperature of z-pinch plasma with the electron density near the quarter of critical plasma density.

  12. PBFA Z: A 20-MA z-pinch driver for plasma radiation sources

    SciTech Connect

    Spielman, R.B.; Breeze, S.F.; Deeney, C.

    1996-07-01

    Sandia National Laboratories is completing a major modification to the PBFA-II facility. PBFA Z will be a z-pinch driver capable of delivering up to 20 MA to a z-pinch load. It optimizes the electrical coupling to the implosion energy of z pinches at implosion velocities of {approximately} 40 cm/{mu}s. Design constraints resulted in an accelerator with a 0.12-{Omega} impedance, a 10.25-nH inductance, and a 120-ns pulse width. The design required new water transmission lines, insulator stack, and vacuum power feeds. Current is delivered to the z-pinch load through four, self-magnetically-insulated vacuum transmission lines and a double post-hole convolute. A variety of design codes are used to model the power flow. These predict a peak current of 20 MA to a z-pinch load having a 2-cm length, a 2-cm radius, and a 15--mg mass, coupling 1.5 MJ into kinetic energy. We present 2-D Rad-Hydro calculations showing MJ x-ray outputs from tungsten wire-array z pinches.

  13. Preliminary Results of a 10 kJ Z-Pinch

    SciTech Connect

    Cortazar, O. D.; Piriz, A. R.; Prieto, G. Rodriguez; Hoffmann, D. H. H.; Tahir, N. A.

    2008-04-07

    Preliminary results obtained on 10 kJ Z-pinch device developed at the Plasma and Electrical Discharge Laboratory in the University of Castilla-La Mancha are presented. The device called ENERGU-1 is composed by 8 capacitors (0.5 {mu}F, 75 kV, 20 nH) connected in parallel to a discharge chamber by means of one high power plane transmission line by mean of 8 spark-gaps switches triggered by a 100 kV, 13 ns trigger pulse. The discharge chamber is a cylindrical Pyrex glass tube externally surrounded by a SF{sub 6} isolation atmosphere with the electrodes at the ends. Two different chambers have been studied by discharging the capacitor bank energy in deuterium for optimizing the D-D nuclear fusion reactions: one of 100 mm long by 100 mm inner diameter and the other of the same length and 70 mm inner diameter. Several sequences of ultrahigh speed converter camera photography (5 ns) are presented showing the implosion of plasma columns for different deuterium pressure and currents. Preliminary measurements of integrated 2.45 MeV neutron emissions by a silver activated neutron counter are analyzed as a function of electrical and constructive parameters. A yield of 10{sup 7}-10{sup 8} D-D fusion reactions by shot is reported when the optimum conditions are reached conducting currents of 400-600 kA with a plasma column lifetime above 100 ns.

  14. Soldered Contact and Current Risetime Effects on Negative Polarity Wire Array Z-pinches

    SciTech Connect

    Chalenski, D. A.; Kusse, B. R.; Greenly, J. B.; Blesener, I. C.; McBride, R. D.; Hammer, D. A.; Knapp, P. F.

    2009-01-21

    The Cornell University COBRA pulser is a nominal 1 MA machine, capable of driving up to 32 wire cylindrical Z-pinch arrays. COBRA can operate with variable current risetimes ranging from 100 ns to 200 ns (short and long pulse, respectively). Wires are typically strung with a 'press' contact to the electrode hardware, where the wire is loosely pulled against the hardware and held there to establish electrical contact. The machine is normally negative, but a bolt-on convolute can be used to modify the current path and effectively produce positive polarity operation at the load.Previous research with single wires on a 1-5 kA pulser has shown that soldering the wire, thereby improving the wire/electrode contact, and operating in positive polarity can improve the energy deposition into the wire and enhance wire core expansion. Negative polarity showed no difference. Previous experiments on the negative polarity, 20 MA, 100 ns Z accelerator have shown that improving the contact improved the x-ray yield.Cornell data were collected on 16-wire Aluminum Z-pinch arrays in negative polarity. Experiments were conducted with both short and long current pulses with soldered and no-soldered wire/electrode contacts. The initiation, ablation, implosion and stagnation phases were compared for these four conditions. Time dependent x-ray signals were measured using diodes and diamond detectors. An inductive voltage monitor was used to infer minimum current radius achieved, as defined by a uniform shell of current moving radially inward, producing a time dependent inductance. Total energy data were collected with a metal-strip bolometer. Self-emission data were collected by an XUV 4-frame camera and an optical streak camera.In negative polarity and with short pulses, soldering appeared to produce a smaller radius pinch and decrease variations in the x-ray pulse shape. The bolometer, laser backlighter, 4-frame and streak cameras showed negligible differences in the initiation ablation

  15. High-power Laser Welding of Thick Steel-aluminum Dissimilar Joints

    NASA Astrophysics Data System (ADS)

    Lahdo, Rabi; Springer, André; Pfeifer, Ronny; Kaierle, Stefan; Overmeyer, Ludger

    According to the Intergovernmental Panel on Climate Change (IPCC), a worldwide reduction of CO2-emissions is indispensable to avoid global warming. Besides the automotive sector, lightweight construction is also of high interest for the maritime industry in order to minimize CO2-emissions. Using aluminum, the weight of ships can be reduced, ensuring lower fuel consumption. Therefore, hybrid joints of steel and aluminum are of great interest to the maritime industry. In order to provide an efficient lap joining process, high-power laser welding of thick steel plates (S355, t = 5 mm) and aluminum plates (EN AW-6082, t = 8 mm) is investigated. As the weld seam quality greatly depends on the amount of intermetallic phases within the joint, optimized process parameters and control are crucial. Using high-power laser welding, a tensile strength of 10 kN was achieved. Based on metallographic analysis, hardness tests, and tensile tests the potential of this joining method is presented.

  16. Theoretical z -pinch scaling relations for thermonuclear-fusion experiments.

    PubMed

    Stygar, W A; Cuneo, M E; Vesey, R A; Ives, H C; Mazarakis, M G; Chandler, G A; Fehl, D L; Leeper, R J; Matzen, M K; McDaniel, D H; McGurn, J S; McKenney, J L; Muron, D J; Olson, C L; Porter, J L; Ramirez, J J; Seamen, J F; Speas, C S; Spielman, R B; Struve, K W; Torres, J A; Waisman, E M; Wagoner, T C; Gilliland, T L

    2005-08-01

    We have developed wire-array z -pinch scaling relations for plasma-physics and inertial-confinement-fusion (ICF) experiments. The relations can be applied to the design of z -pinch accelerators for high-fusion-yield (approximately 0.4 GJ/shot) and inertial-fusion-energy (approximately 3 GJ/shot) research. We find that (delta(a)/delta(RT)) proportional (m/l)1/4 (Rgamma)(-1/2), where delta(a) is the imploding-sheath thickness of a wire-ablation-dominated pinch, delta(RT) is the sheath thickness of a Rayleigh-Taylor-dominated pinch, m is the total wire-array mass, l is the axial length of the array, R is the initial array radius, and gamma is a dimensionless functional of the shape of the current pulse that drives the pinch implosion. When the product Rgamma is held constant the sheath thickness is, at sufficiently large values of m/l, determined primarily by wire ablation. For an ablation-dominated pinch, we estimate that the peak radiated x-ray power P(r) proportional (I/tau(i))(3/2)Rlphigamma, where I is the peak pinch current, tau(i) is the pinch implosion time, and phi is a dimensionless functional of the current-pulse shape. This scaling relation is consistent with experiment when 13 MA < or = I < or = 20 MA, 93 ns < or = tau(i) < or = 169 ns, 10 mm < or = R < or = 20 mm, 10 mm < or = l < or = 20 mm, and 2.0 mg/cm < or = m/l < or = 7.3 mg/cm. Assuming an ablation-dominated pinch and that Rlphigamma is held constant, we find that the x-ray-power efficiency eta(x) congruent to P(r)/P(a) of a coupled pinch-accelerator system is proportional to (tau(i)P(r)(7/9 ))(-1), where P(a) is the peak accelerator power. The pinch current and accelerator power required to achieve a given value of P(r) are proportional to tau(i), and the requisite accelerator energy E(a) is proportional to tau2(i). These results suggest that the performance of an ablation-dominated pinch, and the efficiency of a coupled pinch-accelerator system, can be improved substantially by decreasing the

  17. Stand-off energy sources for Z-pinch implosions

    SciTech Connect

    Ryutov, D; Toor, A

    1999-07-12

    An issue of stand-off energy sources is in an early stage of development. Several concepts have been identified as potential solution of the problem. Those based on the total disconnection between the target assembly and the primary energy source have an obvious advantage in that they allow one to relatively easily protect the permanent part. Indeed, a fast projectile travelling at the velocity of 10 km/s covers the distance of 10 m in 1 ms, the time that is sufficient to mechanically shield the line of site. Auxiliary power supply in the form of an electron beam can be protected by using a magnetic wiggling in the transport channel in the permanent part of the facility. Of some help is also the fact that this auxiliary source operates 10 or so microseconds before the fusion energy release occurs. Another advantage of this approach is related to its compatibility with high rep-rate mode, up to tens pulses per second (because there is no need to insert heavy large-volume parts into the reaction chamber). An obvious disadvantage is that the assembly should contain a more or less complex on-board circuitry. Those concepts that are based on the direct mechanical connection between the external pulse-forming line and the disposable inner part of the transmission line (connected in turn to the Z-pinch diode) have an obvious advantage in eliminating any intermediate steps in delivering the energy to the pinch. They work essentially as the presently used Z-pinch devices and should provide the same high efficiency. A difficulty of this approach is related to the presence of the insulating slot in the walls of the reaction chamber that directly links the disposable inner part of the energy transmission system and permanent external energy source. The slot is vulnerable to mechanical perturbations and neutron irradiation that may propagate into the permanent part of the source and cause a damage to it. Mechanical damage could be reduced by the technique of hydrodynamic

  18. Fusion burn dynamics in dense Z-pinch (DZP)

    SciTech Connect

    Krakowski, R.A.

    1990-04-01

    The fusion burn dynamics and energy yield of the dense Z-pinch (DZP) are examined using a profile-averaged, zero-dimensional, time dependent model. A range of conditions (fuel, line density, voltage, fusion-product heating, enthalpy endloss, density and temperature profiles, current rise rate, electrode impurities) are examined. Magneto-hydrodynamic stability is assumed, and initial conditions are based on those ideally existing after the melting and ionization of a solid fiber of fusion fuel. Plasma conditions required of neutron sources for materials testing ({dot S}{sub n} {ge} 10{sup 19} n/s) and for possible commercial power production (ratio of fusion energy yield to energy input, Q{sub p} {approx equal} 15, lower values if reversible recovery of a fraction of the magnetic energy is possible) are described. If f{sub B} {approx gt} 0.8 fractional fuel burnup is possible in a nominal 800-ns DT discharge (200-ns current-rise phase at 20 MV/m followed by a 500-ns constant-current crowbarred phase), reactor-relevant values of Q{sub p} may be possible. For the simpler (and shorter) constant-voltage discharge (e.g., no voltage crowbar) the value of Q{sub p} is in the range 5--10 for discharges below 200-ns duration. Smaller levels of fuel burnup, shorter discharges, or generally lower levels of Q{sub p} will require a reversible energy transfer system to meet reactor energy-balance requirements. Imposition of a plasma current rise-time constraint that may be needed for stable plasma operation (e.g., I > 10{sup 12} A/s) will burnup, Q{sub p} and discharge time to an extent where reversible energy/transfer system will be required to meet reactor energy- balance requirements. 25 refs.

  19. Application of Proton Deflectometry to Z-Pinch Plasma Systems at the Mega-Ampere Scale

    NASA Astrophysics Data System (ADS)

    Mariscal, Derek; McGuffey, Chris; Valenzuela, Julio; Wei, Mingsheng; Beg, Farhat; Presura, Radu; Haque, Showera; Arias, Angel; Covington, Aaron; Sawada, Hiroshi; Chittenden, Jeremy

    2013-10-01

    Measuring magnetic fields in z-pinch plasmas is challenging. Typical laser-probing diagnostics are limited by the critical density and large density gradients, while electrical diagnostics have limited spatial resolution. We report the first demonstration of proton deflectometry of z-pinch plasma systems at the mega-ampere scale. The proton beam was produced using the 10J 0.3ps Leopard laser and coupled to z-pinch plasma produced by Zebra, a 1MA pulsed-power driver at the Nevada Terawatt Facility. The magnetic field distorted the proton beam profile, which was recorded on radiochromic film. The experimental data was compared against integrated modeling using the resistive MHD code, Gorgon, for Z-pinch plasmas, in combination with the hybrid PIC code, LSP, for proton-beam trajectory tracking. This comparison provided the field and current configuration for various plasma loads, including wire and foil z-pinches. Funded by the NSF/DoE Partnership in Basic Plasma Scienceand En- gineering under contracts DE-SC-0001992 / PHY-0903876. Use of the Nevada Terawatt Facility was supported by the US DOE, NNSA, under Contract No. DE-FC52-06NA27616.

  20. Development of the 50 TW laser for joint experiments with 1 MA z-pinches

    NASA Astrophysics Data System (ADS)

    Wiewior, P. P.; Ivanov, V. V.; Chalyy, O.

    2010-08-01

    A 50 TW high-intensity laser (aka "Leopard" laser) was developed for experiments with the 1 MA z-pinch generator at the University of Nevada, Reno. The laser produces short pulses of 0.35 ps; energy is 15 J. Long pulses are 1 ns; energy is 30 J. The output beam diameter is 80 mm. The Leopard laser applies chirped pulse amplification technology. The laser is based on the 130 fs Ti:Sapphire oscillator, Öffner-type stretcher, Ti:Sapphire regenerative amplifier, mixed Nd:glass rod and disk amplifiers, and vacuum grating compressor. An adaptive optics system ameliorates focusing ability and augments the repetition rate. Two beam terminals are available for experiments: in the vacuum chamber of the z-pinch generator (aka "Zebra"), and a laser-only vacuum chamber (aka "Phoenix" chamber). The Leopard laser coupled to the Zebra z-pinch generator is a powerful diagnostic tool for dense z-pinch plasma. We outline the status, design, architecture and parameters of the Leopard laser, and its coupling to Zebra. We present the methods of laser-based z-pinch plasma diagnostics, which are under development at the University of Nevada, Reno.

  1. ZaP-HD: High Energy Density Z-Pinch Plasmas using Sheared Flow Stabilization

    NASA Astrophysics Data System (ADS)

    Golingo, R. P.; Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Ross, M. P.; Weed, J. R.

    2015-11-01

    The ZaP-HD flow Z-pinch project investigates scaling the flow Z-pinch to High Energy Density Plasma, HEDP, conditions by using sheared flow stabilization. ZaP used a single power supply to produce 100 cm long Z-pinches that were quiescent for many radial Alfven times and axial flow-through times. The flow Z-pinch concept provides an approach to achieve HED plasmas, which are dimensionally large and persist for extended durations. The ZaP-HD device replaces the single power supply from ZaP with two separate power supplies to independently control the plasma flow and current in the Z-pinch. Equilibrium is determined by diagnostic measurements of the density with interferometry and digital holography, the plasma flow and temperature with passive spectroscopy, the magnetic field with surface magnetic probes, and plasma emission with optical imaging. The diagnostics fully characterize the plasma from its initiation in the coaxial accelerator, through the pinch, and exhaust from the assembly region. The plasma evolution is modeled with high resolution codes: Mach2, WARPX, and NIMROD. Experimental results and scaling analyses are presented. This work is supported by grants from the U.S. Department of Energy and the U.S. National Nuclear Security Administration.

  2. A Gas Embedded Z-pinch Driven by SPEED2 Generator

    SciTech Connect

    Soto, Leopoldo; Moreno, Jose; Sylvester, Gustavo; Silva, Patricio; Zambra, Marcelo; Pavez, Cristian; Clausse, Alejandro

    2006-12-04

    A gas embedded Z-pinch has been implemented using the SPEED2 generator (4.1 {mu}F equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt{approx}1013 A/s). Initial conditions to produce a gas embedded z-pinch with enhanced stability by means resistive effects and by finite Larmor radius effects were obtained and electrodes were constructed in order to obtain a double column Z-pinch and a hollow discharge. Experiments were carried out in deuterium at mega amperes currents. Current derivative and voltage signals have been obtained. In addition interferograms have been obatined using a pulse Nd-YAG laser (8ns FWMH at 532nm). Preliminary results on neutron emission were also obtained.

  3. Soft X-Ray Measurements of Z-Pinch-Driven Vacuum Hohlraums

    SciTech Connect

    Baker, K.L.; Porter, J.L.; Ruggles, L.E.; Chandler, G.A.; Deeney, Chris; Varas, M.; Moats, Ann; Struve, Ken; Torres, J.; McGurn, J.; Simpson, W.W.; Fehl, D.L.; Chrien, R.E.; Matuska, W.; Idzorek, G.C.

    1999-07-21

    This article reports the experimental characterization of a z-pinch driven-vacuum hohlraum. The authors have measured soft x-ray fluxes of 5 x 10{sup 12} W/cm{sup 2} radiating from the walls of hohlraums which are 2.4--2.5 cm in diameter by 1 cm tall. The x-ray source used to drive these hohlraums was a z-pinch consisting of a 300 wire tungsten array driven by a 2 MA, 100 ns current pulse. In this hohlraum geometry, the z-pinch x-ray source can produce energies in excess of 800 kJ and powers in excess of 100 TW to drive these hohlraums. The x-rays released in these hohlraums represent greater than a factor of 25 in energy and more than a factor of three in x-ray power over previous laboratory-driven hohlraums.

  4. Analysis of Conical Wire Array Z-Pinch Stability with a Center Wire

    SciTech Connect

    Martinez, D.; Presura, R.; Wright, S.; Plechaty, C.; Neff, S.; Wanex, L.; Ampleford, D. J.

    2009-01-21

    Adding a center wire on the axis of a conical wire array produces conditions suitable for studying shear flow stabilization of the Z-pinch. The conical wire array produces and axial plasma flow while the center wire introduces a radial variation of the axial velocity. Experiments of this array configuration were preformed on the 1 MA Zebra Z-pinch generator and showed stabilization of the kink instability when a center wire was present. Comparison with equivalent cylindrical wire arrays indicates that the shear flow stabilization plays a role in the stabilization of the kink instability.

  5. Measurement of Temperature, Density, and Particle Transport with Localized Dopants in Wire-Array Z Pinches

    SciTech Connect

    Jones, B.; Deeney, C.; McKenney, J. L.; Ampleford, D. J.; Coverdale, C. A.; LePell, P. D.; Shelton, K. P.; Safronova, A. S.; Kantsyrev, V. L.; Osborne, G.; Sotnikov, V. I.; Ivanov, V. V.; Fedin, D.; Nalajala, V.; Yilmaz, F.; Shrestha, I.

    2008-03-14

    Axially localized NaF dopants are coated onto Al cylindrical wire arrays in order to act as spectroscopic tracers in the stagnated z-pinch plasma. Non-local-thermodynamic-equilibrium kinetic models fit to Na K-shell lines provide an independent measurement of the density and temperature that is consistent with spectroscopic analysis of K-shell emissions from Al and an alloyed Mg dopant. Axial transport of the Na dopant is observed, enabling quantitative study of instabilities in dense z-pinch plasmas.

  6. Efficient neutron production from a novel configuration of deuterium gas-puff z-pinch.

    PubMed

    Klir, D; Kubes, P; Rezac, K; Cikhardt, J; Kravarik, J; Sila, O; Shishlov, A V; Kovalchuk, B M; Ratakhin, N A; Kokshenev, V A; Labetsky, A Yu; Cherdizov, R K; Fursov, F I; Kurmaev, N E; Dudkin, G N; Nechaev, B A; Padalko, V N; Orcikova, H; Turek, K

    2014-03-01

    A novel configuration of a deuterium z pinch has been used to generate fusion neutrons. Injecting an outer hollow cylindrical plasma shell around an inner deuterium gas puff, neutron yields from DD reactions reached Y(n)=(2.9 ± 0.3) × 10(12) at 700 ns implosion time and 2.7 MA current. Such a neutron yield means a tenfold increase in comparison with previous deuterium gas puff experiments at the same current generator. The increase of beam-target yields was obtained by a larger amount of current assembled on the z-pinch axis, and subsequently by higher induced voltage and higher energies of deuterons. A stack of CR-39 track detectors on the z-pinch axis showed hydrogen ions up to 38 MeV. Maximum neutron energies of 15 and 22 MeV were observed by radial and axial time-of-flight detectors, respectively. The number of DD neutrons per one joule of stored plasma energy approached 5 × 10(7). This implies that deuterium gas puff z pinches belong to the most efficient plasma-based sources of DD neutrons.

  7. Deuteron Acceleration and Fusion Neutron Production in Z-pinch plasmas

    SciTech Connect

    Klir, D.; Kravarik, J.; Kubes, P.; Rezac, K.; Ananeev, S. S.; Bakshaev, Yu. L.; Blinov, P. I.; Chernenko, A. S.; Kazakov, E. D.; Korolev, V. D.; Ustroev, G. I.

    2009-01-21

    Fusion neutron measurements were carried out on the S-300 generator (Kurchatov Institute, Moscow). We tried deuterated fibers, various types of wire arrays imploding onto a deuterated fiber, and deuterium gas puffs as Z-pinch loads. On the current level of 2 MA, the peak neutron yield of 10{sup 10} was achieved with a deuterium gas-puff. The neutron and deuteron energy spectra were quite similar in various types of Z-pinch configurations. The broad width of radial neutron spectra implied a high radial component of deuteron velocity. On the basis of neutron measurements, we concluded that neutron production mechanism is connected with the study of plasma voltage. It means that the acceleration of fast deuterons is not a secondary process but it reflects the global dynamics of Z-pinch plasmas. For this reason it is useful to add deuterium as a 'tracer' in Z-pinch loads more often. For instance, it seems attractive to prepare wire-arrays from deuterated metal wires such as Pd.

  8. UV Laser Diagnostics of the 1-MA Z-pinch Plasmas

    SciTech Connect

    Altemara, S. D.; Ivanov, V. V.; Astanovitskiy, A. L.; Haboub, A.

    2009-01-21

    The 532 nm laser diagnostic set at the Zebra generator shows the details of the ablation and stagnation phases in cylindrical, planar, and star-like wire arrays but it cannot show the structure of the stagnated z-pinch and the implosion in small diameter loads, 1-3 mm in diameter. The absorption increment and the refraction angle of the 532 nm laser, when passing through the plasma, are too great to obtain quality images. An ultraviolet probing beam at the wavelength of 266 nm was developed to study small-diameter loads and to investigate the structure of the 1-MA z-pinch. The UV radiation has a much smaller absorption increment and refraction angles in plasmas than the 532 nm light and allows for better imaging of the z-pinch plasmas. Estimates showed that UV probing would be able to probe the high-density z-pinch plasma in experiments on the Zebra generator, and the early results of UV probing on the Zebra generator have shown promise.

  9. MHRDRing Z-Pinches and Related Geometries: Four Decades of Computational Modeling Using Still Unconventional Methods

    SciTech Connect

    Lindemuth, Irvin R.

    2009-01-21

    For approximately four decades, Z-pinches and related geometries have been computationally modeled using unique Alternating Direction Implicit (ADI) numerical methods. Computational results have provided illuminating and often provocative interpretations of experimental results. A number of past and continuing applications are reviewed and discussed.

  10. Magnetic Rayleigh-Taylor instability mitigation in large-diameter gas puff Z-pinch implosions

    SciTech Connect

    Qi, N.; Sze, H.; Failor, B. H.; Banister, J.; Levine, J. S.; Riordan, J. C.; Steen, P.; Sincerny, P.; Lojewski, D.

    2008-02-15

    Recently, a new approach for efficiently generating K-shell x-rays in large-diameter, long-implosion time, structured argon gas Z-pinches has been demonstrated based on a 'pusher-stabilizer-radiator' model. In this paper, direct observations of the Rayleigh-Taylor instability mitigation of a 12-cm diameter, 200-ns implosion time argon Z-pinch using a laser shearing interferometer (LSI) and a laser wavefront analyzer (LWA) are presented. Using a zero-dimensional snowplow model, the imploding plasma trajectories are calculated with the driver current waveforms and the initial mass distributions measured using the planar laser induced fluorescence method. From the LSI and LWA images, the plasma density and trajectory during the implosion are measured. The measured trajectory agrees with the snowplow calculations. The suppression of hydromagnetic instabilities in the ''pusher-stabilizer-radiator'' structured loads, leading to a high-compression ratio, high-yield Z-pinch, is discussed. For comparison, the LSI and LWA images of an alternative load (without stabilizer) show the evolution of a highly unstable Z-pinch.

  11. O-d energetics scaling models for Z-pinch-driven hohlraums

    SciTech Connect

    CUNEO,MICHAEL E.; VESEY,ROGER A.; HAMMER,J.H.; PORTER,JOHN L.

    2000-06-08

    Wire array Z-pinches on the Z accelerator provide the most intense laboratory source of soft x-rays in the world. The unique combination of a highly-Planckian radiation source with high x-ray production efficiency (15% wall plug), large x-ray powers and energies ( >150 TW, {ge}1 MJ in 7 ns), large characteristic hohlraum volumes (0.5 to >10 cm{sup 3}), and long pulse-lengths (5 to 20 ns) may make Z-pinches a good match to the requirements for driving high-yield scale ICF capsules with adequate radiation symmetry and margin. The Z-pinch driven hohlraum approach of Hammer and Porter [Phys.Plasmas, 6, 2129(1999)] may provide a conservative and robust solution to the requirements for high yield, and is currently being studied on the Z accelerator. This paper describes a multiple region, 0-d hohlraum energetic model for Z-pinch driven hohlraums in four configurations. The authors observe consistency between the models and the measured x-ray powers and hohlraum wall temperatures to within {+-}20% in flux, for the four configurations.

  12. Design of the Fusion Z-Pinch Experiment - FuZE

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; McLean, H. S.; Nelson, B. A.; Golingo, R. P.; Schmidt, A.; Claveau, E. L.

    2015-11-01

    Based on the successful results of the sheared flow stabilized (SFS) Z-pinch from ZaP and ZaP-HD, a new experiment FuZE is designed to scale the plasma performance to fusion conditions. The SFS Z-pinch is immune to the instabilities that plague the conventional Z-pinch yet maintains the same favorable radial scaling. The plasma density and temperature increase rapidly with decreasing plasma radius, which naturally leads to a compact configuration at fusion conditions. The SFS Z-pinch is being investigated as a novel approach to a compact fusion device in a new collaborative ARPA-E ALPHA project with the University of Washington and Lawrence Livermore National Laboratory. The project includes an experimental effort coupled with high-fidelity physics modeling using kinetic and fluid simulations. Along with scaling law analysis, computational and experimental results that have informed the design and development of the FuZE apparatus are presented. This work is supported by an award from US ARPA-E.

  13. A Multiple Z-Pinch Configuration for the Generation of High-Density, Magnetized Plasmas

    NASA Astrophysics Data System (ADS)

    Tarditi, Alfonso G.

    2015-11-01

    The z-pinch is arguably the most straightforward and economical approach for the generation and confinement of hot plasmas, with a long history of theoretical investigations and experimental developments. While most of the past studies were focused on countering the natural tendency of z-pinches to develop instabilities, this study attempts to take advantage of those unstable regimes to form a quasi-stable plasma, with higher density and temperature, possibly of interest for a fusion reactor concept. For this purpose, a configuration with four z-pinch discharges, with axis parallel to each other and symmetrically positioned, is considered. Electrodes for the generation of the discharges and magnetic coils are arranged to favor the formation of concave discharge patterns. The mutual attraction from the co-streaming discharge currents enhances this pattern, leading to bent plasma streams, all nearing towards the axis. This configuration is intended to excite and sustain a ``kink'' unstable mode for each z-pinch, eventually producing either plasmoid structures, detached from each discharge, or sustained kink patterns: both these cases appear to lead to plasmas merging in the central region. The feasibility of this approach in creating a higher density, hotter, meta-stable plasma regime is investigated computationally, addressing both the kink excitation phase and the dynamics of the converging plasma columns.

  14. Efficient Neutron Production from a Novel Configuration of Deuterium Gas-Puff Z-Pinch

    NASA Astrophysics Data System (ADS)

    Klir, D.; Kubes, P.; Rezac, K.; Cikhardt, J.; Kravarik, J.; Sila, O.; Shishlov, A. V.; Kovalchuk, B. M.; Ratakhin, N. A.; Kokshenev, V. A.; Labetsky, A. Yu.; Cherdizov, R. K.; Fursov, F. I.; Kurmaev, N. E.; Dudkin, G. N.; Nechaev, B. A.; Padalko, V. N.; Orcikova, H.; Turek, K.

    2014-03-01

    A novel configuration of a deuterium z pinch has been used to generate fusion neutrons. Injecting an outer hollow cylindrical plasma shell around an inner deuterium gas puff, neutron yields from DD reactions reached Yn=(2.9±0.3)×1012 at 700 ns implosion time and 2.7 MA current. Such a neutron yield means a tenfold increase in comparison with previous deuterium gas puff experiments at the same current generator. The increase of beam-target yields was obtained by a larger amount of current assembled on the z-pinch axis, and subsequently by higher induced voltage and higher energies of deuterons. A stack of CR-39 track detectors on the z-pinch axis showed hydrogen ions up to 38 MeV. Maximum neutron energies of 15 and 22 MeV were observed by radial and axial time-of-flight detectors, respectively. The number of DD neutrons per one joule of stored plasma energy approached 5×107. This implies that deuterium gas puff z pinches belong to the most efficient plasma-based sources of DD neutrons.

  15. Los Alamos compact toroid, fast-liner, and high-density Z-pinch programs

    SciTech Connect

    Linford, R.K.; Sherwood, A.R.; Hammel, J.E.

    1981-03-01

    The Compact Toroid (CT) and High Density Z-Pinch (HDZP) are two of the plasma configurations presently being studied at Los Alamos. The purpose of these two programs, plus the recently terminated (May 1979) Fast Liner (FL) program, is summarized in this section along with a brief description of the experimental facilities. The remaining sections summarize the recent results and the experimental status.

  16. Plasma channel and Z-pinch dynamics for heavy ion transport

    SciTech Connect

    Ponce-Marquez, David

    2002-07-09

    A self stabilized, free standing, z-pinch plasma channel has been proposed to deliver the high intensity heavy ion beam from the end of a driver to the fuel target in a heavy ion inertial fusion power plant. The z-pinch relaxes emittance and energy spread requirements requiring a lower cost driver. A z-pinch transport would reduce the number of beam entry port holes to the target chamber from over a hundred to four as compared to neutralized ballistic focusing thus reducing the driver hardware exposure to neutron flux. Experiments where a double pulse discharge technique is used, z-pinch plasma channels with enhanced stability are achieved. Typical parameters are 7 kV pre-pulse discharge and 30 kV main bank discharge with 50 kA of channel current in a 7 torr background gas atmosphere. This work is an experimental study of these plasma channels examining the relevant physics necessary to understand and model such plasmas. Laser diagnostics measured the dynamical properties of neutrals and plasma. Schlieren and phase contrast techniques probe the pre-pulse gas dynamics and infrared interferometry and faraday effect polarimetry are used on the z-pinch to study its electron density and current distribution. Stability and repeatability of the z-pinch depend on the initial conditions set by the pre-pulse. Results show that the z-pinch channel is wall stabilized by an on-axis gas density depression created by the pre-pulse through hydrodynamic expansion where the ratio of the initial gas density to the final gas density is > 10/1. The low on-axis density favors avalanching along the desired path for the main bank discharge. Pinch time is around 2 s from the main bank discharge initiation with a FWHM of {approx} 2 cm. Results also show that typical main bank discharge plasma densities reach 10{sup 17} cm{sup -3} peak on axis for a 30 kV, 7 torr gas nitrogen discharge. Current rise time is limited by the circuit-channel inductance with the highest contribution to the

  17. Recent advances in theoretical and numerical studies of wire array Z-pinch in the IAPCM

    SciTech Connect

    Ding, Ning Zhang, Yang Xiao, Delong Wu, Jiming Huang, Jun Yin, Li Sun, Shunkai Xue, Chuang Dai, Zihuan Ning, Cheng Shu, Xiaojian Wang, Jianguo Li, Hua

    2014-12-15

    Fast Z-pinch has produced the most powerful X-ray radiation source in laboratory and also shows the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. A typical wire array Z-pinch process has three phases: wire plasma formation and ablation, implosion and the MRT instability development, stagnation and radiation. A mass injection model with azimuthal modulation coefficient is used to describe the wire initiation, and the dynamics of ablated plasmas of wire-array Z-pinches in (r, θ) geometry is numerically studied. In the implosion phase, a two-dimensional(r, z) three temperature radiation MHD code MARED has been developed to investigate the development of the Magneto-Rayleigh-Taylor(MRT) instability. We also analyze the implosion modes of nested wire-array and find that the inner wire-array is hardly affected before the impaction of the outer wire-array. While the plasma accelerated to high speed in the implosion stage stagnates on the axis, abundant x-ray radiation is produced. The energy spectrum of the radiation and the production mechanism are investigated. The computational x-ray pulse shows a reasonable agreement with the experimental result. We also suggest that using alloyed wire-arrays can increase multi-keV K-shell yield by decreasing the opacity of K-shell lines. In addition, we use a detailed circuit model to study the energy coupling between the generator and the Z-pinch implosion. Recently, we are concentrating on the problems of Z-pinch driven ICF, such as dynamic hohlraum and capsule implosions. Our numerical investigations on the interaction of wire-array Z-pinches on foam convertors show qualitative agreements with experimental results on the “Qiangguang I” facility. An integrated two-dimensional simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire

  18. Recent advances in theoretical and numerical studies of wire array Z-pinch in the IAPCM

    NASA Astrophysics Data System (ADS)

    Ding, Ning; Zhang, Yang; Xiao, Delong; Wu, Jiming; Huang, Jun; Yin, Li; Sun, Shunkai; Xue, Chuang; Dai, Zihuan; Ning, Cheng; Shu, Xiaojian; Wang, Jianguo; Li, Hua

    2014-12-01

    Fast Z-pinch has produced the most powerful X-ray radiation source in laboratory and also shows the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. A typical wire array Z-pinch process has three phases: wire plasma formation and ablation, implosion and the MRT instability development, stagnation and radiation. A mass injection model with azimuthal modulation coefficient is used to describe the wire initiation, and the dynamics of ablated plasmas of wire-array Z-pinches in (r, θ) geometry is numerically studied. In the implosion phase, a two-dimensional(r, z) three temperature radiation MHD code MARED has been developed to investigate the development of the Magneto-Rayleigh-Taylor(MRT) instability. We also analyze the implosion modes of nested wire-array and find that the inner wire-array is hardly affected before the impaction of the outer wire-array. While the plasma accelerated to high speed in the implosion stage stagnates on the axis, abundant x-ray radiation is produced. The energy spectrum of the radiation and the production mechanism are investigated. The computational x-ray pulse shows a reasonable agreement with the experimental result. We also suggest that using alloyed wire-arrays can increase multi-keV K-shell yield by decreasing the opacity of K-shell lines. In addition, we use a detailed circuit model to study the energy coupling between the generator and the Z-pinch implosion. Recently, we are concentrating on the problems of Z-pinch driven ICF, such as dynamic hohlraum and capsule implosions. Our numerical investigations on the interaction of wire-array Z-pinches on foam convertors show qualitative agreements with experimental results on the "Qiangguang I" facility. An integrated two-dimensional simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire

  19. Numerical simulation of fiber and wire array Z-pinches with Trac-II

    SciTech Connect

    Reisman, D

    1998-09-01

    Trac-II is a two dimensional axisymmetric resistive MHD code. It simulates all three spatial components (r, z, φ) of the magnetic field and fluid velocity vectors, and the plasma is treated as a single fluid with two temperatures (Te,Ti). In addition, it can optionally include a self-consistent external circuit. Recent modifications to the code include the addition of the 3-T radiation model, a 4-phase (solid-liquid-vapor-plasma) equation of state model (QEOS), a 4-phase electrical/thermal conductivity model, and an implicit solution of poloidal Bz,Br) magnetic field diffusion. These changes permit a detailed study of fiber and wire array Z-pinches. Specifically, Trac-II is used to study the wire array Z-pinch at the PBFA-Z pulse power generator at Sandia National Laboratory. First, in 1-D we examine the behavior of a single wire in the Z-pinch. Then, using these results as initial radial conditions in 2-D, we investigate the dynamics of wire array configurations in the r-z and r-θ plane. In the r-z plane we examine the growth of the m=0 or "sausage" instability in single wires within the array. In the r-θ plane we examine the merging behavior between neighboring wires. Special emphasis is placed on trying to explain how instability growth affects the performance of the Z-pinch. Lastly, we introduce Trac-III, a 3-D MHD code, and illustrate the m=1 or "kink" instability. We also discuss how Trac-III can be modified to simulate the wire array Z-pinch.

  20. Diagnosing x-ray power and energy of tungsten wire array z-pinch with a flat spectral response x-ray diode.

    PubMed

    Wang, Kun-lun; Ren, Xiao-dong; Huang, Xian-bin; Zhang, Si-qun; Zhou, Shao-tong; Dan, Jia-kun; Li, Jing; Xu, Qiang; Ouyang, Kai; Cai, Hong-chun; Wei, Bing; Ji, Ce; Feng, Shu-ping; Wang, Meng; Xie, Wei-ping; Deng, Jian-jun

    2015-11-01

    Fast z-pinch is a very efficient way of converting electromagnetic energy to radiation. With an 8-10 MA current on primary test stand facility, about 1 MJ electromagnetic energy is delivered to vacuum chamber, which heats z-pinch plasma to radiate soft x-ray. To develop a pulsed high power x-ray source, we studied the applicability of diagnosing x-ray power from tungsten wire array z-pinch with a flat spectral response x-ray diode (FSR-XRD). The detector was originally developed to diagnose radiation of a hohlraum in SG-III prototype laser facility. It utilized a gold cathode XRD and a specially configured compound gold filter to yield a nearly flat spectral response in photon energy range of 0.1-4 keV. In practice, it was critical to avoid surface contamination of gold cathode. It is illustrated that an exposure of an XRD to multiple shots caused a significant change of response. Thus, in diagnosing x-ray power and energy, we used each XRD in only one shot after calibration. In a shot serial, output of FSR-XRD was compared with output of a nickel bolometer. In these shots, the outputs agreed with each other within their uncertainties which were about 12% for FSR-XRD and about 15% for bolometer. Moreover, the ratios between the FSR-XRD and the bolometer among different shots were explored. In 8 shots, the standard deviation of the ratio was 6%. It is comparable to XRD response change of 7%. PMID:26628136

  1. Diagnosing x-ray power and energy of tungsten wire array z-pinch with a flat spectral response x-ray diode

    SciTech Connect

    Wang, Kun-lun; Ren, Xiao-dong; Huang, Xian-bin Zhang, Si-qun; Zhou, Shao-tong; Dan, Jia-kun; Li, Jing; Xu, Qiang; Ouyang, Kai; Cai, Hong-chun; Wei, Bing; Ji, Ce; Feng, Shu-ping; Wang, Meng; Xie, Wei-ping; Deng, Jian-jun

    2015-11-15

    Fast z-pinch is a very efficient way of converting electromagnetic energy to radiation. With an 8-10 MA current on primary test stand facility, about 1 MJ electromagnetic energy is delivered to vacuum chamber, which heats z-pinch plasma to radiate soft x-ray. To develop a pulsed high power x-ray source, we studied the applicability of diagnosing x-ray power from tungsten wire array z-pinch with a flat spectral response x-ray diode (FSR-XRD). The detector was originally developed to diagnose radiation of a hohlraum in SG-III prototype laser facility. It utilized a gold cathode XRD and a specially configured compound gold filter to yield a nearly flat spectral response in photon energy range of 0.1-4 keV. In practice, it was critical to avoid surface contamination of gold cathode. It is illustrated that an exposure of an XRD to multiple shots caused a significant change of response. Thus, in diagnosing x-ray power and energy, we used each XRD in only one shot after calibration. In a shot serial, output of FSR-XRD was compared with output of a nickel bolometer. In these shots, the outputs agreed with each other within their uncertainties which were about 12% for FSR-XRD and about 15% for bolometer. Moreover, the ratios between the FSR-XRD and the bolometer among different shots were explored. In 8 shots, the standard deviation of the ratio was 6%. It is comparable to XRD response change of 7%.

  2. Reliability comparison of GaAlAs/GaAs and aluminum-free high-power laser diodes

    NASA Astrophysics Data System (ADS)

    Pendse, D. R.; Chin, Aland K.; Dabkowski, Ferdynand P.; Clausen, Edward M., Jr.

    1998-08-01

    Aluminum-free laser diodes are InGaAsP/GaAs devices whose epitaxial layers do not contain aluminum. Studies comparing the GaAslAs/GaAs and InGaAsP/GaAs high power laser diodes allegedly indicate that aluminum-free lasers are more reliable due to a reduction of dark-line defects, sudden failures, and gradual degradation. The improved reliability of aluminum-free lasers is presumed to result from the elimination of oxidation of the aluminum-containing epitaxial layers of the laser facets. In this presentation, the performance and reliability of GaAlAs/GaAs and InGaAsP/GaAs high power laser diodes will be reviewed and compared. The present data shows that high reliable GaAlAs/GaAs lasers can be produced with good manufacturing practices.

  3. Effect of soft metal gasket contacts on contact resistance, energy deposition, and plasma expansion profile in a wire array Z pinch

    SciTech Connect

    Gomez, M. R.; Zier, J. C.; Gilgenbach, R. M.; French, D. M.; Tang, W.; Lau, Y. Y.

    2008-09-15

    Soft metal gaskets (indium and silver) were used to reduce contact resistance between the wire and the electrode in an aluminum wire Z pinch by more than an order of magnitude over the best weighted contact case. Clamping a gasket over a Z-pinch wire compresses the wire to the electrode with a greater normal force than possible with wire weights. Average contact resistance was reduced from the range of 100-3000 {omega} (depending on wire weight mass) to 1-10 {omega} with soft metal gaskets. Single wire experiments (13 {mu}m Al 5056) on a 16 kA, 100 kV Marx bank showed an increase in light emission (97%) and emission volume (100%) of the plasma for the reduced contact resistance cases. The measured increases in plasma volume and light emission indicate greater energy deposition in the ablated wire. Additionally, dual-wire experiments showed plasma edge effects were significantly decreased in the soft metal gasket contact case. The average height of the edge effects was reduced by 51% and the width of the edge effects was increased by 40%, thus the gasket contact case provided greater axial uniformity in the plasma expansion profile of an individual wire.

  4. Effect of soft metal gasket contacts on contact resistance, energy deposition, and plasma expansion profile in a wire array Z pinch.

    PubMed

    Gomez, M R; Zier, J C; Gilgenbach, R M; French, D M; Tang, W; Lau, Y Y

    2008-09-01

    Soft metal gaskets (indium and silver) were used to reduce contact resistance between the wire and the electrode in an aluminum wire Z pinch by more than an order of magnitude over the best weighted contact case. Clamping a gasket over a Z-pinch wire compresses the wire to the electrode with a greater normal force than possible with wire weights. Average contact resistance was reduced from the range of 100-3000 Omega (depending on wire weight mass) to 1-10 Omega with soft metal gaskets. Single wire experiments (13 microm Al 5056) on a 16 kA, 100 kV Marx bank showed an increase in light emission (97%) and emission volume (100%) of the plasma for the reduced contact resistance cases. The measured increases in plasma volume and light emission indicate greater energy deposition in the ablated wire. Additionally, dual-wire experiments showed plasma edge effects were significantly decreased in the soft metal gasket contact case. The average height of the edge effects was reduced by 51% and the width of the edge effects was increased by 40%, thus the gasket contact case provided greater axial uniformity in the plasma expansion profile of an individual wire.

  5. Measurement of emission diameter as a function of time on foam z- pinch plasmas

    SciTech Connect

    Lazier, S.E.; Barber, T.L.; Derzon, M.S.; Kellogg, J.W.

    1996-05-14

    We have developed a streaked imaging capability to make time-resolved measurements of the emission size for low density foam z-pinches. By lens coupling visible emission from the z-pinch target to an array of fiber optics we obtained the emission profile in the visible as a function of time with radial resolution of 300 {mu}m. To measure the emission at temperatures greater than {approx}40 eV the source was slit-imaged or pin-hole imaged onto an x-ray filtered scintillator. Non-uniformities in both visible and x-ray emission were observed. We describe the diagnostics, the image unfold process, and results from the instrument for both visible and x-ray measurements.

  6. Exploring Ways to Improve Predictive Capability of Z-Pinch Calculations

    SciTech Connect

    Matuska, W.; Aubrey, J.; Bowers, R.; Lee, H.; Peterson, D.; Deeney, C.; Derzon, M.; Nash, T.

    1998-10-19

    For some time 2-dimensional RMHD (radiation magneto-hydrodynamic) calculations of radiating z-pinches have been made to agree with integral data (current wave form, yield and power). For these calculations, the agreement with detailed data, such as time-resolved x-ray images, is generally not as good. Correctly modeling the physics of z-pinches, including detailed data, is needed to have true predictive capability. To address this problem, the authors first determine which integral data are most sensitive to the details in the models. With this information, they investigate aspects of the pinch, to which the data is sensitive, using non-standard techniques. For example, the pinch is calculated in (x,y)-geometry to investigate how a non-symmetric implosion affects the simulated data.

  7. Study of the stability of Z-pinch implosions with different initial density profiles

    SciTech Connect

    Rousskikh, A. G.; Zhigalin, A. S.; Labetskaya, N. A.; Chaikovsky, S. A.; Yushkov, G. Yu.; Oreshkin, V. I.; Batrakov, A. V.; Baksht, R. B.

    2014-05-15

    Stability of metal-puff Z pinches was studied experimentally. Experiments were carried out on a facility producing a load current up to 450 kA with a rise time of 450 ns. In a metal-puff Z pinch, the plasma shell is produced due to evaporation of the electrode material during the operation of a vacuum arc. In the experiment to be reported, a single-shell and a shell-on-jet pinch load with magnesium electrodes were used. Two-dimensional, 3 ns gated, visible-light images were taken at different times during the implosion. When the shell was formed from a collimated plasma flow with small radial divergence, Rayleigh–Taylor (RT) instability typical of gas-puff implosions was recorded. The RT instability was completely suppressed in a mode where the initial density distribution of the shell approached a tailored density profile [A. L. Velikovich et al., Phys. Rev. Lett. 77, 853 (1996)].

  8. Investigation of asymmetry of wire-array Z pinches at stagnation using a 4-channel laser diagnostic

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.; Anderson, A. A.

    2016-09-01

    Asymmetry of wire-array Z-pinches at stagnation was investigated using four synchronized laser beams at the wavelength of 266 nm. These beams were spaced at 45° with respect to each other, allowing a full view of the pinch from four directions. The laser pulse duration was 0.2 ns, with a <0.1 ns temporal accuracy between the four channels. Strong asymmetry was found in Z pinches produced by implosion of asymmetrical wire array loads. Anisotropy of the wire-array Z pinch arises due to the asymmetric implosion and development of plasma instabilities. Understanding the three-dimensional structure of Z-pinches is important for interpretation of data from x-ray and laser diagnostics.

  9. Control of x-ray spectrum emitted from a gas-puff Z-pinch

    SciTech Connect

    Takasugi, Keiichi; Miyamoto, Tetsu; Tatsumi, Katsuhiro; Igusa, Takehito

    1997-05-05

    The axial magnetic field is applied to an annular gas-puff z-pinch for the control of radial dynamics and x-ray emission from the pinched plasma. K-shell and L-shell radiations of Ar ions are detected separately, and only the K-shell radiation is suppressed significantly by the axial field. The radial motion of the plasma is analyzed assuming a simple circuit model. The characteristic radius of the plasma increased with increasing the axial field.

  10. Influence of induced axial magnetic field on plasma dynamics and radiative characteristics of Z pinches

    SciTech Connect

    Kantsyrev, V. L.; Esaulov, A. A.; Safronova, A. S.; Osborne, G. C.; Shrestha, I.; Weller, M. E.; Stafford, A.; Shlyaptseva, V. V.; Velikovich, A. L.; Rudakov, L. I.; Williamson, K. M.

    2011-10-15

    The influence of an induced axial magnetic field on plasma dynamics and radiative characteristics of Z pinches is investigated. An axial magnetic field was induced in a novel Z-pinch load: a double planar wire array with skewed wires (DPWAsk), which represents a planar wire array in an open magnetic configuration. The induced axial magnetic field suppressed magneto-Rayleigh-Taylor (MRT) instabilities (with m = 0 and m = 1 instability modes) in the Z-pinch plasma. The influence of the initial axial magnetic field on the structure of the plasma column at stagnation was manifested through the formation of a more uniform plasma column compared to a standard double planar wire array (DPWA) load [V. L. Kantsyrev et al., Phys. Plasmas 15, 030704 (2008)]. The DPWAsk load is characterized by suppression of MRT instabilities and by the formation of the sub-keV radiation pulse that occurs before the main x-ray peak. Gradients in plasma parameters along the cathode-anode gap were observed and analyzed for DPWAsk loads made from low atomic number Z (Al) and mid-Z (brass) wires.

  11. Z-pinch equilibrium and instability analysis with digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Ross, M. P.; Shumlak, U.; Nelson, B. A.; Golingo, R. P.; Hughes, M. C.; Claveau, E. L.; Weed, J. R.; Forbes, E. G.; Doty, S. A.; Kim, B.

    2015-11-01

    The ZaP-HD Flow Z-Pinch project generates flow shear stabilized Z-pinches, providing a platform to explore how such plasmas could scale to HEDP and fusion reactor conditions. To scale up the plasma's density and temperature, it must be compressed to a smaller size making measurements more difficult. Digital holographic interferometry (DHI) employing a pulsed Nd:YAG laser and consumer DSLR camera can spatially resolve the plasma's electron density. The Fresnel reconstruction method allows expedient numerical data reconstruction. Obtaining electron density radial profiles relies on applying an Abel inversion to convert measured line-integrated density, and the inversion process provides an independent measure of plasma symmetry. Entire Z-pinch equilibria (n, P, T, and B profiles) can be computed by applying physical models to the density data. Tracking the time evolution of pressure and density can reveal the presence of non-adiabatic heating mechanisms. Imaging the size scales of instabilities enables relative measures of viscosity at different positions and times. Error estimation of measured density profiles is presented along with observed asymmetric instabilities. This work is supported by grants from the U.S. Department of Energy and the U.S. National Nuclear Security Administration.

  12. Application of 2-D simulations to hollow z-pinch implosions

    SciTech Connect

    Peterson, D.L.; Bowers, R.L.; Brownell, J.H.

    1997-12-01

    The application of simulations of z-pinch implosions should have at least two goals: first, to properly model the most important physical processes occurring in the pinch allowing for a better understanding of the experiments and second, provide a design capability for future experiments. Beginning with experiments fielded at Los Alamos on the Pegasus 1 and Pegasus 2 capacitor banks, the authors have developed a methodology for simulating hollow z-pinches in two dimensions which has reproduced important features of the measured experimental current drive, spectrum, radiation pulse shape, peak power and total radiated energy. This methodology employs essentially one free parameter, the initial level of the random density perturbations imposed at the beginning of the 2-D simulation, but in general no adjustments to other parameters are required. Currently the authors are applying this capability to the analysis of recent Saturn and PBFA-Z experiments. The code results provide insight into the nature of the pinch plasma prior to arrival on-axis, during thermalization and development after peak pinch time. Among other things, the simulation results provide an explanation for the production of larger amounts of radiated energy than would be expected from a simple slug-model kinetic energy analysis and the appearance of multiple peaks in the radiation power. The 2-D modeling has also been applied to the analysis of Saturn dynamic hohlraum experiments and is being used in the design of this and other Z-Pinch applications on PBFA-Z.

  13. Study of magnetic fields and current in the Z pinch at stagnation

    SciTech Connect

    Ivanov, V. V.; Anderson, A. A.; Astanovitskiy, A. L.; Nalajala, V.; Dmitriev, O.; Papp, D.

    2015-09-15

    The structure of magnetic fields in wire-array Z pinches at stagnation was studied using a Faraday rotation diagnostic at the wavelength of 266 nm. The electron plasma density and the Faraday rotation angle in plasma were calculated from images of the three-channel polarimeter. The magnetic field was reconstructed with Abel transform, and the current was estimated using a simple model. Several shots with wire-array Z pinches at 0.5–1.5 MA were analyzed. The strength of the magnetic field measured in plasma of the stagnated pinch was in the range of 1–2 MG. The magnetic field and current profile in plasma near the neck on the pinch were reconstructed, and the size of the current-carrying plasma was estimated. It was found that current flowed in the large-size trailing plasma near the dense neck. Measurements of the magnetic field near the bulge on the pinch also showed current in trailing plasma. A distribution of current in the large-size trailing plasma can prevent the formation of multi-MG fields in the Z pinch.

  14. Study of magnetic fields and current in the Z pinch at stagnation

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.; Anderson, A. A.; Papp, D.; Astanovitskiy, A. L.; Nalajala, V.; Dmitriev, O.

    2015-09-01

    The structure of magnetic fields in wire-array Z pinches at stagnation was studied using a Faraday rotation diagnostic at the wavelength of 266 nm. The electron plasma density and the Faraday rotation angle in plasma were calculated from images of the three-channel polarimeter. The magnetic field was reconstructed with Abel transform, and the current was estimated using a simple model. Several shots with wire-array Z pinches at 0.5-1.5 MA were analyzed. The strength of the magnetic field measured in plasma of the stagnated pinch was in the range of 1-2 MG. The magnetic field and current profile in plasma near the neck on the pinch were reconstructed, and the size of the current-carrying plasma was estimated. It was found that current flowed in the large-size trailing plasma near the dense neck. Measurements of the magnetic field near the bulge on the pinch also showed current in trailing plasma. A distribution of current in the large-size trailing plasma can prevent the formation of multi-MG fields in the Z pinch.

  15. Preliminary experimental results of tungsten wire-array Z-pinches on primary test stand

    SciTech Connect

    Huang, Xian-Bin; Zhou, Shao-Tong; Dan, Jia-Kun; Ren, Xiao-Dong Wang, Kun-Lun; Zhang, Si-Qun; Li, Jing; Xu, Qiang; Cai, Hong-Chun; Duan, Shu-Chao; Ouyang, Kai; Chen, Guang-Hua; Ji, Ce; Wei, Bing; Feng, Shu-Ping; Wang, Meng; Xie, Wei-Ping; Deng, Jian-Jun; Zhou, Xiu-Wen; Yang, Yi

    2015-07-15

    The Primary Test Stand (PTS) developed at the China Academy of Engineering Physics is a 20 TW pulsed power driver, which can deliver a ∼10 MA, 70 ns rise-time (10%–90%) current to a short-circuit load and has important applications in Z-pinch driven inertial confinement fusion and high energy density physics. Preliminary results of tungsten wire-array Z-pinch experiments on PTS are presented. The load geometries investigated include 15-mm-tall cylindrical single and nested arrays with diameter ranging from 13 mm to 30 mm, consisting of 132–300 tungsten wires with 5–10 μm in diameter. Multiple diagnostics were fielded to characterize the x-ray radiation from wire-array Z pinches. The x-ray peak power (∼50 TW) and total radiated energy (∼500 kJ) were obtained from a single 20-mm-diam array with 80-ns stagnation time. The highest x-ray peak power up to 80 TW with 2.4 ns FWHM was achieved by using a nested array with 20-mm outer diameter, and the total x-ray energy from the nested array is comparable to that of single array. Implosion velocity estimated from the time-resolved image measurement exceeds 30 cm/μs. The detailed experimental results and other findings are presented and discussed.

  16. Study of micro-pinches in wire-array Z pinches

    SciTech Connect

    Ivanov, V. V.; Papp, D.; Anderson, A. A.; Talbot, B. R.; Astanovitskiy, A. L.; Nalajala, V.; Dmitriev, O.; Chittenden, J. P.; Niasse, N.; Pikuz, S. A.; Shelkovenko, T. A.

    2013-11-15

    Bright and hot areas with a high plasma density and temperature are observed in all kinds of Z pinches. We studied bright radiating spots produced by micro-pinches in cylindrical and planar wire-arrays at the 1 MA Zebra pulsed power generator using an x-ray streak camera synchronized with laser diagnostics, x-ray time-gated pinhole camera, and spectroscopy. Hot spots with extremely dense and relatively hot plasma arise during the collapse of the micro-pinches. These hot spots radiate a continuum spectrum with energy >2.5 keV. Typical micro-pinches in Al wire arrays generate x-ray bursts with durations of 0.4–1 ns in the soft x-ray range and 0.1–0.4 ns in the keV range. UV two-frame shadowgraphy shows spatial correlation of hot spots with the collapse and explosion of micro-pinches. Micro-pinches typically occur at the necks of the Z pinch, but can demonstrate a variety of parameters and different dynamics. An analysis of x-ray streak images shows that micro-pinches can generate >20% of the x-ray energy in some types of wire-array Z pinches.

  17. Radiation-Hydromagnetic Models of a Z-Pinch Implosion with an Axial Magnetic Field

    NASA Astrophysics Data System (ADS)

    Clark, R. W.; Giuliani, J. L.; Terry, R.; Davis, J.; Velikovich, A. L.

    1997-11-01

    Experimental results on a 1MA pulser suggest that axial magnetic fields can stabilize z-pinch implosions and enhance the compression ratio(S. Sorokin and S. Chaikovsky, Dense Z-Pinches, AIP Conf. Proc. 299, p.83 (1993).). The present theoretical work calculates the effects of an axial magnetic field on the plasma and field profiles in an imploding z-pinch. The initial mass configuration is an annular shell of krypton. The 1-D simulation model includes: resistive diffusion (skin effect) for both the azimuthal and axial fields, ionization dynamics, and non-LTE radiation transport. Unlike the constant pulser current of self-similar models for the screw-pinch, a transmission line is used to model the circuit of a realistic ~10MA pulser. The implosion dynamics resulting from an axial field generated by a twisted return current cage will be compared with results due to an initial field from external Helmholtz coils. The dependence of the radiative performance on compression ratio, which in turn is a function of inital field strength or cage twist, will be discussed.

  18. The microscopic Z-pinch process of current-carrying rarefied deuterium plasma shell

    SciTech Connect

    Ning, Cheng; Xue, Chuang; Li, Baiwen; Feng, Zhixing

    2015-02-15

    For insight into the microscopic mechanism of Z-pinch dynamic processes, a code of two-dimensional particle-in-cell (PIC) simulation has been developed in cylindrical coordinates. In principle, the Z-pinch of current-carrying rarefied deuterium plasma shell has been simulated by means of this code. Many results related to the microscopic processes of the Z-pinch are obtained. They include the spatio-temporal distributions of electromagnetic field, current density, forces experienced by the ions and electrons, positions and energy distributions of particles, and trailing mass and current. In radial direction, the electric and magnetic forces exerted on the electrons are comparable in magnitude, while the forces exerted on the ions are mainly the electric forces. So in the Z-pinch process, the electrons are first accelerated in Z direction and get higher velocities; then, they are driven inwards to the axis at the same time by the radial magnetic forces (i.e., Lorentz forces) of them. That causes the separations between the electrons and ions because the ion mass is much larger than the electron's, and in turn a strong electrostatic field is produced. The produced electrostatic field attracts the ions to move towards the electrons. When the electrons are driven along the radial direction to arrive at the axis, they shortly move inversely due to the static repellency among them and their tiny mass, while the ions continue to move inertially inwards, and later get into stagnation, and finally scatter outwards. Near the stagnation, the energies of the deuterium ions mostly range from 0.3 to 6 keV, while the electron energies are mostly from 5 to 35 keV. The radial components, which can contribute to the pinched plasma temperature, of the most probable energies of electron and ion at the stagnation are comparable to the Bennett equilibrium temperature (about 1 keV), and also to the highest temperatures of electron and ion obtained in one dimensional radiation

  19. Increasing the K-shell yield of line radiation in Z-pinch implosions using alloyed Al/Mg wire-arrays

    SciTech Connect

    Xiao Delong; Ding Ning; Xue Chuang; Huang Jun; Zhang Yang; Ning Cheng; Sun Shunkai

    2013-01-15

    The variation of the K-shell yield of pure aluminum wire-array Z-pinch implosions with load parameters is discussed. The mechanism and the efficiency of increasing the K-shell yield using alloyed Al/Mg wire-arrays are numerically investigated. It has been shown that the maximum K-shell yield from a pure aluminum wire-array Z-pinch implosion can be obtained at an optimal load mass for a given generator and at a fixed initial wire-array radius. This optimal load mass is determined by the load energy coupling with the generator, the capability of Z-pinch plasmas to emit the K-shell radiation, and the self absorption of K-shell lines. For different generators, the optimal load mass increases as the drive current increases, and the line absorption limits the further increase of K-shell radiation. The coupled energy per ion is likely decreasing with increased mass, so the plasma might not be able to ionize into the K-shell. Also, the ability of the plasma to radiatively cool can increase with mass, thus, making it difficult for the plasma to ionize into and remain in the K-shell during the stagnation phase of the implosion. Alloyed Al/Mg wire-arrays were thus suggested to be used to decrease the opacity of K-shell lines and to increase the overall K-shell yield. In this paper, we show that using alloyed Al/Mg wire-arrays will decrease the opacity and increase the K-shell yield remarkably if the plasma is optically thick. We will also show that the efficiency of increasing the K-shell yield with alloyed Al/Mg wire-arrays cannot increase indefinitely. The ratio of K-shell yield from an alloyed Al/Mg wire-array to that from a pure aluminum wire-array reaches a limit. For example, we show that when the mass share of magnesium is 10% then this limit is 1.2, and for a 50% mass share, the limit is 1.3.

  20. Dense Plasma Focus Z-Pinch Fully Kinetic Modeling and Ion Probe-Beam Experiments

    NASA Astrophysics Data System (ADS)

    Schmidt, Andrea

    2013-10-01

    The Z-pinch phase of a dense plasma focus (DPF) emits multiple-MeV ions on a cm-scale length, even for kJ-scale devices. The mechanisms through which these physically simple devices generate such high energy beams in a relatively short distance are not fully understood. We are exploring the mechanisms behind these large gradients using the first fully kinetic simulations of a DPF Z-pinch as well as an ion probe beam experiment in which a 4 MeV deuteron beam is injected along the z-axis of a DPF Z-pinch plasma and accelerated. Our table-top DPF has demonstrated >50 MV/m acceleration gradients during 800 J operation using a fast capacitive driver. We have now directly measured the DPF gradients and demonstrated acceleration of an injected ion beam for the first time. Our particle-in-cell simulations have successfully predicted observed DPF ion beams and neutron yield, which past fluid simulations have not reproduced. We have now experimentally measured and observed in the simulations for the first time, electric field oscillations near the lower hybrid frequency. This is suggestive that the lower hybrid drift instability, long speculated to be the cause of the anomalous plasma resistivity that produces large DPF gradients, is playing an important role. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for accelerator and neutron source applications. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.

  1. The importance of EBIT data for Z-pinch plasma diagnostics

    SciTech Connect

    Safronova, A S; Kantsyrev, V L; Neill, P; Safronova, U I; Fedin, D A; Ouart, N D; Yilmaz, M F; Osborne, G; Shrestha, I; Williamson, K; Hoppe, T; Harris, C; Beiersdorfer, P; Hansen, S

    2007-04-04

    The results from the last six years of x-ray spectroscopy and spectropolarimetry of high energy density Z-pinch plasmas complemented by experiments with the electron beam ion trap (EBIT) at the Lawrence Livermore National Laboratory (LLNL) are presented. The two topics discussed are the development of M-shell x-ray W spectroscopic diagnostics and K-shell Ti spectropolarimetry of Z-pinch plasmas. The main focus is on radiation from a specific load configuration called an 'X-pinch'. X-pinches are excellent sources for testing new spectral diagnostics and for atomic modelling because of the high density and temperature of the pinch plasmas, which scale from a few {micro}m to several mm in size. They offer a variety of load configurations, which differ in wire connections, number of wires, and wire materials. In this work the study of X-pinches with tungsten wires combined with wires from other, lower-Z materials is reported. Utilizing data produced with the LLNL EBIT at different energies of the electron beam the theoretical prediction of line positions and intensity of M-shell W spectra were tested and calibrated. Polarization-sensitive X-pinch experiments at the University of Nevada, Reno (UNR) provide experimental evidence for the existence of strong electron beams in Ti and Mo X-pinch plasmas and motivate the development of x-ray spectropolarimetry of Z-pinch plasmas. This diagnostic is based on the measurement of spectra recorded simultaneously by two spectrometers with different sensitivity to the linear polarization of the observed lines and compared with theoretical models of polarization-dependent spectra. Polarization-dependent K-shell spectra from Ti X-pinches are presented and compared with model calculations and with spectra generated by a quasi-Maxwellian electron beam at the LLNL EBIT-II electron beam ion trap.

  2. X-ray results from a modified nozzle and double gas puff z pinch

    SciTech Connect

    Chang, T.; Fisher, A.; Van Drie, A. )

    1991-03-15

    The nozzle and the anode of the UCI (University of California, Irvine) {ital z}-pinch facility were modified to study the influence of the anode-cathode geometrical structure on the stability of the pinch and the x-ray yield of the pinch. The anode was modified from a honey-comb to a hollow cylinder with a 4-cm diameter and a {similar to}3.5-mm wall thickness, placed 2 cm below the cathode. The cavity in the center of the cathode was enlarged from 6-mm diameter to 36 mm. The design of the cathode and the anode showed a marked improvement of the pinch stability over the previous design. Both zirconium and carbon-carbon nozzle were used for the Kr and Ne {ital z} pinches. After a few tens of shots the Zr nozzle was melted at the edge and the pinch degraded, while the carbon-carbon nozzle did not sustain any damage for more than 300 shots. Some shots showed the {ital di}/{ital dt} at the implosion is {similar to}5 times higher than the {ital di}/{ital dt} at the beginning of the discharge, this has never been obtained at UCI before. This ratio of the initial {ital di}/{ital dt} to pinch {ital di}/{ital dt} is a measure of the pinch quality. By serendipity it was found that double gas puff {ital z} pinch increased the hard x-ray ({gt}1 keV) output by about an order of magnitude. The nozzle was then modified to allow double puff operation. A 3.4-mm-diam hole was opened at the center of the nozzle and a plunger was inserted from the top to control the mass of the gas entering the hole. The diagnostics include {ital di}/{ital dt} coil, soft, and hard x-ray diodes. Soft and hard x-ray emission are both enhanced by the double gas puff {ital z} pinch.

  3. ALEGRA modeling of gas puff Z-pinch experiments at the ZR facility.

    SciTech Connect

    Coleman, P. L.; Flicker, Dawn G.; Coverdale, Christine Anne; Kueny, Christopher Shane; Krishnan, Mahadevan

    2010-11-01

    Gas puff z-pinch experiments have been proposed for the refurbished Z (ZR) facility for CY2011. Previous gas puff experiments [Coverdale et. al., Phys. Plasmas 14, 056309, 2007] on pre-refurbishment Z established a world record for laboratory fusion neutron yield. New experiments would establish ZR gas puff capability for x-ray and neutron production and could surpass previous yields. We present validation of ALEGRA simulations against previous Z experiments including X-ray and neutron yield, modeling of gas puff implosion dynamics for new gas puff nozzle designs, and predictions of X-ray and neutron yields for the proposed gas puff experiments.

  4. The inverse skin effect in the Z-pinch and plasma focus

    NASA Astrophysics Data System (ADS)

    Usenko, P. L.; Gaganov, V. V.

    2016-08-01

    The inverse skin effect and its influence on the dynamics of high-current Z-pinch and plasma focus discharges in deuterium are analyzed. It is shown that the second compression responsible for the major fraction of the neutron yield can be interpreted as a result of the inverse skin effect resulting in the axial concentration of the longitudinal current density and the appearance of a reversed current in the outer layers of plasma pinches. Possible conditions leading to the enhancement of the inverse skin effect and accessible for experimental verification by modern diagnostics are formulated.

  5. Use of spherically bent crystals to diagnose wire array z pinches

    SciTech Connect

    Shelkovenko, T.A.; Pikuz, S.A.; Hammer, D.A.; Ampleford, D.J.; Bland, S.N.; Bott, S.C.; Chittenden, J.P.; Lebedev, S.V.

    2004-10-01

    Spherically bent mica and quartz crystals have provided time-integrated spectra and monochromatic images in self-radiation of wire array z-pinch implosions on the MAGPIE generator (1 MA, 240 ns) at Imperial College. Diagnostics based on spherically bent crystals offer higher efficiencies than those based on flat or convex dispersion elements, allowing positioning far from the pinch with good debris shielding. A mica crystal spectrometer produced an image of the pinch in each emission line with about 100 {mu}m axial resolution. Combining the results of monochromatic imaging and spectra confirmed the presence of bright spots, probably generated by energetic electrons inside the pinch.

  6. On the possibility of neutron generation in an imploding TiD{sub 2} puff Z pinch

    SciTech Connect

    Baksht, Rina B.; Oreshkin, Vladimir I.; Rousskikh, Alexander G.

    2013-08-15

    Simulation of implosion of a TiD{sub 2} puff Z pinch is reported. The Z pinch is supposed to be produced by the plasma flow generated by a vacuum arc, as described by Rousskikh et al.[Phys. Plasmas 18, 092707 (2011)]. To simulate the implosion, a one-dimensional two-temperature radiative magnetohydrodynamics code was used. The simulation has shown that neutrons are generated during the implosion of a TiD{sub 2} puff Z pinch due to thermalization of the pinch plasma stagnated on axis. It has been shown that the necessary condition for neutron generation is that the ion temperature must be substantially higher than the electron temperature. For a pinch current of 1 MA, the predicted yield of 'thermal' neutrons is 2.5 × 10{sup 9} neutrons/shot.

  7. A high impedance mega-ampere generator for fiber z-pinch experiments

    NASA Astrophysics Data System (ADS)

    Mitchell, I. H.; Bayley, J. M.; Chittenden, J. P.; Worley, J. F.; Dangor, A. E.; Haines, M. G.; Choi, P.

    1996-04-01

    At Imperial College a mega-ampere generator for plasma implosion experiments has been designed, built, and commissioned. With a final line impedance of 1.25 Ω this terawatt class generator has been designed primarily to drive a maximum current of 1.8 MA with a rise time of 150 ns into high inductance z-pinch loads of interest to radiative collapse studies. This article describes the design and tests of the generator which has a novel configuration of lines and a new design of a magnetically insulated transmission line (MITL). In summary, the generator consists of four Marx generators each of the Hermes III type (2.4 MV, 84 kJ), each connected to 5 Ω pulse forming lines and trigatron gas switches. The power is fed into the matched 1.25 Ω vertical transfer line which feeds a diode stack and a short conical MITL in vacuum which concentrates the power into the z-pinch load. At 80% charge a current rising to 1.4 MA in 150 ns has been measured in a 15 nH inductive short. Similar results are obtained when using a plasma load.

  8. A short-pulse mode for the SPHINX LTD Z-pinch driver

    NASA Astrophysics Data System (ADS)

    D'Almeida, Thierry; Lassalle, Francis; Zucchini, Frederic; Loyen, Arnaud; Morell, Alain; Chuvatin, Alexander

    2015-11-01

    The SPHINX machine is a 6MA, 1 μs, LTD Z-pinch driver at CEA Gramat (France) and primarily used for studying radiation effects. Different power amplification concepts were examined in order to reduce the current rise time without modifying the generator discharge scheme, including the Dynamic Load Current Multiplier (DLCM) proposed by Chuvatin. A DLCM device, capable of shaping the current pulse without reducing the rise time, was developed at CEA. This device proved valuable for isentropic compression experiments in cylindrical geometry. Recently, we achieved a short pulse operation mode by inserting a vacuum closing switch between the DLCM and the load. The current rise time was reduced to ~300 ns. We explored the use of a reduced-height wire array for the Dynamic Flux Extruder in order to improve the wire array compression rate and increase the efficiency of the current transfer to the load. These developments are presented. Potential benefits of these developments for future Z pinch experiments are discussed.

  9. Investigation of Magnetic Field Geometry in Exploding Wire Z-Pinches via Proton Deflectometry

    NASA Astrophysics Data System (ADS)

    Mariscal, Derek; Beg, Farhat; Wei, Mingsheng; Chittenden, Jeremy; Presura, Radu

    2012-10-01

    It is often difficult to determine the configuration of B-fields within z-pinch plasma systems. Typical laser probing diagnostics are limited by the critical density, and electrical diagnostics are prone to failure as well as perturbation of the system. The use of proton beams launched by high intensity lasers, and the subsequent tracking of their deflected trajectories, will enable access to field measurements in previously inaccessible plasma densities.The experimental testing of this method is performed at the Nevada Test Facility (NTF) using the 10J 0.3ps Leopard laser coupled to the 1.6MA ZEBRA pulsed power generator. MHD simulations of the z-pinch plasmas are performed with the 3D resistive MHD code, GORGON. Protons are then injected and tracked through the plasma using the 3D PIC Large Scale Plasma code in order to produce possible proton image plane data. The first computational demonstration of protons propagating through single wire and x-pinch plasmas, along with comparison to recent experimental data will be presented.

  10. Ion probe beam experiments and kinetic modeling in a dense plasma focus Z-pinch

    SciTech Connect

    Schmidt, A. Ellsworth, J. Falabella, S. Link, A. McLean, H. Rusnak, B. Sears, J. Tang, V.; Welch, D.

    2014-12-15

    The Z-pinch phase of a dense plasma focus (DPF) emits multiple-MeV ions in a ∼cm length. The mechanisms through which these physically simple devices generate such high energy beams in a relatively short distance are not fully understood. We are exploring the origins of these large gradients using measurements of an ion probe beam injected into a DPF during the pinch phase and the first kinetic simulations of a DPF Z-pinch. To probe the accelerating fields in our table top experiment, we inject a 4 MeV deuteron beam along the z-axis and then sample the beam energy distribution after it passes through the pinch region. Using this technique, we have directly measured for the first time the acceleration of an injected ion beam. Our particle-in-cell simulations have been benchmarked on both a kJ-scale DPF and a MJ-scale DPF. They have reproduced experimentally measured neutron yields as well as ion beams and EM oscillations which fluid simulations do not exhibit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for accelerator and neutron source applications.

  11. Predictive Fully Kinetic Modeling of kJ and MJ Dense Plasma Focus Z-Pinches

    NASA Astrophysics Data System (ADS)

    Link, A.; Ellsworth, J.; Falabella, S.; McLean, H.; Rusnak, B.; Schmidt, A.; Sears, J.; Tang, V.; Welch, D.

    2013-10-01

    Dense plasma focus (DPF) Z-pinches are compact devices capable of producing MeV ion beams, x-rays, and (for D or DT gas fill) neutrons but the details of the mechanisms which give rise to these strong accelerating gradients are not well understood. We report on progress in developing predictive, fully kinetic simulations of DPF Z-Pinches using the particle-in-cell code LSP. These simulations include full-scale electrodes; both run-in and pinch phases; and post-pinch behavior. Here we present a comparison between simulations and experiments conducted on the LLNL 4 kJ tabletop DPF. Diagnostics allow us to measure neutron yield, plasma oscillations arising from instabilities, DPF ion beam energies, and the acceleration of an externally injected ion probe beam in the pinch region, which can be compared with simulations. We will further report on the initial work to extend these simulations from kJ to MJ-class devices. LLNL-ABS-640759. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.

  12. Cylindrical liner Z-pinch experiments for fusion research and high-energy-density physics

    NASA Astrophysics Data System (ADS)

    Burdiak, G. C.; Lebedev, S. V.; Suzuki-Vidal, F.; Swadling, G. F.; Bland, S. N.; Niasse, N.; Suttle, L.; Bennet, M.; Hare, J.; Weinwurm, M.; Rodriguez, R.; Gil, J.; Espinosa, G.

    2015-06-01

    A gas-filled cylindrical liner z-pinch configuration has been used to drive convergent radiative shock waves into different gases at velocities of 20-50 km s-1. On application of the 1.4 MA, 240 ns rise-time current pulse produced by the Magpie generator at Imperial College London, a series of cylindrically convergent shock waves are sequentially launched into the gas-fill from the inner wall of the liner. This occurs without any bulk motion of the liner wall itself. The timing and trajectories of the shocks are used as a diagnostic tool for understanding the response of the liner z-pinch wall to a large pulsed current. This analysis provides useful data on the liner resistivity, and a means to test equation of state (EOS) and material strength models within MHD simulation codes. In addition to providing information on liner response, the convergent shocks are interesting to study in their own right. The shocks are strong enough for radiation transport to influence the shock wave structure. In particular, we see evidence for both radiative preheating of material ahead of the shockwaves and radiative cooling instabilities in the shocked gas. Some preliminary results from initial gas-filled liner experiments with an applied axial magnetic field are also discussed.

  13. Analytic model to estimate thermonuclear neutron yield in z-pinches using the magnetic Noh problem

    NASA Astrophysics Data System (ADS)

    Allen, Robert C.

    The objective was to build a model which could be used to estimate neutron yield in pulsed z-pinch experiments, benchmark future z-pinch simulation tools and to assist scaling for breakeven systems. To accomplish this, a recent solution to the magnetic Noh problem was utilized which incorporates a self-similar solution with cylindrical symmetry and azimuthal magnetic field (Velikovich, 2012). The self-similar solution provides the conditions needed to calculate the time dependent implosion dynamics from which batch burn is assumed and used to calculate neutron yield. The solution to the model is presented. The ion densities and time scales fix the initial mass and implosion velocity, providing estimates of the experimental results given specific initial conditions. Agreement is shown with experimental data (Coverdale, 2007). A parameter sweep was done to find the neutron yield, implosion velocity and gain for a range of densities and time scales for DD reactions and a curve fit was done to predict the scaling as a function of preshock conditions.

  14. Magnetic Field Measurements in Wire-Array Z-Pinches using Magneto-Optically Active Waveguides

    SciTech Connect

    Syed, Wasif; Blesener, Isaac; Hammer, David A.; Lipson, Michal

    2009-01-21

    Understanding the magnetic field topology in wire-array Z-pinches as a function of time is of great significance to understanding these high-energy density plasmas especially for their ultimate application to stockpile stewardship and inertial confinement fusion. We are developing techniques to measure magnetic fields as a function of space and time using Faraday rotation of a single longitudinal mode (SLM) laser through a magneto-optically active bulk waveguide (multicomponent terbium borate glass) placed adjacent to, or within, the wire array in 1 MA experiments. We have measured fields >10 T with 100 ns rise times outside of a wire-array for the entire duration of the current pulse and as much as {approx}2 T inside a wire-array for {approx}40 ns from the start of current. This is the first time that such rapidly varying and large fields have been measured using these materials. In a dense Z-pinch, these sensing devices may not survive for long but may provide the magnetic field at the position of the sensor that can be used to corroborate magnetic probes, with which we compare our results.

  15. Optical Spectroscopy Measurements of Shock Waves Driven by Intense Z-Pinch Radiation

    SciTech Connect

    Asay, J. Bernard, M.; Bailey, J.E.; Carlson, A.L.; Chandler, G.A.; Hall, C.A.; Hanson, D.; Johnston, R.; Lake, P.; Lawrence, J.

    1999-04-09

    Z-pinches created using the Z accelerator generate {approximately}220 TW, 1.7 MJ radiation pulses that heat large ({approximately}10 cm{sup 3}) hohlraums to 100-150 eV temperatures for times of order 10 nsec. We are performing experiments exploiting this intense radiation to drive shock waves for equation of state studies. The shock pressures are typically 1-10 Mbar with 10 nsec duration in 6-mm-diameter samples. In this paper we demonstrate the ability to perform optical spectroscopy measurements on shocked samples located in close proximity to the z-pinch. These experiments are particularly well suited to optical spectroscopy measurements because of the relatively large sample size and long duration. The optical emission is collected using fiber optics and recorded with a streaked spectrograph. Other diagnostics include VISAR and active shock breakout measurements of the shocked sample and a suite of diagnostics that characterize the radiation drive. Our near term goal is to use the spectral emission to obtain the temperature of the shocked material. Longer term objectives include the examination of deviations of the spectrum from blackbody, line emission from lower density regions, determination of kinetic processes in molecular systems, evaluation of phase transitions such as the onset of metalization in transparent materials, and characterization of the plasma formed when the shock exits the rear surface. An initial set of data illustrating both the potential and the challenge of these measurements is described.

  16. Ion probe beam experiments and kinetic modeling in a dense plasma focus Z-pinch

    NASA Astrophysics Data System (ADS)

    Schmidt, A.; Ellsworth, J.; Falabella, S.; Link, A.; McLean, H.; Rusnak, B.; Sears, J.; Tang, V.; Welch, D.

    2014-12-01

    The Z-pinch phase of a dense plasma focus (DPF) emits multiple-MeV ions in a ˜cm length. The mechanisms through which these physically simple devices generate such high energy beams in a relatively short distance are not fully understood. We are exploring the origins of these large gradients using measurements of an ion probe beam injected into a DPF during the pinch phase and the first kinetic simulations of a DPF Z-pinch. To probe the accelerating fields in our table top experiment, we inject a 4 MeV deuteron beam along the z-axis and then sample the beam energy distribution after it passes through the pinch region. Using this technique, we have directly measured for the first time the acceleration of an injected ion beam. Our particle-in-cell simulations have been benchmarked on both a kJ-scale DPF and a MJ-scale DPF. They have reproduced experimentally measured neutron yields as well as ion beams and EM oscillations which fluid simulations do not exhibit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for accelerator and neutron source applications.

  17. Magnetic Field Measurements in Wire-Array Z-Pinches using Magneto-Optically Active Waveguides

    NASA Astrophysics Data System (ADS)

    Syed, Wasif; Hammer, David; Lipson, Michal

    2007-11-01

    Understanding the magnetic field topology in wire-array Z-pinches as a function of time is of great significance to understanding these high-energy density plasmas. We are developing techniques to measure magnetic fields as a function of space and time using Faraday rotation of a single longitudinal mode (SLM) laser through a magneto-optically active bulk waveguide (terbium borate glass) placed adjacent to, or within, the wire array in experiments on the COBRA pulsed power generator [1]. We have measured fields >10 T with 100 ns rise times outside of a wire-array for the entire duration of the current pulse and as much as ˜2 T inside a wire-array for ˜40 ns from the start of current. This is the first time that such rapidly varying and large fields have been measured using these materials. We will also present our progress on field measurements using an optical fiber sensor and a very small ``thin film waveguide'' coupled to a fiber optic system. In a dense Z-pinch, these sensing devices may not survive for long but may provide the magnetic field at the position of the sensor for a greater fraction of the current pulse than magnetic probes, with which we compare our results. This research was sponsored by NNSA under SSAA program via DOE Coop Agreement DE-F03-02NA00057. [1] W. Syed, D. A. Hammer, & M. Lipson, 34^th ICOPS & 16^th PPPS, Albuquerque, NM, June 2007.

  18. PBFA II-Z: A 20-MA driver for z-pinch experiments

    SciTech Connect

    1995-12-01

    Sandia is modifying the PBFA II accelerator into a dual use facility. While maintaining the present ion-beam capability, we are developing a long-pulse, high-current operating mode for magnetically-driven implosions. This option, called PBFA II-Z, will require new water transmission lines, a new insulator stack, and new magnetically-insulated transmission lines (MITLs). Each of the existing 36, coaxial water pulse-forming sections will couple to a 4.5-{Omega}, bi-plate water-transmission line. The water transmission lines then feed a four-level insulator stack. The insulators are expected to operate at a maximum, spatially-averaged electric field of {approximately}l00 kV/cm. The MITL design is based on the successful biconic Saturn design. The four ``disk`` feeds will each have a vacuum impedance of {approximately}2.0 {Omega}. The disk feeds are added in parallel using a double post-hole convolute at a diameter of 15 cm. We predict that the accelerator will deliver 20 MA to a 15-mg z-pinch load in 100 ns, making PBFA II-Z the most powerful z-pinch driver in the world providing a pulsed power and load physics scaling testbed for future 40-80-MA drivers.

  19. History of HERMES III diode to z-pinch breakthrough and beyond :

    SciTech Connect

    Sanford, Thomas Williamlou.

    2013-04-01

    HERMES III and Z are two flagship accelerators of Sandias pulsed-power program developed to generate intense -ray fields for the study of nuclear radiation effects, and to explore high energy-density physics (including the production of intense x-ray fields for Inertia Confinement Fusion [ICF]), respectively. A diode at the exit of HERMES III converts its 20-MeV electron beam into -rays. In contrast, at the center of Z, a z-pinch is used to convert its 20-MA current into an intense burst of x-rays. Here the history of how the HERMES III diode emerged from theoretical considerations to actual hardware is discussed. Next, the reverse process of how the experimental discovery of wire-array stabilization in a z-pinch, led to a better theory of wirearray implosions and its application to one of the ICF concepts on Z--the DH (Dynamic Hohlraum) is reviewed. Lastly, the report concludes with how the unexpected axial radiation asymmetry measured in the DH is understood. The first discussion illustrates the evolution of physics from theory-to-observationto- refinement. The second two illustrate the reverse process of observationto- theory-to refinement. The histories are discussed through the vehicle of my research at Sandia, illustrating the unique environment Sandia provides for personal growth and development into a scientific leader.

  20. Magnetic Field Measurements in Wire-Array Z-Pinches using Magneto-Optically Active Waveguides

    NASA Astrophysics Data System (ADS)

    Syed, Wasif; Blesener, Isaac; Hammer, David A.; Lipson, Michal

    2009-01-01

    Understanding the magnetic field topology in wire-array Z-pinches as a function of time is of great significance to understanding these high-energy density plasmas especially for their ultimate application to stockpile stewardship and inertial confinement fusion. We are developing techniques to measure magnetic fields as a function of space and time using Faraday rotation of a single longitudinal mode (SLM) laser through a magneto-optically active bulk waveguide (multicomponent terbium borate glass) placed adjacent to, or within, the wire array in 1 MA experiments. We have measured fields >10 T with 100 ns rise times outside of a wire-array for the entire duration of the current pulse and as much as ˜2 T inside a wire-array for ˜40 ns from the start of current. This is the first time that such rapidly varying and large fields have been measured using these materials. In a dense Z-pinch, these sensing devices may not survive for long but may provide the magnetic field at the position of the sensor that can be used to corroborate magnetic probes, with which we compare our results.

  1. Primary experimental results of wire-array Z-pinches on PTS

    SciTech Connect

    Huang, X. B. Zhou, S. T. Ren, X. D. Dan, J. K. Wang, K. L. Zhang, S. Q. Li, J. Xu, Q. Cai, H. C. Duan, S. C. Ouyang, K. Chen, G. H. Ji, C. Wang, M. Feng, S. P. Yang, L. B. Xie, W. P. Deng, J. J.

    2014-12-15

    The Primary Test Stand (PTS) developed at the China Academy of Engineering Physics is a multiterawatt pulsed power driver, which can deliver a ∼10 MA, 70 ns rise-time (10%-90%) current to a short circuit load and has important applications in Z-pinch driven inertial confinement fusion and high energy density physics. In this paper, primary results of tungsten wire-array Z-pinch experiments on PTS are presented. The load geometries investigated include 15-mm-tall cylindrical single and nested arrays with diameter ranging from 14.4-26.4 mm, and consisting of 132∼276 tungsten wires with 5∼10 μm in diameter. Multiple diagnostics were fielded to determine the characteristics of x-ray radiations and to obtain self-emitting images of imploding plasmas. X-ray power up to 80 TW with ∼3 ns FWMH is achieved by using nested wire arrays. The total x-ray energy exceeds 500 kJ and the peak radiation temperature is about 150 eV. Typical velocity of imploding plasmas goes around 3∼5×10{sup 7} cm/s and the radial convergence ratio is between 10 and 20.

  2. Ion Beam Driven Shock Device Using Accelerated High Density Plasmoid by Phased Z-Pinch

    NASA Astrophysics Data System (ADS)

    Horioka, Kazuhiko; Aizawa, Tatsuhiko; Tsuchida, Minoru

    1997-07-01

    Different from three methods to generate high shock pressure by acceleration of high density plasma or particles (intense ion beams, plasma gun and rail gun) having their intrinsic deficiencies, new frontier is proposed to propel the shock physics and chemistry by using the high density plasma. In the present paper, new scheduled Z-pinch method is developed as a new device to generate high shock pressure. In the present method, plasma density can be compressed to the order of 10^18 to 10^19 cm-3, and high density plasma can be accelerated by zippering together with axial shock pressure, resulting in high-velocity launching of flyer. In the present paper, systematic experimental works are performed to demonstrate that high energy plasma flow can be electro-magnetically driven by the scheduled capillary Z-pinch, and to characterize the ion velocity and its current density. The estimated value of ion speed from the plasma-measurement reaches to 7 x 10^7 cm/s corresponding to 70 to 100 KeV for Ar. Copper flyer can be shot with the velocity range from 1km/s to 3km/s in the standard condition.

  3. Design of the PST: A Diagnostic for 1-D Imaging of Fast Z-Pinch Power Emissions

    SciTech Connect

    ROCHAU,GREGORY A.; DERZON,MARK S.; CHANDLER,GORDON A.; LAZIER,STEVEN EARL

    2000-08-03

    Fast Z-pinch technology developed on the Z machine at Sandia National Laboratories can produce up to 230 TW of thermal x-ray power for applications in inertial confinement fusion (ICF) and weapons physics experiments. During implosion, these Z-pinches develop Rayleigh-Taylor (R-T) instabilities which are very difficult to diagnose and which functionally diminish the overall pinch quality. The Power-Space-Time (PST) instrument is a newly configured diagnostic for measuring the pinch power as a function of both space and time in a Z-pinch. Placing the diagnostic at 90 degrees from the Z-pinch axis, the PST provides a new capability in collecting experimental data on R-T characteristics for making meaningful comparisons to magneto-hydrodynamic computer models. This paper is a summary of the PST diagnostic design. By slit-imaging the Z-pinch x-ray emissions onto a linear scintillator/fiber-optic array coupled to a streak camera system, the PST can achieve {approximately}100 {micro}m spatial resolution and {approximately}1.3 ns time resolution. Calculations indicate that a 20 {micro}m thick scintillating detection element filtered by 1,000 {angstrom} of Al is theoretically linear in response to Plankian x-ray distributions corresponding to plasma temperatures from 40 eV to 150 eV, By calibrating this detection element to x-ray energies up to 5,000 eV, the PST can provide pinch power as a function of height and time in a Z-pinch for temperatures ranging from {approximately}40 eV to {approximately}400 eV. With these system pm-meters, the PST can provide data for an experimental determination of the R-T mode number, amplitude, and growth rate during the late-time pinch implosion.

  4. Z-Pinch Magneto-Inertial Fusion Propulsion Engine Design Concept

    NASA Technical Reports Server (NTRS)

    Miernik, Janie H.; Statham, Geoffrey; Adams, Robert B.; Polsgrove, Tara; Fincher, Sharon; Fabisinski, Leo; Maples, C. Dauphne; Percy, Thomas K.; Cortez, Ross J.; Cassibry, Jason

    2011-01-01

    Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Due to the great distances between the planets of our solar system and the harmful radiation environment of interplanetary space, high specific impulse (Isp) propulsion in vehicles with high payload mass fractions must be developed to provide practical and safe vehicles for human spaceflight missions. Magneto-Inertial Fusion (MIF) is an approach which has been shown to potentially lead to a low cost, small fusion reactor/engine assembly (1). The Z-Pinch dense plasma focus method is an MIF concept in which a column of gas is compressed to thermonuclear conditions by an estimated axial current of approximately 100 MA. Recent advancements in experiments and the theoretical understanding of this concept suggest favorable scaling of fusion power output yield as I(sup 4) (2). The magnetic field resulting from the large current compresses the plasma to fusion conditions, and this is repeated over short timescales (10(exp -6) sec). This plasma formation is widely used in the field of Nuclear Weapons Effects (NWE) testing in the defense industry, as well as in fusion energy research. There is a wealth of literature characterizing Z-Pinch physics and existing models (3-5). In order to be useful in engineering analysis, a simplified Z-Pinch fusion thermodynamic model was developed to determine the quantity of plasma, plasma temperature, rate of expansion, energy production, etc. to calculate the parameters that characterize a propulsion system. The amount of nuclear fuel per pulse, mixture ratio of the D-T and nozzle liner propellant, and assumptions about the efficiency of the engine, enabled the sizing of the propulsion system and resulted in an estimate of the thrust and Isp of a Z-Pinch fusion propulsion system for the concept vehicle. MIF requires a magnetic nozzle to contain and direct the nuclear pulses, as well as a robust structure and radiation shielding. The structure

  5. Implosion dynamics and radiation characteristics of wire-array Z pinches on the Cornell Beam Research Accelerator

    SciTech Connect

    McBride, R. D.; Shelkovenko, T. A.; Pikuz, S. A.; Hammer, D. A.; Greenly, J. B.; Kusse, B. R.; Douglass, J. D.; Knapp, P. F.; Bell, K. S.; Blesener, I. C.; Chalenski, D. A.

    2009-01-15

    Experimental results are presented that characterize the implosion dynamics and radiation output of wire-array Z pinches on the 1-MA, 100-ns rise-time Cornell Beam Research Accelerator (COBRA) [J. B. Greenly et al., Rev. Sci. Instrum. 79, 073501 (2008)]. The load geometries investigated include 20-mm-tall cylindrical arrays ranging from 4 to 16 mm in diameter, and consisting of 8, 16, or 32 wires of either tungsten, aluminum, or Invar (64% iron, 36% nickel). Diagnostics fielded include an optical streak camera, a time-gated extreme-ultraviolet framing camera, a laser shadowgraph system, time-integrated pinhole cameras, an x-ray wide-band focusing spectrograph with spatial resolution, an x-ray streak camera, a load voltage monitor, a Faraday cup, a bolometer, silicon diodes, and diamond photoconducting detectors. The data produced by the entire suite of diagnostics are analyzed and presented to provide a detailed picture of the overall implosion process and resulting radiation output on COBRA. The highest x-ray peak powers (300-500 GW) and total energy yields (6-10 kJ) were obtained using 4-mm-diameter arrays that stagnated before peak current. Additional findings include a decrease in soft x-ray radiation prior to stagnation as the initial wire spacing was changed from 1.6 mm to 785 {mu}m, and a timing correlation between the onset of energetic electrons, hard x-ray generation, and the arrival of trailing current on axis - a correlation that is likely due to the formation of micropinches. The details of these and other findings are presented and discussed.

  6. Implosion dynamics and radiation characteristics of wire-array Z pinches on the Cornell Beam Research Accelerator

    NASA Astrophysics Data System (ADS)

    McBride, R. D.; Shelkovenko, T. A.; Pikuz, S. A.; Hammer, D. A.; Greenly, J. B.; Kusse, B. R.; Douglass, J. D.; Knapp, P. F.; Bell, K. S.; Blesener, I. C.; Chalenski, D. A.

    2009-01-01

    Experimental results are presented that characterize the implosion dynamics and radiation output of wire-array Z pinches on the 1-MA, 100-ns rise-time Cornell Beam Research Accelerator (COBRA) [J. B. Greenly et al., Rev. Sci. Instrum. 79, 073501 (2008)]. The load geometries investigated include 20-mm-tall cylindrical arrays ranging from 4to16mm in diameter, and consisting of 8, 16, or 32 wires of either tungsten, aluminum, or Invar (64% iron, 36% nickel). Diagnostics fielded include an optical streak camera, a time-gated extreme-ultraviolet framing camera, a laser shadowgraph system, time-integrated pinhole cameras, an x-ray wide-band focusing spectrograph with spatial resolution, an x-ray streak camera, a load voltage monitor, a Faraday cup, a bolometer, silicon diodes, and diamond photoconducting detectors. The data produced by the entire suite of diagnostics are analyzed and presented to provide a detailed picture of the overall implosion process and resulting radiation output on COBRA. The highest x-ray peak powers (300-500GW) and total energy yields (6-10kJ) were obtained using 4-mm-diameter arrays that stagnated before peak current. Additional findings include a decrease in soft x-ray radiation prior to stagnation as the initial wire spacing was changed from 1.6mmto785μm, and a timing correlation between the onset of energetic electrons, hard x-ray generation, and the arrival of trailing current on axis—a correlation that is likely due to the formation of micropinches. The details of these and other findings are presented and discussed.

  7. Pinch me - I'm fusing! Fusion Power - what is it? What is a z pinch? And why are z-pinches a promising fusion power technology?

    SciTech Connect

    DERZON,MARK S.

    2000-03-01

    The process of combining nuclei (the protons and neutrons inside an atomic nucleus) together with a release of kinetic energy is called fusion. This process powers the Sun, it contributes to the world stockpile of weapons of mass destruction and may one day generate safe, clean electrical power. Understanding the intricacies of fusion power, promised for 50 years, is sometimes difficult because there are a number of ways of doing it. There is hot fusion, cold fusion and con-fusion. Hot fusion is what powers suns through the conversion of mass energy to kinetic energy. Cold fusion generates con-fusion and nobody really knows what it is. Even so, no one is generating electrical power for you and me with either method. In this article the author points out some basic features of the mainstream approaches taken to hot fusion power, as well as describe why z pinches are worth pursuing as a driver for a power reactor and how it may one day generate electrical power for mankind.

  8. Long-length, long-lived flow-shear stabilized Z-pinches: Background and Experimental plans for scaling studies

    NASA Astrophysics Data System (ADS)

    Nelson, B. A.; Shumlak, U.; Golingo, R. P.; Claveau, E. L.; McLean, H. S.; Schmidt, A. E.

    2015-11-01

    The ZaP experiment produces long-lived sheared-flow-stabilized Z-pinch plasmas up to 126 cm in length for several flow-through times, and up to thousands of Alfvén times. Experimental measurements of the magnetic structure along the full length of the plasma column show an axially uniform Z-pinch plasma during the observed quiescent period. Interferometry, fast-framing images, and Rogowskii coils corroborate the existence of a pinched plasma during this quiescent period of time. Detailed two-dimensional non-linear magnetohydrodynamic (MHD) calculations have been performed showing the formation and assembly of long-length, long-lived Z-pinches. Experimentally-observed plasma lifetimes and velocity-shear profiles are shown to be consistent with calculations of viscous-damping timescales based on the measured plasma parameters. A newly-funded ARPA-E ALPHA project, the Fusion Z-pinch Experiment ``FuZE'' is being constructed at the University of Washington, in collaboration with the Lawrence Livermore National Laboratory. FuZE will study scaling and stability of the successful ZaP experiment to higher pinch currents. The FuZE experimental design, goals, and plans, based on ZaP experimental results, will be presented.

  9. Four-color laser diagnostics for Z-pinch and laser-produced plasma.

    PubMed

    Ivanov, V V; Anderson, A A; Begishev, I A

    2016-01-20

    Four-color laser diagnostics were developed for Z-pinch and laser plasma at the 1 MA pulsed power generator. Four harmonics of the Nd:YAG laser at wavelengths of 1064, 532, 266, and 213 nm were produced during the cascade conversion in three nonlinear crystals and propagated together in one beampath. Deep UV probing allows better penetration of the dense plasma. Laser probing at four wavelengths allows observation of plasma in a wide range of densities in one shot of the diagnostic laser. Examples of four-color laser shadowgraphy and interferometry of the wire-array load and laser plasma interaction are presented and discussed. PMID:26835923

  10. Gas Puff Preionization For Improved X-ray Yield from Z-Pinch Plasma Radiating Sources

    NASA Astrophysics Data System (ADS)

    Moosman, B.; Commisso, R. J.; Fisher, A.; Stephanakis, S. J.; Weber, B. V.

    1998-11-01

    Azimuthally symmetric preionization via peripheral UV illumination is suggested as a method for improving x-ray yield in gas puff z-pinches. UV gas preionization was characterized via high-sensitivity interferometry and deployed on the DECADE MODULE 2 (DM2). The UV preionization is provided by a high-current, 40-kA, surface discharge on the inner diameter of a ring located near the gas puff and produces 1-10 % gas ionization. Early experiments on DM2 indicated that UV preionization may eliminate sporadic low x-ray yield shots from a series of similar initial condition shots. E-beam preionization using a single carbon brush, pointed perpendicular to the gas flow, was also characterized. The use of multiple high impedance e-beam guns for gas preionization presents a possible alternative to high current UV preionization.

  11. Development of absorption spectroscopy for wire-array Z-pinches

    NASA Astrophysics Data System (ADS)

    Anderson, A.; Ivanov, V. V.; Hakel, P.; Mancini, R. C.; Wiewior, P.; Durmaz, T.; Astanovitskiy, A. L.; Chalyy, O.; Altemara, S. D.; Papp, D.; McKee, E.; Chittenden, J. P.; Niasse, N.; Shevelko, A. P.

    2010-11-01

    The 50 TW Leopard laser was coupled with the 1 MA Zebra generator for the x-ray backlighting of wire arrays. The Leopard laser is based on the chirped pulse amplification and can operate in subpicosecond or subnanosecond regimes. Several materials were tested in both regimes and samarium was selected for subnanosecond backlighting in the range of 7-9 å. One ray of Al wire-arrays was investigated at the ablation and implosion stages. Two focusing conical spectrometers with mica crystals recorded reference and main spectra on x-ray film. Collimators protected spectrometers against the x-ray burst from the main Z-pinch. Comparison of spectra of backlighting radiation with reference spectra indicates absorption lines in the range of 8.2-8.4 å. The electron temperature of wire-array plasma was estimated from simulations with atomic kinetics models.

  12. Dense Plasma Focus Z-pinches for High Gradient Particle Acceleration

    SciTech Connect

    Tang, V; Adams, M L; Rusnak, B

    2009-07-24

    The final Z-pinch stage of a Dense Plasma Focus (DPF) could be used as a simple, compact, and potentially rugged plasma-based high-gradient accelerator with fields at the 100 MV/m level. In this paper we review previously published experimental beam data that indicate the feasibility of such an DPF-based accelerator, qualitatively discuss the physical acceleration processes in terms of the induced voltages, and as a starting point examine the DPF acceleration potential by numerically applying a self-consistent DPF system model that includes the induced voltage from both macroscopic and instability driven plasma dynamics. Applications to the remote detection of high explosives and a multi-staged acceleration concept are briefly discussed.

  13. Extreme Ultraviolet Light Emission from Z-Pinch Discharge Plasma Source

    NASA Astrophysics Data System (ADS)

    Watanabe, Masato; Song, Inho; Sakamoto, Toshiro; Kobayashi, Yasunori; Okino, Akitoshi; Mohanty, Smruti R.; Horioka, Kazuhiko; Hotta, Eiki

    2006-01-01

    A capillary Z-pinch discharge light source for EUV lithography has been developed. Our device is equipped with a water-cooled ceramic capillary and electrodes, and a solid state pulsed power generator. A stacked static induction thyristors are used as switching elements, which enable high repetition rate operation of pulsed power supply. A magnetic switch is connected in series, which not only assists the semiconductor switch but also provides a preionization current. In the present study, EUV radiation emitted from pinching plasma in a xenon-filled capillary was quantitatively measured using an in-band calorimeter. Time-integrated in-band source image was also observed using a pinhole camera system. Furthermore, new electrode system using plasma jet has been developed.

  14. Magneto-Hydrodynamic Modeling in the Design and Interpretation of Wire Array Z-pinches

    SciTech Connect

    Chittenden, J. P.; Niasse, N. P.; Jennings, C. A.

    2009-01-21

    Magneto-hydrodynamic simulations provide a powerful tool for improving our understanding of the complex physical processes underlying the behavior of wire array Z-pinches. We show how, by using large scale parallel 3D simulations of the array as a whole, it is possible to encompass all of the important features of the wire ablation, implosion and stagnation phases and to observe how these phenomena control the X-ray pulse that is achieved. Comparison of code results with experimental data from the 'Z' and MAGPIE pulsed power generators is shown to provide a detailed benchmark test for the models. The simulation results are also used to highlight key areas for future research.

  15. The effects of insulating coatings and current prepulse on tungsten planar wire array Z-pinches

    SciTech Connect

    Li, M. Li, Y.; Sheng, L.; Wang, L. P.; Zhao, C.; Yuan, Y.; Zhang, X. J.; Zhang, M.; Peng, B. D.; Zhang, J. H.; Zhang, S. G.; Qiu, M. T.; Li, X. W.

    2015-12-15

    This paper presents experimental results on the effects of insulating coatings and current prepulse on tungsten planar wire array Z-pinches on ∼100 ns main current facility. Optical framing images indicated that without a current prepulse the wire ablation process was asymmetrical and the implosion was zippered. The x-ray peak power was ∼320 GW. By using insulating coatings on the wire surface the asymmetry remained, and the processes of ablation and implosion were delayed by ∼30 ns. The x-ray burst was narrow and decreased to ∼200 GW. When current prepulses were used on both standard and insulated wire arrays, implosion symmetry was improved and the x-ray burst was improved (to ∼520 GW peak power). In addition, there was a strong emitting precursor column for insulated loads with the current prepulse.

  16. Equilibrium and Steady State of Dense Z-Pinches Superposing a Small Amount of Axial Flux

    NASA Astrophysics Data System (ADS)

    Hashimoto, Mitsuhiro; Miyamoto, Tetsu

    2016-07-01

    The pressure equilibrium and steady state of z-pinches trapping a small amount of axial magnetic flux are studied. The Bennett relation and the Pease-Braginskii-current are modified, taking into account the superposed axial field. The line energy density decreases in the modified Bennett relation, but the decrease is only of the order ɛ2, where ɛ = (the axial field strength at the axis)/(the azimuthal field strength at the plasma periphery) ≪ 1. On the other hand, the current in the steady state can increase without being limited by the Pease-Braginskii-current. Hence, the radiation collapse is prevented. The decrease of line energy density in the modified Bennett relation is almost canceled in the steady state.

  17. MAIZE: a 1 MA LTD-Driven Z-Pinch at The University of Michigan

    SciTech Connect

    Gilgenbach, R. M.; Gomez, M. R.; Zier, J. C.; Tang, W. W.; French, D. M.; Lau, Y. Y.; Mazarakis, M. G.; Cuneo, M. E.; Johnston, M. D.; Oliver, B. V.; Mehlhorn, T. A.; Kim, A. A.; Sinebryukhov, V. A.

    2009-01-21

    Researchers at The University of Michigan have constructed and tested a 1-MA Linear Transformer Driver (LTD), the first of its type to reach the USA. The Michigan Accelerator for Inductive Z-pinch Experiments, (MAIZE), is based on the LTD developed at the Institute of High Current Electronics in collaboration with Sandia National Labs and UM. This LTD utilizes 80 capacitors and 40 spark gap switches, arranged in 40 'bricks,' to deliver a 1 MA, 100 kV pulse with 100 ns risetime into a matched resistive load. Preliminary resistive-load test results are presented for the LTD facility.Planned experimental research programs at UM include: a) Studies of Magneto-Raleigh-Taylor instability of planar foils, and b) Vacuum convolute studies including cathode and anode plasma.

  18. 3D MHD Simulations of Radial Wire Array Z-pinches

    NASA Astrophysics Data System (ADS)

    Niasse, N.; Chittenden, J. P.; Bland, S. N.; Suzuki-Vidal, F. A.; Hall, G. N.; Lebedev, S. V.; Calamy, H.; Zucchini, F.; Lassalle, F.; Bedoch, J. P.

    2009-01-01

    Recent experiments carried out on the MAGPIE (1 MA, 250 ns), OEDIPE (730 kA, 1.5 μs) and SPHINX (4 MA, 700 ns)[1] facilities have shown the relatively high level of scalability of the Radial Wire Array Z-pinches. These configurations where the wires stretch radially outwards from a central cathode offer numerous advantages over standard cylindrical arrays. In particular, imploding in a very stable and compact way, they seem suitable for coupling to small scale hohlraums. Making use of the 3D resistive magneto-hydrodynamic code GORGON[2] developed at Imperial College, the dynamic of the radial wire arrays is investigated. Influence of the cathode hotspots and wires angle on the x-ray emissions is also discussed. Comparison with experiments is offered to validate the numerical studies.

  19. Behavior of a plasma in a high-density gas-embedded Z-pinch configuration

    SciTech Connect

    Shlachter, J.S.

    1982-05-01

    The theoretical analysis of a high density Z-pinch (HDZP) begins with an examination of the steady state energy balance between ohmic heating and bremsstrahlung radiation losses for a plasma column in pressure equilibrium. The model is then expanded to include the time-varying internal energy and results in a quasi-equilibrium prescription for the load current through a constant radius plasma channel. This set of current waveforms is useful in the design of experimental systems. The behavior of a plasma for physically realizable conditions is first examined by allowing adiabatic changes in the column radius. A more complete model is then developed by incorporating inertial effects into the momentum equation, and the resultant global MHD computational model is compared with more sophisticated, and costly, one- and two-dimensional computer simulations. These comparisons demonstrate the advantages of the global MHD description over previously developed zero-dimensional models.

  20. Current initiation in low-density foam z-pinch plasmas

    SciTech Connect

    Derzon, M.; Nash, T.; Allshouse, G.

    1996-07-01

    Low density agar and aerogel foams were tested as z-pinch loads on the SATURN accelerator. In these first experiments, we studied the initial plasma conditions by measuring the visible emission at early times with a framing camera and 1-D imaging. At later time, near the stagnation when the plasma is hotter, x-ray imaging and spectral diagnostics were used to characterize the plasma. Filamentation and arcing at the current contacts was observed. None of the implosions were uniform along the z-axis. The prime causes of these problems are believed to be the electrode contacts and the current return configuration and these are solvable. Periodic phenomena consistent with the formation of instabilities were observed on one shot, not on others, implying that there may be a way of controlling instabilities in the pinch. Many of the issues involving current initiation may be solvable. Solutions are discussed.

  1. 250 kA compact linear transformer driver for wire array z-pinch loads

    NASA Astrophysics Data System (ADS)

    Bott, S. C.; Haas, D. M.; Madden, R. E.; Ueda, U.; Eshaq, Y.; Collins, G., IV; Gunasekera, K.; Mariscal, D.; Peebles, J.; Beg, F. N.; Mazarakis, M.; Struve, K.; Sharpe, R.

    2011-05-01

    We present the application of a short rise (˜150ns) 250 kA linear transformer driver (LTD) to wire array z-pinch loads for the first time. The generator is a modification of a previous driver in which a new conical power feed provides a low inductance coupling to wire loads. Performance of the new design using both short circuit and plasma loads is presented and discussed. The final design delivers ˜200kA to a wire array load which is in good agreement with SCREAMER calculations using a simplified representative circuit. Example results demonstrate successful experiments using cylindrical, conical, and inverse wire arrays as well as previously published work on x-pinch loads.

  2. Non-thermal x-ray emission from wire array z-pinches

    SciTech Connect

    Ampleford, David; Hansen, Stephanie B.; Jennings, Christopher Ashley; Webb, Timothy Jay; Harper-Slaboszewicz, V.; Loisel, Guillaume Pascal; Flanagan, Timothy McGuire; Bell, Kate Suzanne; Jones, Brent M.; McPherson, Leroy A.; Rochau, Gregory A.; Chittenden, Jeremy P.; Sherlock, Mark; Appelbe, Brian; Giuliani, John; Ouart, Nicholas; Seely, John

    2015-12-01

    We report on experiments demonstrating the transition from thermally-dominated K-shell line emission to non-thermal, hot-electron-driven inner-shell emission for z pinch plasmas on the Z machine. While x-ray yields from thermal K-shell emission decrease rapidly with increasing atomic number Z, we find that non-thermal emission persists with favorable Z scaling, dominating over thermal emission for Z=42 and higher (hn ≥ 17keV). Initial experiments with Mo (Z=42) and Ag (Z=47) have produced kJ-level emission in the 17-keV and 22-keV Kα lines respectively. We will discuss the electron beam properties that could excite these non - thermal lines. We also report on experiments that have attempted to control non - thermal K - shell line emission by modifying the wire array or load hardware setup.

  3. Circuit model for the inverse Z-pinch wire array switch.

    SciTech Connect

    Waisman, Eduardo Mario; Cuneo, Michael Edward; Harvey-Thompson, A.; Lebedev, Sergey V.

    2010-06-01

    A 0D circuit code is introduced to study the wire array switch concept introduced in. It has been implemented and researched at Imperial College. An exploding wire array, the switch, is in parallel with the load, an imploding wire array. Most of the current flows in the exploding array until it expands and becomes highly resistive. The 0D code contains simple models of Joule energy deposition and plasma expansion for W and Al wires. The purpose of the device is to produce fast Z-pinch implosion, below 100ns on MAGPIE and the Sandia Z machine. Self and mutual inductances are taken into consideration as well as the rocket model for wire ablation. The switch characteristics of the exploding array are prescribed and tuned up to agree with MAGPIE shots. The dependence of the device on the configuration of the arrays is studied and scaling to ZR conditions is explored.

  4. Ion Viscous Heating in a Magnetohydrodynamically Unstable Z Pinch at Over 2×109 Kelvin

    NASA Astrophysics Data System (ADS)

    Haines, M. G.; Lepell, P. D.; Coverdale, C. A.; Jones, B.; Deeney, C.; Apruzese, J. P.

    2006-02-01

    Pulsed power driven metallic wire-array Z pinches are the most powerful and efficient laboratory x-ray sources. Furthermore, under certain conditions the soft x-ray energy radiated in a 5 ns pulse at stagnation can exceed the estimated kinetic energy of the radial implosion phase by a factor of 3 to 4. A theoretical model is developed here to explain this, allowing the rapid conversion of magnetic energy to a very high ion temperature plasma through the generation of fine scale, fast-growing m=0 interchange MHD instabilities at stagnation. These saturate nonlinearly and provide associated ion viscous heating. Next the ion energy is transferred by equipartition to the electrons and thus to soft x-ray radiation. Recent time-resolved iron spectra at Sandia confirm an ion temperature Ti of over 200 keV (2×109 degrees), as predicted by theory. These are believed to be record temperatures for a magnetically confined plasma.

  5. 2D radiation-magnetohydrodynamic simulations of SATURN imploding Z-pinches

    SciTech Connect

    Hammer, J.H.; Eddleman, J.L.; Springer, P.T.

    1995-11-06

    Z-pinch implosions driven by the SATURN device at Sandia National Laboratory are modeled with a 2D radiation magnetohydrodynamic (MHD) code, showing strong growth of magneto-Rayleigh Taylor (MRT) instability. Modeling of the linear and nonlinear development of MRT modes predicts growth of bubble-spike structures that increase the time span of stagnation and the resulting x-ray pulse width. Radiation is important in the pinch dynamics keeping the sheath relatively cool during the run-in and releasing most of the stagnation energy. The calculations give x-ray pulse widths and magnitudes in reasonable agreement with experiments, but predict a radiating region that is too dense and radially localized at stagnation. We also consider peaked initial density profiles with constant imploding sheath velocity that should reduce MRT instability and improve performance. 2D krypton simulations show an output x-ray power > 80 TW for the peaked profile.

  6. Rep-rated Z-Pinch Power Plant Concept - Direct Energy Conversion and Shrapnel Generation*

    NASA Astrophysics Data System (ADS)

    de Groot, John S.; Gronbech-Jensen, Niels; Miller, Greg; Olsen, Craig L.; Rochau, Gary E.; Derzon, Mark S.; Slutz, Steven A.; Spielman, Rick B.; Peterson, Per F.; Rochau, Gregory A.; Pederson, Robert R.

    2000-10-01

    We are developing direct energy conversion schemes and shrapnel generation models to be used to optimize a high yield z-pinch IFE power plant concept. The concept uses high yield ( 10 GJ) at low rep-rate ( 0.1 Hz), with a Recyclable Transmission Line (RTL) to provide the necessary standoff between the fusion target and the power plant chamber. The RTL would be cast out of a conventional power plant coolant material (such as Li or Flibe) that can be used to absorb the fusion energy, breed tritium, and mitigate the shock to the first wall. Current results of initial work on this concept will be discussed. *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the United States Department of Energy Under Contract DE-AC04-94AL85000.

  7. Magneto-Hydrodynamic Modeling in the Design and Interpretation of Wire Array Z-pinches

    NASA Astrophysics Data System (ADS)

    Chittenden, J. P.; Niasse, N. P.; Jennings, C. A.

    2009-01-01

    Magneto-hydrodynamic simulations provide a powerful tool for improving our understanding of the complex physical processes underlying the behavior of wire array Z-pinches. We show how, by using large scale parallel 3D simulations of the array as a whole, it is possible to encompass all of the important features of the wire ablation, implosion and stagnation phases and to observe how these phenomena control the X-ray pulse that is achieved. Comparison of code results with experimental data from the 'Z' and MAGPIE pulsed power generators is shown to provide a detailed benchmark test for the models. The simulation results are also used to highlight key areas for future research.

  8. 3D MHD Simulations of Radial Wire Array Z-pinches

    SciTech Connect

    Niasse, N.; Chittenden, J. P.; Bland, S. N.; Suzuki-Vidal, F. A.; Hall, G. N.; Lebedev, S. V.; Calamy, H.; Zucchini, F.; Lassalle, F.; Bedoch, J. P.

    2009-01-21

    Recent experiments carried out on the MAGPIE (1 MA, 250 ns), OEDIPE (730 kA, 1.5 {mu}s) and SPHINX (4 MA, 700 ns)[1] facilities have shown the relatively high level of scalability of the Radial Wire Array Z-pinches. These configurations where the wires stretch radially outwards from a central cathode offer numerous advantages over standard cylindrical arrays. In particular, imploding in a very stable and compact way, they seem suitable for coupling to small scale hohlraums. Making use of the 3D resistive magneto-hydrodynamic code GORGON[2] developed at Imperial College, the dynamic of the radial wire arrays is investigated. Influence of the cathode hotspots and wires angle on the x-ray emissions is also discussed. Comparison with experiments is offered to validate the numerical studies.

  9. Use of vacuum arc plasma guns for a metal puff Z-pinch system

    SciTech Connect

    Rousskikh, A. G.; Zhigalin, A. S.; Oreshkin, V. I.; Chaikovsky, S. A.; Labetskaya, N. A.; Baksht, R. B.

    2011-09-15

    The performance of a metal puff Z-pinch system has been studied experimentally. In this type of system, the initial cylindrical shell 4 cm in diameter was produced by ten plasma guns. Each gun initiates a vacuum arc operating between magnesium electrodes. The net current of the guns was 80 kA. The arc-produced plasma shell was compressed by using a 450-kA, 450-ns driver, and as a result, a plasma column 0.3 cm in diameter was formed. The electron temperature of the plasma reached 400 eV at an average ion concentration of 1.85 {center_dot} 10{sup 18} cm{sup -3}. The power of the Mg K-line radiation emitted by the plasma for 15-30 ns was 300 MW/cm.

  10. Particle drift model for Z-pinch-driven magneto-Rayleigh-Taylor instability

    NASA Astrophysics Data System (ADS)

    Dan, Jia Kun; Xu, Qiang; Wang, Kun Lun; Ren, Xiao Dong; Huang, Xian Bin

    2016-09-01

    A theoretical model of Z-pinch driven magneto-Rayleigh-Taylor instability is proposed based on the particle drift point of view, which can explain the helical instability structure observed in premagnetized imploding liner experiments. It is demonstrated that all possible drift motions, including polarization drift, gradient drift, and curvature drift, which can lead to charge separations, each will attribute to an effective gravity acceleration. Theoretical predictions given by this model are dramatically different from those given by previous theories which have been readily recovered in the theory presented here as a limiting case. The theory shows qualitative agreement with available experimental data of the pitch angle and provides certain predictions to be verified.

  11. Design of Z-Pinch and Dense Plasma Focus Powered Vehicles

    NASA Technical Reports Server (NTRS)

    Polsgrove, Tara; Fincher, Sharon; Adams, Robert B.; Cassibry, Jason; Cortez, Ross; Turner, Matthew; Maples, C. Daphne; Miermik, Janie N.; Statham, Geoffrey N.; Fabisinski, Leo; Santarius, John; Percy, Tom

    2011-01-01

    Z-pinch and Dense Plasma Focus (DPF) are two promising techniques for bringing fusion power to the field of in-space propulsion. A design team comprising of engineers and scientists from UAHuntsville, NASA's George C. Marshall Space Flight Center and the University of Wisconsin developed concept vehicles for a crewed round trip mission to Mars and an interstellar precursor mission. Outlined in this paper are vehicle concepts, complete with conceptual analysis of the mission profile, operations, structural and thermal analysis and power/avionics design. Additionally engineering design of the thruster itself is included. The design efforts adds greatly to the fidelity of estimates for power density (alpha) and overall performance for these thruster concepts

  12. The role of Z-pinch fusion transmutation of waste in the nuclear fuel cycle.

    SciTech Connect

    Smith, James Dean; Drennen, Thomas E.; Rochau, Gary Eugene; Martin, William Joseph; Kamery, William; Phruksarojanakun, Phiphat; Grady, Ryan; Cipiti, Benjamin B.; Wilson, Paul Philip Hood; Mehlhorn, Thomas Alan; Guild-Bingham, Avery; Tsvetkov, Pavel Valeryevich

    2007-10-01

    The resurgence of interest in reprocessing in the United States with the Global Nuclear Energy Partnership has led to a renewed look at technologies for transmuting nuclear waste. Sandia National Laboratories has been investigating the use of a Z-Pinch fusion driver to burn actinide waste in a sub-critical reactor. The baseline design has been modified to solve some of the engineering issues that were identified in the first year of work, including neutron damage and fuel heating. An on-line control feature was added to the reactor to maintain a constant neutron multiplication with time. The transmutation modeling effort has been optimized to produce more accurate results. In addition, more attention was focused on the integration of this burner option within the fuel cycle including an investigation of overall costs. This report presents the updated reactor design, which is able to burn 1320 kg of actinides per year while producing 3,000 MWth.

  13. Effective versus ion thermal temperatures in the Weizmann Ne Z-pinch: Modeling and stagnation physics

    SciTech Connect

    Giuliani, J. L.; Thornhill, J. W.; Dasgupta, A.; Velikovich, A. L.; Chong, Y. K.; Mehlhorn, T. A.; Kroupp, E.; Osin, D.; Maron, Y.; Starobinets, A.; Fisher, V.; Zarnitsky, Yu.; Bernshtam, V.; Apruzese, J. P.; Fisher, A.; Deeney, C.

    2014-03-15

    The difference between the ion thermal and effective temperatures is investigated through simulations of the Ne gas puff z-pinch reported by Kroupp et al. [Phys. Rev. Lett. 107, 105001 (2011)]. Calculations are performed using a 2D, radiation-magnetohydrodynamic code with Tabular Collisional-Radiative Equilibrium, namely Mach2-TCRE [Thornhill et al., Phys. Plasmas 8, 3480 (2001)]. The extensive data set of imaging and K-shell spectroscopy from the experiments provides a challenging validation test for z-pinch simulations. Synthetic visible images of the implosion phase match the observed large scale structure if the breakdown occurs at the density corresponding to the Paschen minimum. At the beginning of stagnation (−4 ns), computed plasma conditions change rapidly showing a rising electron density and a peak in the ion thermal temperature of ∼1.8 keV. This is larger than the ion thermal temperature (<400 eV) inferred from the experiment. By the time of peak K-shell power (0 ns), the calculated electron density is similar to the data and the electron and ion thermal temperatures are equilibrated, as is observed. Effective ion temperatures are obtained from calculated emission line widths accounting for thermal broadening and Doppler velocity shifts. The observed, large effective ion temperatures (∼4 keV) early in the stagnation of this Ne pinch can be explained solely as a combination of compressional ion heating and steep radial velocity gradients near the axis. Approximations in the modeling are discussed in regard to the higher ion thermal temperature and lower electron density early in the stagnation compared to the experimental results.

  14. Magnetohydrodynamic simulation of solid-deuterium-initiated Z-pinch experiments

    SciTech Connect

    Sheehey, P.T.

    1994-02-01

    Solid-deuterium-initiated Z-pinch experiments are numerically simulated using a two-dimensional resistive magnetohydrodynamic model, which includes many important experimental details, such as ``cold-start`` initial conditions, thermal conduction, radiative energy loss, actual discharge current vs. time, and grids of sufficient size and resolution to allow realistic development of the plasma. The alternating-direction-implicit numerical technique used meets the substantial demands presented by such a computational task. Simulations of fiber-initiated experiments show that when the fiber becomes fully ionized rapidly developing m=0 instabilities, which originated in the coronal plasma generated from the ablating fiber, drive intense non-uniform heating and rapid expansion of the plasma column. The possibility that inclusion of additional physical effects would improve stability is explored. Finite-Larmor-radius-ordered Hall and diamagnetic pressure terms in the magnetic field evolution equation, corresponding energy equation terms, and separate ion and electron energy equations are included; these do not change the basic results. Model diagnostics, such as shadowgrams and interferograms, generated from simulation results, are in good agreement with experiment. Two alternative experimental approaches are explored: high-current magnetic implosion of hollow cylindrical deuterium shells, and ``plasma-on-wire`` (POW) implosion of low-density plasma onto a central deuterium fiber. By minimizing instability problems, these techniques may allow attainment of higher temperatures and densities than possible with bare fiber-initiated Z-pinches. Conditions for significant D-D or D-T fusion neutron production may be realizable with these implosion-based approaches.

  15. A compact soft X-ray microscope using an electrode-less Z-pinch source

    NASA Astrophysics Data System (ADS)

    Horne, S. F.; Silterra, J.; Holber, W.

    2009-09-01

    Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported. (Supported by NIH grants 5R44RR022488-03 and 5R44RR023753-03)

  16. Implosion dynamics and x-ray generation in small-diameter wire-array Z pinches.

    PubMed

    Ivanov, V V; Sotnikov, V I; Kindel, J M; Hakel, P; Mancini, R C; Astanovitskiy, A L; Haboub, A; Altemara, S D; Shevelko, A P; Kazakov, E D; Sasorov, P V

    2009-05-01

    It is known from experiments that the radiated x-ray energy appears to exceed the calculated implosion kinetic energy and Spitzer resistive heating [C. Deeney, Phys. Rev. A 44, 6762 (1991)] but possible mechanisms of the enhanced x-ray production are still being discussed. Enhanced plasma heating in small-diameter wire arrays with decreased calculated kinetic energy was investigated, and a review of experiments with cylindrical arrays of 1-16 mm in diameter on the 1 MA Zebra generator is presented in this paper. The implosion and x-ray generation in cylindrical wire arrays with different diameters were compared to find a transition from a regime where thermalization of the kinetic energy is the prevailing heating mechanism to regimes with other dominant mechanisms of plasma heating. Loads of 3-8 mm in diameter generate the highest x-ray power at the Zebra generator. The x-ray power falls in 1-2 mm loads which can be linked to the lower efficiency of plasma heating with the lack of kinetic energy. The electron temperature and density of the pinches also depend on the array diameter. In small-diameter arrays, 1-3 mm in diameter, ablating plasma accumulates in the inner volume much faster than in loads of 12-16 mm in diameter. Correlated bubblelike implosions were observed with multiframe shadowgraphy. Investigation of energy balance provides evidence for mechanisms of nonkinetic plasma heating in Z pinches. Formation and evolution of bright spots in Z pinches were studied with a time-gated pinhole camera. A comparison of x-ray images with shadowgrams shows that implosion bubbles can initiate bright spots in the pinch. Features of the implosions in small-diameter wire arrays are discussed to identify mechanisms of energy dissipation.

  17. Digital holographic interferometry employing Fresnel transform reconstruction for the study of flow shear stabilized Z-pinch plasmas

    NASA Astrophysics Data System (ADS)

    Ross, M. P.; Shumlak, U.

    2016-10-01

    The ZaP-HD flow Z-pinch project provides a platform to explore how shear flow stabilized Z-pinches could scale to high-energy-density plasma (plasma with pressures exceeding 1 Mbar) and fusion reactor conditions. The Z-pinch is a linear plasma confinement geometry in which the plasma carries axial electric current and is confined by its self-induced magnetic field. ZaP-HD generates shear stabilized, axisymmetric Z-pinches with stable lifetimes approaching 60 μs. The goal of the project is to increase the plasma density and temperature compared to the previous ZaP project by compressing the plasma to smaller radii (≈1 mm). Radial and axial plasma electron density structure is measured using digital holographic interferometry (DHI), which provides the necessary fine spatial resolution. ZaP-HD's DHI system uses a 2 ns Nd:YAG laser pulse with a second harmonic generator (λ = 532 nm) to produce holograms recorded by a Nikon D3200 digital camera. The holograms are numerically reconstructed with the Fresnel transform reconstruction method to obtain the phase shift caused by the interaction of the laser beam with the plasma. This provides a two-dimensional map of line-integrated electron density, which can be Abel inverted to determine the local number density. The DHI resolves line-integrated densities down to 3 × 1020 m-2 with spatial resolution near 10 μm. This paper presents the first application of Fresnel transform reconstruction as an analysis technique for a plasma diagnostic, and it analyzes the method's accuracy through study of synthetic data. It then presents an Abel inversion procedure that utilizes data on both sides of a Z-pinch local number density profile to maximize profile symmetry. Error estimation and Abel inversion are applied to the measured data.

  18. Characterization of plasma expansion dynamics in a high power diode with a carbon-fiber-aluminum cathode

    SciTech Connect

    Ju, J.-C.; Liu, L.; Cai, D.

    2014-06-09

    Thermal plasma expansion is characterised during the operation of a high power diode with an explosive emission carbon-fiber-aluminum cathode driven by a 250 kV, 150 ns accelerating pulse. It is found that a quasi-stationary state of plasma expansion is obtained during the main part of the accelerating pulse and the whole plasma expansion exhibits an “U”-shape velocity evolution. A theoretical model describing the dynamics of plasma expansion is developed, which indicates that the plasma expansion velocity is determined by equilibrium between the diode current density and plasma thermal electron current density.

  19. Methods and results of studies of the radiation spectra of megampere Z-pinches at the angara-5-1 facility

    NASA Astrophysics Data System (ADS)

    Boldarev, A. S.; Bolkhovitinov, E. A.; Vichev, I. Yu.; Volkov, G. S.; Gasilov, V. A.; Grabovskii, E. V.; Gritsuk, A. N.; Dan'ko, S. A.; Zaitsev, V. I.; Novikov, V. G.; Oleinik, G. M.; Ol'khovskaya, O. G.; Rupasov, A. A.; Fedulov, M. V.; Shikanov, A. S.

    2015-02-01

    Methods and results of studies of the radiation spectra of high-current Z-pinches with different elemental compositions are presented. To examine a wide spectral range ( E hν = 30-3000 eV), two diagnostics tools were used—a transmission grating and a reflecting mica crystal. The radiation characteristics of the pinch are determined by its elemental composition. For currents of 2-3 MA and low- Z elements (aluminum), the hard end of the radiation spectrum is represented by spectral lines with clearly pronounced K lines, while for high- Z elements (tungsten), the spectrum lies in the softer photon energy range and is quasi-continuous. Two methods of spectrum processing were used to determine the plasma parameters. The parameters of aluminum plasma were traditionally determined from the intensity ratios of the K lines taking into account the plasma transparency for these lines. The spectra of tungsten plasma were compared with the results of computer simulations of pinch compression with allowance for both magnetohydrodynamic and plasma radiation processes. The applicability of these methods of spectral analysis is discussed.

  20. Methods and results of studies of the radiation spectra of megampere Z-pinches at the angara-5-1 facility

    SciTech Connect

    Boldarev, A. S.; Bolkhovitinov, E. A.; Vichev, I. Yu.; Volkov, G. S.; Gasilov, V. A.; Grabovskii, E. V.; Gritsuk, A. N.; Dan’ko, S. A.; Zaitsev, V. I.; Novikov, V. G.; Oleinik, G. M.; Ol’khovskaya, O. G.; Rupasov, A. A.; Fedulov, M. V.; Shikanov, A. S.

    2015-02-15

    Methods and results of studies of the radiation spectra of high-current Z-pinches with different elemental compositions are presented. To examine a wide spectral range (E{sub hν} = 30–3000 eV), two diagnostics tools were used—a transmission grating and a reflecting mica crystal. The radiation characteristics of the pinch are determined by its elemental composition. For currents of 2–3 MA and low-Z elements (aluminum), the hard end of the radiation spectrum is represented by spectral lines with clearly pronounced K lines, while for high-Z elements (tungsten), the spectrum lies in the softer photon energy range and is quasi-continuous. Two methods of spectrum processing were used to determine the plasma parameters. The parameters of aluminum plasma were traditionally determined from the intensity ratios of the K lines taking into account the plasma transparency for these lines. The spectra of tungsten plasma were compared with the results of computer simulations of pinch compression with allowance for both magnetohydrodynamic and plasma radiation processes. The applicability of these methods of spectral analysis is discussed.

  1. Reliable Copper and Aluminum Connections for High Power Applications in Electromobility

    NASA Astrophysics Data System (ADS)

    Hofmann, Konstantin; Holzer, Matthias; Hugger, Florian; Roth, Stephan; Schmidt, Michael

    Investigations concerning the growth of intermetallic phases during the heat input both at the diffusion annealing of copper aluminum roll claddings and the subsequent welding process of copper-aluminum connections by using roll cladded inserts are compared to the analytical determination of phase growth. The temperature distribution in the cladding interface has been determined by thermal simulation, in order to calculate the growth of the intermetallic phases. A comparison between the width of the phases in the analytical calculation and the experiment is achieved. In consideration of high welding speeds, the energy input during the welding process is appraised in order to grade the growth of intermetallic phases. Furthermore the prevention of damage in the roll cladding interface by means of unadapted material thicknesses or welding parameters can be assessed analytically and numerically. The numerical simulations can determine the critical thickness of the roll cladding to avoid damage like exceeding growth of intermetallic phases.

  2. Polarization effects of a high-power CO2 laser beam on aluminum alloy weldability

    NASA Astrophysics Data System (ADS)

    Sato, Shunichi; Takahashi, Kunimitsu; Mehmetli, Bülent

    1996-06-01

    Linearly polarized CO2 laser beams have been used to investigate the effects of polarization on aluminum alloy weldability. Bead-on-plate welding tests have been performed on A5083 (AlMg4.5Mn0.7) alloy plates with quasi-TEM00-mode beams whose polarization direction is parallel or perpendicular to the welding direction, referred to as the parallel or the perpendicular polarization beam, respectively. Comparison of the fusion zone shapes between the two cases shows that deeper penetration, and hence more efficient optical energy coupling to the work can be obtained with the parallel polarization beam. This effect can be interpreted as being due to the higher Fresnel absorption at the keyhole front wall for the parallel polarization beam than for the perpendicular polarization beam. It is also found that the polarization effect is much more evident in the case of He gas shielding than in the case of Ar gas shielding. The weaker polarization effects observed in the case of Ar may be due to more densely formed laser-induced plume or plasma because of lower ionization potential and much smaller thermal conductivity of Ar when compared with those of He. Under such conditions the energy coupling may be dominated by plasma absorption (the inverse bremsstrahlung absorption). It has so far been considered that in aluminum welding, the energy coupling is dominated by the plasma absorption, because relatively strong plasma is observed in aluminum welding. But our results indicate that the Fresnel absorption process has an important role on the energy coupling mechanism under certain conditions.

  3. Properties of the Best Ar K-Shell Radiators: Two Decades of Data Analysis from Seven Z-Pinch Drivers

    SciTech Connect

    Apruzese, J. P.; Commisso, R. J.; Weber, B. V.; Thornhill, J. W.; Giuliani, J. L.; Mosher, D.; Young, F. C.; Coverdale, C. A.; Deeney, C.

    2009-01-21

    Z Pinches formed from Ar gas puffs have been investigated for more than two decades. Experiments have been performed on many generators; a frequent objective has been maximization of the yield in the K-shell lines. The increase in available current during that time, from 2 to 15 MA, has resulted in a remarkable enhancement in yield from a few kJ on PITHON to {approx}300 kJ on Sandia's Z generator. We have analyzed spectroscopic and other radiation data from seven Z-pinch drivers, some dating back to 1991, in an effort to determine what properties of the pinches correlate with high K-shell yield. The strongest correlation is with the amount of mass that is heated to K-shell emitting temperatures. Those temperatures, effective at emitting Ar K-shell x rays, exhibit a range of {approx}1 to 2.4 keV.

  4. Transition from Beam-Target to Thermonuclear Fusion in High-Current Deuterium Z-Pinch Simulations.

    PubMed

    Offermann, Dustin T; Welch, Dale R; Rose, Dave V; Thoma, Carsten; Clark, Robert E; Mostrom, Chris B; Schmidt, Andrea E W; Link, Anthony J

    2016-05-13

    Fusion yields from dense, Z-pinch plasmas are known to scale with the drive current, which is favorable for many potential applications. Decades of experimental studies, however, show an unexplained drop in yield for currents above a few mega-ampere (MA). In this work, simulations of DD Z-Pinch plasmas have been performed in 1D and 2D for a constant pinch time and initial radius using the code Lsp, and observations of a shift in scaling are presented. The results show that yields below 3 MA are enhanced relative to pure thermonuclear scaling by beamlike particles accelerated in the Rayleigh-Taylor induced electric fields, while yields above 3 MA are reduced because of energy lost by the instability and the inability of the beamlike ions to enter the pinch region.

  5. Analyses in Support of Z-Pinch IFE and Actinide Transmutation - LLNL Progress Report for FY-06

    SciTech Connect

    Meier, W R; Moir, R W; Abbott, R

    2006-09-19

    This report documents results of LLNL's work in support of two studies being conducted by Sandia National Laboratories (SNL): the development of the Z-pinch driven inertial fusion energy (Z-IFE), and the use of Z-pinch driven inertial fusion as a neutron source to destroy actinides from fission reactor spent fuel. LLNL's efforts in FY06 included: (1) Development of a systems code for Z-IFE and use of the code to examine the operating parameter space in terms of design variables such as the Z-pinch driver energy, the chamber pulse repetition rate, the number of chambers making up the power plant, and the total net electric power of the plant. This is covered in Section 3 with full documentation of the model in Appendix A. (2) Continued development of innovative concepts for the design and operation of the recyclable transmission line (RTL) and chamber for Z-IFE. The work, which builds on our FY04 and FY05 contributions, emphasizes design features that are likely to lead to a more attractive power plant including: liquid jets to protect all structures from direct exposure to neutrons, rapid insertion of the RTL to maximize the potential chamber rep-rate, and use of cast flibe for the RTL to reduce recycling and remanufacturing costs and power needs. See Section 4 and Appendix B. (3) Description of potential figures of merit (FOMs) for actinide transmutation technologies and a discussion of how these FOMs apply and can be used in the ongoing evaluation of the Z-pinch actinide burner, referred to as the In-Zinerator. See Section 5. (4) A critique of, and suggested improvements to, the In-Zinerator chamber design in response to the SNL design team's request for feedback on its preliminary design. This is covered in Section 6.

  6. Comments on the critical issues for a high-density gas-embedded Z-pinch CTR reactor concept

    NASA Astrophysics Data System (ADS)

    Ekdahl, C. A.

    1981-02-01

    The issues considered critical for the realization of a CTR reactor are discussed for the high density gas embedded z pinch concept. A simple model of the pinch reactor is presented that gives estimates for Q in substantial agreement with elaborate computer studies. An attempt is made to identify such critical points that are amenable to exploratory experiments. There appears to be no fatal flaw in the issues covered that would preclude a viable reactor based on this concept.

  7. Computational investigation of the limits to Pease-Braginskii collapse of a Z-pinch

    SciTech Connect

    Nielsen, P.D.

    1981-06-01

    This dissertation investigates the one-dimensional limits to such a radiation enhanced collapse through the use of a Lagrangian simulation code, LASNEX. The code includes the effects of a wide range of phenomena - opacity, ionization, experimentally determined equations of state, magnetic effects on transport coefficients, and external electrical circuits. Special attention was given to the magnetic field subroutines. They were revised to include ion acoustic and lower hybrid drift induced resistivity and to increase accuracy and efficiency. The magnetic pressure term was differenced in a manner that eliminates any influence of zone size, allowing large, low density zones outside the plasma column. In these large zones, magnetic flux and energy were determined by direct integration instead of summation to increase overall conservation. With these changes, the computational timesteps were determined by phenomena in the plasma instead of the Alfven velocity in the low density region. These modifications improved the accuracy of the code on Z-pinch problems by a factor of 10-100 depending on the minimum pinch radius reached.

  8. Measurements of high energy photons in Z-pinch experiments on primary test stand

    SciTech Connect

    Si, Fenni Zhang, Chuanfei; Xu, Rongkun; Yuan, Xi; Huang, Zhanchang; Xu, Zeping; Ye, Fan; Yang, Jianlun; Ning, Jiamin; Hu, Qingyuan; Zhu, Xuebin

    2015-08-15

    High energy photons are measured for the first time in wire-array Z-pinch experiments on the Primary Test Stand (PTS) which delivers a current up to 8 MA with a rise time of 70 ns. A special designed detecting system composed of three types of detectors is used to measure the average energy, intensity, and pulse waveform of high energy photons. Results from Pb-TLD (thermoluminescence dosimeter) detector indicate that the average energy is 480 keV (±15%). Pulse shape of high energy photons is measured by the photodiode detector consisted of scintillator coupled with a photodiode, and it is correlated with soft x-ray power by the same timing signal. Intensity is measured by both TLD and the photodiode detector, showing good accordance with each other, and it is 10{sup 10} cm{sup −2} (±20%) at 2 m in the horizontal direction. Measurement results show that high energy photons are mainly produced in pinch regions due to accelerated electrons. PTS itself also produces high energy photons due to power flow electrons, which is one order smaller in amplitude than those from pinch region.

  9. Effect of driver impedance on dense plasma focus Z-pinch neutron yield

    SciTech Connect

    Sears, Jason E-mail: schmidt36@llnl.gov; Link, Anthony E-mail: schmidt36@llnl.gov; Schmidt, Andrea E-mail: schmidt36@llnl.gov; Welch, Dale

    2014-12-15

    The Z-pinch phase of a dense plasma focus (DPF) heats the plasma by rapid compression and accelerates ions across its intense electric fields, producing neutrons through both thermonuclear and beam-target fusion. Driver characteristics have empirically been shown to affect performance, as measured by neutron yield per unit of stored energy. We are exploring the effect of driver characteristics on DPF performance using particle-in-cell (PIC) simulations of a kJ scale DPF. In this work, our PIC simulations are fluid for the run-down phase and transition to fully kinetic for the pinch phase, capturing kinetic instabilities, anomalous resistivity, and beam formation during the pinch. The anode-cathode boundary is driven by a circuit model of the capacitive driver, including system inductance, the load of the railgap switches, the guard resistors, and the coaxial transmission line parameters. It is known that the driver impedance plays an important role in the neutron yield: first, it sets the peak current achieved at pinch time; and second, it affects how much current continues to flow through the pinch when the pinch inductance and resistance suddenly increase. Here we show from fully kinetic simulations how total neutron yield depends on the impedance of the driver and the distributed parameters of the transmission circuit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for neutron source applications.

  10. New compact hohlraum configuration research at the 1.7 MA Z-pinch generator

    SciTech Connect

    Kantsyrev, V. L. Shrestha, I. K.; Esaulov, A. A.; Safronova, A. S.; Shlyaptseva, V. V.; Osborne, G. C.; Astanovitsky, A. L.; Weller, M. E.; Stafford, A.; Schultz, K. A.; Cooper, M. C.; Chuvatin, A. S.; Rudakov, L. I.; Velikovich, A. L.; Cuneo, M. E.; Jones, B.; Vesey, R. A.

    2014-12-15

    A new compact Z-pinch x-ray hohlraum design with parallel-driven x-ray sources was experimentally demonstrated in a full configuration with a central target and tailored shine shields (to provide a symmetric temperature distribution on the target) at the 1.7 MA Zebra generator. This presentation reports on the joint success of two independent lines of research. One of these was the development of new sources – planar wire arrays (PWAs). PWAs turned out to be a prolific radiator. Another success was the drastic improvement in energy efficiency of pulsed-power systems, such as the Load Current Multiplier (LCM). The Zebra/LCM generator almost doubled the plasma load current to 1.7 MA. The two above-mentioned innovative approaches were used in combination to produce a new compact hohlraum design for ICF, as jointly proposed by SNL and UNR. Good agreement between simulated and measured radiation temperature of the central target is shown. Experimental comparison of PWAs with planar foil liners (PFL) - another viable alternative to wire array loads at multi-MA generators show promising data. Results of research at the University of Nevada Reno allowed for the study of hohlraum coupling physics at University-scale generators. The advantages of new hohlraum design applications for multi-MA facilities with W or Au double PWAs or PFL x-ray sources are discussed.

  11. Quasi-steady accelerator operation on the ZAP flow Z-pinch

    NASA Astrophysics Data System (ADS)

    Hughes, M. C.; Shumlak, U.; Golingo, R. P.; Nelson, B. A.; Ross, M. P.

    2014-12-01

    The ZaP Flow Z-Pinch Experiment utilizes sheared flows to stabilize an otherwise unstable equilibrium. The sheared flows are maintained by streaming high velocity plasma parallel to the pinch. Previous operations of the machine show depletion of the accelerator's neutral gas supply late in the pulse leading to pinch instability. The current distribution in the accelerator exhibits characteristic modes during this operation, which is corroborated by interferometric signals. The decrease in density precipitates a loss of plasma quiescence in the pinch, which occurs on a timescale related to the flow velocity from the plasma source. To abate the depletion, the geometry of the accelerator is altered to increase the neutral gas supply. The design creates a standing deflagration front in the accelerator that persists for the pulse duration. The new operating mode is characterized by the same diagnostics as the previous mode. The lessons learned in the accelerator operations have been applied to the design of a new experiment, ZaP-HD. This work was supported by grants from the Department of Energy and the National Nuclear Security Administration.

  12. Effect of driver impedance on dense plasma focus Z-pinch neutron yield

    NASA Astrophysics Data System (ADS)

    Sears, Jason; Link, Anthony; Schmidt, Andrea; Welch, Dale

    2014-12-01

    The Z-pinch phase of a dense plasma focus (DPF) heats the plasma by rapid compression and accelerates ions across its intense electric fields, producing neutrons through both thermonuclear and beam-target fusion. Driver characteristics have empirically been shown to affect performance, as measured by neutron yield per unit of stored energy. We are exploring the effect of driver characteristics on DPF performance using particle-in-cell (PIC) simulations of a kJ scale DPF. In this work, our PIC simulations are fluid for the run-down phase and transition to fully kinetic for the pinch phase, capturing kinetic instabilities, anomalous resistivity, and beam formation during the pinch. The anode-cathode boundary is driven by a circuit model of the capacitive driver, including system inductance, the load of the railgap switches, the guard resistors, and the coaxial transmission line parameters. It is known that the driver impedance plays an important role in the neutron yield: first, it sets the peak current achieved at pinch time; and second, it affects how much current continues to flow through the pinch when the pinch inductance and resistance suddenly increase. Here we show from fully kinetic simulations how total neutron yield depends on the impedance of the driver and the distributed parameters of the transmission circuit. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability for neutron source applications.

  13. Neutron spectra from beam-target reactions in dense Z-pinches

    SciTech Connect

    Appelbe, B. Chittenden, J.

    2015-10-15

    The energy spectrum of neutrons emitted by a range of deuterium and deuterium-tritium Z-pinch devices is investigated computationally using a hybrid kinetic-MHD model. 3D MHD simulations are used to model the implosion, stagnation, and break-up of dense plasma focus devices at currents of 70 kA, 500 kA, and 2 MA and also a 15 MA gas puff. Instabilities in the MHD simulations generate large electric and magnetic fields, which accelerate ions during the stagnation and break-up phases. A kinetic model is used to calculate the trajectories of these ions and the neutron spectra produced due to the interaction of these ions with the background plasma. It is found that these beam-target neutron spectra are sensitive to the electric and magnetic fields at stagnation resulting in significant differences in the spectra emitted by each device. Most notably, magnetization of the accelerated ions causes the beam-target spectra to be isotropic for the gas puff simulations. It is also shown that beam-target spectra can have a peak intensity located at a lower energy than the peak intensity of a thermonuclear spectrum. A number of other differences in the shapes of beam-target and thermonuclear spectra are also observed for each device. Finally, significant differences between the shapes of beam-target DD and DT neutron spectra, due to differences in the reaction cross-sections, are illustrated.

  14. Preradiation studies for non-thermal Z-pinch wire load experiments on Saturn

    SciTech Connect

    Sanford, T.W.L.; Humphreys, D.R.; Poukey, J.W.; Marder, B.M.; Halbleib, J.A.; Crow, J.T.; Spielman, R.B.; Mock, R.C.

    1994-06-01

    The implosion dynamics of compact wire arrays on Saturn are explored as a function of wire mass m, wire length {ell}, wire radii R, and radial power-flow feed geometry using the ZORK code. Electron losses and the likelihood of arcing in the radial feed adjacent the wire load are analyzed using the TWOQUICK and CYLTRAN codes. The physical characteristics of the implosion and subsequent thermal radiation production are estimated using the LASNEX code in one dimension. These analyses show that compact tungsten wire arrays with parameters suggested by D. Mosher and with a 21-nH vacuum feed geometry satisfy the empirical scaling criterion I/(M/{ell}) {approximately} 2 MA/(mg/cm) of Mosher for optimizing non-thermal radiation from z pinches, generate low electron losses in the radial feeds, and generate electric fields at the insulator stack below the Charlie Martin flashover limit thereby permitting full power to be delivered to the load. Under such conditions, peak currents of {approximately}5 MA can be delivered to wire loads {approximately}20 ns before the driving voltage reverses at the insulator stack, potentially allowing the m = 0 instability to develop with the subsequent emission of non-thermal radiation as predicted by the Mosher model.

  15. NUMERICAL SIMULATIONS OF Z-PINCH EXPERIMENTS TO CREATE SUPERSONIC DIFFERENTIALLY ROTATING PLASMA FLOWS

    SciTech Connect

    Bocchi, M.; Ummels, B.; Chittenden, J. P.; Lebedev, S. V.; Frank, A.; Blackman, E. G.

    2013-04-10

    The physics of accretion disks is of fundamental importance for understanding of a wide variety of astrophysical sources that includes protostars, X-ray binaries, and active galactic nuclei. The interplay between hydrodynamic flows and magnetic fields and the potential for turbulence-producing instabilities is a topic of active research that would benefit from the support of dedicated experimental studies. Such efforts are in their infancy, but in an effort to push the enterprise forward we propose an experimental configuration which employs a modified cylindrical wire array Z-pinch to produce a rotating plasma flow relevant to accretion disks. We present three-dimensional resistive magnetohydrodynamic simulations which show how this approach can be implemented. In the simulations, a rotating plasma cylinder or ring is formed, with typical rotation velocity {approx}30 km s{sup -1}, Mach number {approx}4, and Reynolds number in excess of 10{sup 7}. The plasma is also differentially rotating. Implementation of different external magnetic field configurations is discussed. It is found that a modest uniform vertical field of 1 T can affect the dynamics of the system and could be used to study magnetic field entrainment and amplification through differential rotation. A dipolar field potentially relevant to the study of accretion columns is also considered.

  16. Characterisation of the current switch mechanism in two-stage wire array Z-pinches

    SciTech Connect

    Burdiak, G. C.; Lebedev, S. V.; Harvey-Thompson, A. J.; Hall, G. N.; Swadling, G. F.; Suzuki-Vidal, F.; Khoory, E.; Bland, S. N.; Pickworth, L.; Grouchy, P. de; Skidmore, J.; Suttle, L.; Waisman, E. M.

    2015-11-15

    In this paper, we describe the operation of a two-stage wire array z-pinch driven by the 1.4 MA, 240 ns rise-time Magpie pulsed-power device at Imperial College London. In this setup, an inverse wire array acts as a fast current switch, delivering a current pre-pulse into a cylindrical load wire array, before rapidly switching the majority of the generator current into the load after a 100–150 ns dwell time. A detailed analysis of the evolution of the load array during the pre-pulse is presented. Measurements of the load resistivity and energy deposition suggest significant bulk heating of the array mass occurs. The ∼5 kA pre-pulse delivers ∼0.8 J of energy to the load, leaving it in a mixed, predominantly liquid-vapour state. The main current switch occurs as the inverse array begins to explode and plasma expands into the load region. Electrical and imaging diagnostics indicate that the main current switch may evolve in part as a plasma flow switch, driven by the expansion of a magnetic cavity and plasma bubble along the length of the load array. Analysis of implosion trajectories suggests that approximately 1 MA switches into the load in 100 ns, corresponding to a doubling of the generator dI/dt. Potential scaling of the device to higher current machines is discussed.

  17. Use of microsecond current prepulse for dramatic improvements of wire array Z-pinch implosion

    NASA Astrophysics Data System (ADS)

    Calamy, H.; Lassalle, F.; Loyen, A.; Zucchini, F.; Chittenden, J. P.; Hamann, F.; Maury, P.; Georges, A.; Bedoch, J. P.; Morell, A.

    2008-01-01

    The Sphinx machine [F. Lassalle et al., "Status on the SPHINX machine based on the 1microsecond LTD technology"] based on microsecond linear transformer driver (LTD) technology is used to implode an aluminium wire array with an outer diameter up to 140mm and maximum current from 3.5to5MA. 700to800ns implosion Z-pinch experiments are performed on this driver essentially with aluminium. Best results obtained before the improvement described in this paper were 1-3TW radial total power, 100-300kJ total yield, and 20-30kJ energy above 1keV. An auxiliary generator was added to the Sphinx machine in order to allow a multi microsecond current to be injected through the wire array load before the start of the main current. Amplitude and duration of this current prepulse are adjustable, with maxima ˜10kA and 50μs. This prepulse dramatically changes the ablation phase leading to an improvement of the axial homogeneity of both the implosion and the final radiating column. Total power was multiplied by a factor of 6, total yield by a factor of 2.5 with a reproducible behavior. This paper presents experimental results, magnetohydrodynamic simulations, and analysis of the effect of such a long current prepulse.

  18. Inward radial transport in differentially rotated plasma discs formed in z-pinch experiments

    NASA Astrophysics Data System (ADS)

    Lebedev, Sergey; Bennett, M.; Swadling, G. F.; Suttle, L.; Blackman, E.; Burdiak, G.; Chittenden, J. P.; Ciardi, A.; Drake, R. P.; Frank, A.; Hall, G. N.; Hare, J.; Patankar, S.; Smith, R. A.; Suzuki-Vidal, F.

    2014-10-01

    We will present experimental results showing the development of instabilities and an inward transport of matter in a differentially rotating supersonic plasma disc with dimensionless parameters relevant to modeling physics of astrophysical discs. The converging off-axis plasma flow forming the disc is produced by ablation of wires in a cylindrical wire array z-pinch (1.4 MA, 250 ns) combined with a cusp magnetic field, and the rotating disc is supported in equilibrium by the ram pressure of the flow. The radial profile of rotation velocity in the disc is measured using Doppler shifts of the ion feature of Thomson scattering spectra, while the broadening of the spectra yields the plasma temperature. The evolution of the disc structure is observed with multi-frame XUV and optical cameras, and the plasma density is measured using end-on laser interferometry. The Reynolds number in the disc is sufficiently large (>105) to allow development of turbulence on the time-scale of the experiment, and the observed inward transport of matter with the growth of small scale structures suggests that turbulence is responsible for the transport.

  19. Quasi-steady accelerator operation on the ZAP flow Z-pinch

    SciTech Connect

    Hughes, M. C. Shumlak, U. Golingo, R. P. Nelson, B. A. Ross, M. P.

    2014-12-15

    The ZaP Flow Z-Pinch Experiment utilizes sheared flows to stabilize an otherwise unstable equilibrium. The sheared flows are maintained by streaming high velocity plasma parallel to the pinch. Previous operations of the machine show depletion of the accelerator’s neutral gas supply late in the pulse leading to pinch instability. The current distribution in the accelerator exhibits characteristic modes during this operation, which is corroborated by interferometric signals. The decrease in density precipitates a loss of plasma quiescence in the pinch, which occurs on a timescale related to the flow velocity from the plasma source. To abate the depletion, the geometry of the accelerator is altered to increase the neutral gas supply. The design creates a standing deflagration front in the accelerator that persists for the pulse duration. The new operating mode is characterized by the same diagnostics as the previous mode. The lessons learned in the accelerator operations have been applied to the design of a new experiment, ZaP-HD. This work was supported by grants from the Department of Energy and the National Nuclear Security Administration.

  20. Scaling the Shear-flow Stabilized Z-pinch to Reactor Conditions

    NASA Astrophysics Data System (ADS)

    McLean, H. S.; Schmidt, A.; Shumlak, U.; Nelson, B. A.; Golingo, R. P.; Cleveau, E.

    2015-11-01

    We present a conceptual design along with scaling calculations for a pulsed fusion reactor based on the shear-flow-stabilized Z-pinch device. Experiments performed on the ZaP device, at the University of Washington, have demonstrated stable operation for durations of 20 usec at ~100kA discharge current for pinches that are ~1 cm in diameter and 100 cm long. The inverse of the pinch diameter and plasma energy density scale strongly with pinch current and calculations show that maintaining stabilization durations of ~7 usec for increased discharge current (~15x) in a shortened pinch (10 cm) results in a pinch diameter of ~200 um and plasma conditions that approach those needed to support significant fusion burn and energy gain (Ti ~ 30keV, density ~ 3e26/m3, ntau ~1.4e20 sec/m3). Compelling features of the concept include operation at modest discharge current (1.5 MA) and voltage (40kV) along with direct adoption of liquid metals for at least one electrode--technological capabilities that have been proven in existing, commercial, pulse power devices such as large ignitrons. LLNL-ABS-674920. This work performed under the auspices of the U.S. Department of Energy ARPAe ALPHA Program by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. Ion viscous heating in a magnetohydrodynamically unstable Z-pinch at over two billion Kelvin.

    SciTech Connect

    Jones, Brent Manley; Coverdale, Christine Anne; LePell, Paul David; Haines, Malcolm G.; Deeney, Christopher

    2005-02-01

    Pulsed power driven metallic wire-array Z pinches are the most powerful and efficient laboratory x-ray sources. Furthermore, under certain conditions the soft x-ray energy radiated in a 5 ns pulse at stagnation can exceed the estimated kinetic energy of the radial implosion phase by a factor of 3 to 4. A theoretical model is developed here to explain this, allowing the rapid conversion of magnetic energy to a very high ion temperature plasma through the generation of fine scale, fast-growing m=0 interchange MHD instabilities at stagnation. These saturate nonlinearly and provide associated ion viscous heating. Next the ion energy is transferred by equipartition to the electrons and thus to soft x-ray radiation. Recent time-resolved iron spectra at Sandia confirm an ion temperature T{sub i} of over 200 keV (2 x 10{sup 9} degrees), as predicted by theory. These are believed to be record temperatures for a magnetically confined plasma.

  2. Z-pinch diagnostics, plasma and liner instabilities and new x-ray techniques

    SciTech Connect

    Oona, H.; Anderson, B.; Benage, J.

    1996-09-01

    Pulse power experiments of the last several decades have contributed greatly to the understanding of high temperature and high density plasmas and, more recently, to the study of hydrodynamic effects in thick imploding cylinders. Common to all these experiments is the application of a large current pulse to a cylindrically symmetric load, with the resulting Lorenz force compressing the load to produce hydrodynamic motion and/or high temperature, high density plasma. In Los Alamos, Pulsed power experiments are carried out at two facilities. Experiments at low current (from several million to ten million Amperes) are conducted on the Pegasus II capacitor bank. Experiments with higher currents (10`s to 100`s MA range) are performed in Ancho Canyon with the explosively driven Procyon and MAGO magnetic flux compression generator systems. In this paper, the authors present a survey of diagnostic capabilities and results from several sets of experiments. First, they discuss the initiation and growth of instabilities in plasmas generated from the implosion of hollow z-pinches in the pegasus and Procyon experiments. Next they discuss spectroscopic data from the plasmas produced by the MAGO system. They also show time resolved imaging data from thick ({approximately} .4 mm) liner implosions. Finally, the authors discuss improvements to x-ray and visible light imaging and spectrographic diagnostic techniques. The emphasis of this paper is not so much a detailed discussion of the experiments, but a presentation of imaging and spectroscopic results and the implications of these observations to the experiments.

  3. The role of Z-pinches and related configurations in magnetized target fusion

    SciTech Connect

    Lindemuth, I.R.

    1997-07-10

    The use of a magnetic field within a fusion target is now known as Magnetized Target Fusion in the US and as MAGO (Magnitnoye Obzhatiye, or magnetic compression) in Russia. In contrast to direct, hydrodynamic compression of initially ambient-temperature fuel (e.g., ICF), MTF involves two steps: (a) formation of a warm, magnetized, wall-confined plasma of intermediate density within a fusion target prior to implosion; (b) subsequent quasi-adiabatic compression and heating of the plasma by imploding the confining wall, or pusher. In many ways, MTF can be considered a marriage between the more mature MFE and ICF approaches, and this marriage potentially eliminates some of the hurdles encountered in the other approaches. When compared to ICF, MTF requires lower implosion velocity, lower initial density, significantly lower radial convergence, and larger targets, all of which lead to substantially reduced driver intensity, power, and symmetry requirements. When compared to MFE, MTF does not require a vacuum separating the plasma from the wall, and, in fact, complete magnetic confinement, even if possible, may not be desirable. The higher density of MTF and much shorter confinement times should make magnetized plasma formation a much less difficult step than in MFE. The substantially lower driver requirements and implosion velocity of MTF make z-pinch magnetically driven liners, magnetically imploded by existing modern pulsed power electrical current sources, a leading candidate for the target pusher of an MTF system.

  4. Development of the Axial Instability in Low Wire Number Wire Array Z-Pinches

    NASA Astrophysics Data System (ADS)

    Knapp, P. F.; Bell, K. S.; Blesener, I. C.; Chalenski, D. A.; Greenly, J. B.; Martin, M. R.; McBride, R. D.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Kusse, B. R.

    2008-11-01

    We are investigating the development of the axial instability that occurs on wires in wire-array Z-pinches, which manifests itself as a modulation of the size of the coronal plasma. The modulation is evidently a result of non-uniform ablation of material from the wire core. It is known that the wavelength of this modulation reaches a constant as the pinch develops that is a strong function of the material and little else, thus it is known as the fundamental mode. In these experiments we have been imaging individual wires with laser shadowgraphy primarily in low wire number, large wire diameter arrays made with Al, Cu, Ag and other wires. We document the development of this modulation from the beginning of plasma formation and show the wavelength and amplitude growth as a function of time. The magnetic field is also measured using B-dot probes inside the array. The change from a closed to an open field topology and its relation to the instability growth will be discussed.This research was supported by the Stewardship Sciences Academic Alliances program of the National Nuclear Security Administration under DOE Cooperative agreement DE-FC03-02NA00057 and by Sandia National Laboratories contract AO258.

  5. The Physics of Long-Pulse Wire Array Z-Pinch Implosions

    SciTech Connect

    DOUGLAS,MELISSA R.; DEENEY,CHRISTOPHER; SPIELMAN,RICK B.; COVERDALE,CHRISTINE A.; RODERICK,N.F.; PETERSON,D.L.

    1999-12-14

    Recent improvements in z-pinch wire array load design at Sandia National Laboratories have led to a substantial increase in pinch performance as measured by radiated powers of up to 280 TW in 4 ns and 1.8 MJ of total radiated energy. Next generation, higher current machines will allow for larger mass arrays and comparable or higher velocity implosions to be reached, possibly extending these result.dis the current is pushed above 20 MA, conventional machine design based on a 100 ns implosion time results in higher voltages, hence higher cost and power flow risk. Another approach, which shifts the risk to the load configuration, is to increase the implosion time to minimize the voltage. This approach is being investigated in a series of experimental campaigns on the Saturn and Z machines. In this paper, both experimental and two dimensional computational modeling of the fist long implosion Z experiments will be presented. The experimental data shows broader pulses, lower powers, and larger pinch diameters compared to the corresponding short pulse data. By employing a nested array configuration, the pinch diameter was reduced by 50% with a corresponding increase in power of > 30%. Numerical simulations suggest load velocity is the dominating mechanism behind these results.

  6. Temperature Evolution of a 1 MA Triple-Nozzle Gas-Puff Z-Pinch

    NASA Astrophysics Data System (ADS)

    de Grouchy, Philip; Banasek, Jacob; Engelbrecht, Joey; Qi, Niansheng; Atoyan, Levon; Byvank, Tom; Cahill, Adam; Moore, Hannah; Potter, William; Ransohoff, Lauren; Hammer, David; Kusse, Bruce; Laboratory of Plasma Studies Team

    2015-11-01

    Mitigation of the Rayleigh-Taylor instability (RTI) plays a critical role in optimizing x-ray output at high-energy ~ 13 keV using the triple-nozzle Krypton gas-puff at Sandia National Laboratory. RTI mitigation by gas-puff density profiling using a triple-nozzle gas-puff valve has recently been recently demonstrated on the COBRA 1MA z-pinch at Cornell University. In support of this work we investigate the role of shell cooling in the growth of RTI during gas-puff implosions. Temperature measurements within the imploding plasma shell are recorded using a 527 nm, 10 GW Thomson scattering diagnostic for Neon, Argon and Krypton puffs. The mass-density profile is held constant at 22 microgram per centimeter for all three puffs and the temperature evolution of the imploding material is recorded. In the case of Argon puffs we find that the shell ion and electron effective temperatures remain in equilibrium at around 1keV for the majority of the implosion phase. In contrast scattered spectra from Krypton are dominated by of order 10 keV effective ion temperatures. Supported by the NNSA Stewardship Sciences Academic Programs.

  7. Use of microsecond current prepulse for dramatic improvements of wire array Z-pinch implosion

    SciTech Connect

    Calamy, H.; Lassalle, F.; Loyen, A.; Zucchini, F.; Chittenden, J. P.; Hamann, F.; Maury, P.; Georges, A.; Bedoch, J. P.; Morell, A.

    2008-01-15

    The Sphinx machine [F. Lassalle et al., 'Status on the SPHINX machine based on the 1microsecond LTD technology'] based on microsecond linear transformer driver (LTD) technology is used to implode an aluminium wire array with an outer diameter up to 140 mm and maximum current from 3.5 to 5 MA. 700 to 800 ns implosion Z-pinch experiments are performed on this driver essentially with aluminium. Best results obtained before the improvement described in this paper were 1-3 TW radial total power, 100-300 kJ total yield, and 20-30 kJ energy above 1 keV. An auxiliary generator was added to the Sphinx machine in order to allow a multi microsecond current to be injected through the wire array load before the start of the main current. Amplitude and duration of this current prepulse are adjustable, with maxima {approx}10 kA and 50 {mu}s. This prepulse dramatically changes the ablation phase leading to an improvement of the axial homogeneity of both the implosion and the final radiating column. Total power was multiplied by a factor of 6, total yield by a factor of 2.5 with a reproducible behavior. This paper presents experimental results, magnetohydrodynamic simulations, and analysis of the effect of such a long current prepulse.

  8. Gas Puff Z-Pinches at 1-MA and 200-ns on COBRA

    NASA Astrophysics Data System (ADS)

    Hammer, David; Qi, Niansheng; Rosenberg, Elliott; Atoyan, Levon; Potter, William; Blesener, Kate; Cahill, Adam; Gourdain, Pierre-Alexandre; Greenly, John; Hoyt, Cad; Kusse, Bruce; Pikuz, Sergei; Schrafel, Peter; Shelkovenko, Tatiana

    2013-10-01

    We report 6-cm diameter, double-shell gas puff Z-pinch experiments at 1 MA on the COBRA pulsed power generator, in which the implosion dynamics in puff-on-puff load configurations with and without a wire on the pinch axis were studied. Diagnostics used included: Planar Laser Induced Fluorescence Analyzer for measuring initial density profiles of the gas puff; a Laser Shearing Interferometer and a Laser Wavefront Analyzer for density profiles in the implosion and pinch phases; fiber-coupled, gated visible-light spectrometers for radially resolved imploding plasma spectra; gated XUV cameras for implosion dynamics; filtered pinhole x-ray cameras for imaging x-ray emission; and a double-crystal x-ray spectrometer for axially resolved pinch plasma densities and temperatures. From these, we derived the implosion velocity, ion charge states and then the imploding plasma temperatures, obtained the time evolution of the imploding plasma sheath structure and Magnetic Rayleigh-Taylor instability, and observed the most stable implosion with light-ions (Ne) imploding on heavy-ions (Ar), unstable implosions with heavy-ions (Ar) imploding on light-ions (Ne), and tighter, denser and less hot pinch plasma with a wire on axis. Details of the results will be presented. Supported by NNSA under DOE Coop. Agreement DE- NA0001836.

  9. Ablation dynamics in wire array Z-pinches under modifications on global magnetic field topology

    SciTech Connect

    Veloso, Felipe Muñoz-Cordovez, Gonzalo; Donoso-Tapia, Luis; Valenzuela-Villaseca, Vicente; Favre, Mario; Wyndham, Edmund; Suzuki-Vidal, Francisco; Swadling, George; Chittenden, Jeremy

    2015-07-15

    The dynamics of ablation streams and precursor plasma in cylindrical wire array Z-pinches under temporal variations of the global magnetic field topology is investigated through experiments and numerical simulations. The wire arrays in these experiments are modified by replacing a pair of consecutive wires with wires of a larger diameter. This modification leads to two separate effects, both of which impact the dynamics of the precursor plasma; firstly, current is unevenly distributed between the wires and secondly, the thicker wires take longer to fully ablate. The uneven distribution of current is evidenced in the experiments by the drift of the precursor off axis due to a variation in the global magnetic field topology which modifies the direction of the ablation streams tracking the precursor position. The variation of the global magnetic field due to the presence of thick wires is studied with three-dimensional magnetohydrodynamic (MHD) simulations, showing that the global field changes from the expected toroidal field to a temporally variable topology after breakages appear in the thin wires. This leads to an observed acceleration of the precursor column towards the region closer to the thick wires and later, when thick wires also present breakages, it continues moving away from the original array position as a complicated and disperse object subject to MHD instabilities.

  10. Analyzing Spatially Resolved Z-pinch Spectra to Determine the Nature of ``Bright Spots''*

    NASA Astrophysics Data System (ADS)

    Apruzese, J. P.; Giuliani, J. L.; Thornhill, J. W.; Ampleford, D. J.; Jones, B.; Coverdale, C. A.

    2011-10-01

    Wire array Z-pinch implosions which access the K-shell stages of their load elements are usually characterized by spatially nonuniform emission. But, is the existence of the ``bright spots'' due to density enhancement, higher temperature, or some combination of the two? Does the answer vary with atomic number of the load? To investigate this issue we have analyzed spatially resolved spectra from Cu and Al pinches driven by the Z generator. Correlation studies and regression analyses from the derived conditions are employed in order to infer the cause(s) of the local enhancements of K-shell powers. Work supported by U. S. Department of Energy, National Nuclear Security Administration. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DOE's NNSA under contract DE-AC04-94AL85000. JPA is a consultant to NRL through L3 Communications, Chantilly, VA 20151.

  11. Investigating the density structure of the ZaP-HD Flow Z-Pinch with digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Ross, Michael; Shumlak, Uri; Nelson, Brian; Golingo, Raymond; Hughes, Michal; Forbes, Eleanor; Paliwoda, Matt

    2014-10-01

    The ZaP-HD Flow Z-Pinch experiment investigates how flow shear stabilized Z-pinches scale to higher densities and temperatures. Determining how such plasmas scale up may reveal their utility as test beds for HEDP physics. Scaling towards HEDP conditions requires compressing the plasma to a smaller size with increased plasma current. Measuring the internal structure of a smaller, hotter plasma requires high-resolution diagnostics. To measure electron density profiles, the ZaP-HD team uses holographic interferometry with 30 micron resolution. A new Nd:YAG laser is employed in concert with a consumer digital camera to record holograms, which are numerically reconstructed to obtain the phase shift caused by the interaction of the laser with the plasma. The numerical reconstruction provides a two-dimensional map of chord-integrated electron density, which can be inverted to radial profiles under the assumption of axisymmetry. Measurements of Z-pinch density structure are presented. This work is supported by grants from the U.S. Department of Energy and the U.S. National Nuclear Security Administration.

  12. Spectroscopic Studies of the Soft X-Ray Radiation from Gas-Puff Z-Pinches on Cobra

    NASA Astrophysics Data System (ADS)

    Shelkovenko, T. A.; Pikuz, S. A.; de Grouchy, P. W. L.; Qi, N.; Atoyan, L.; Kusse, B. R.; Hammer, D. A.

    2015-11-01

    Gas-puff Z-pinch experiments have been conducted on the 0.8-1.2 MA, 100-240 ns pulse duration COBRA pulsed power generator. Triple nozzle gas-puff loads consisting of Ne, Ar and Kr gases in different combination and pressures with pre-ionization were used in the most recent experiments. Photo-conducting diodes (PCDs) and pinhole cameras with different filters were used to study the X-ray timing, intensity and spatial distribution in different energy bands. Spectrographs with spatial and temporal resolution were used to study the soft x-ray radiation from the gas-puff Z-pinches. One spectrograph with two spherically bent mica crystals was used to study radiation with 200 micron spatial resolution and high spectral resolution. An x-ray streak camera with one spherically bent quartz crystal was used to study the x-ray radiation with up to 10 ps temporal resolution. The x-ray spectra were used to estimate spatial and temporal distributions of plasma parameters and determine the intensity of the line and continuum radiation from the Z-pinches plasma. Work supported by the National Nuclear Security Administration Stewardship Sciences Academic Programs under Department of Energy Cooperative Agreement No. DE-NA0001836.

  13. Velocity distribution function of electrons plasma produced by high power laser pulse interacting aluminum target

    NASA Astrophysics Data System (ADS)

    Mahdieh, M. H.; Razi, E. M.

    2010-09-01

    This paper presents the experimental results of studying the distribution function of electrons plasma produced by irradiating aluminum target by nanosecond pulsed laser in vacuum. The laser beam was provided by second harmonic of a Q-switched Nd:YAG pulsed laser with ~10 nsec pulse duration and energy of 70 mJ. A home made Faraday cup was used for detecting the current signal. From analyzing the time of flight (TOF) experimental distribution function was determined. Comparing the experimental distribution function with Maxwell-Boltzamnn and effusion distribution functions, the electron temperature was estimated. From the experimental results, the velocity of maximum electron flux was determined. In this study the influence of the probe position and biasing voltage was investigated. The results show that the velocity of maximum electron flux and associated temperature rises with distance from the target surface. The results also show that effusion distribution function is more appropriate for modeling such plasma.

  14. Characteristics of Al:Mg alloy wire-array z-pinches on the Z generator

    SciTech Connect

    Sanford, T.W.L.; Chandler, G.A.; Deeney, C.

    1998-12-31

    The characteristics of 95% Al:5% Mg alloy wire-array z-pinches formed by the Z generator and their associated x-emission are discussed. The arrays consisted of 180 to 266 wires, with each wire being 20-mm long and mounted at radii of 15, 20, or 25 mm. The implosion time of the loads explored was maintained at {approximately}106 ns by keeping M*R*R constant. M is the array mass that decreased from 7.1 to 4.2 to 2.6 mg as the radius R was increased. Current at the load was measured by B-dot monitors, and piezo-electric pressure gauges. These monitors showed that peak currents of {approximately}19 MA were generated in agreement with Screamer power-flow simulations. The temporally-resolved radiation field was measured by spatially-integrating resistive bolometers, filtered XRDs, and PCDs in 12 discrete channels that spanned the energy range 5 eV to 7 keV. Preliminary analysis indicates that the total radiated energy generated is of the order of 1 MJ and produces a total x-ray power on the order of 65 TW. The K-shell energy yield shows a strong dependence on mass increasing from {approximately}90 to {approximately}200 kJ as the mass decreases from 7.1 to 2.6 mg. Opacity effects are manifested by the share of Mg radiation greatly exceeding its 5% number ratio. Over this range, the associated FWHM of the K-shell emission decreases from 20 to 13 ns and the peak K-shell power increases from 4 to 12 TW, respectively, The x-ray images suggest the presence of a Rayleigh-Taylor instability. Two-dimensional radiation-magnetohydrodynamic simulations in the R-Z plane give insight into the mass distribution arising from this instability.

  15. K-α emission spectroscopic analysis from a Cu Z-pinch

    SciTech Connect

    Dasgupta, A.; Clark, R. W.; Giuliani, J. L.; Ouart, N. D.; Jones, B.; Ampleford, D. J.; Hansen, S. B.

    2013-06-01

    Advances in diagnostic techniques at the Sandia Z-facility have facilitated the production of very detailed spectral data. In particular, data from the copper nested wire-array shot Z1975 provides a wealth of information about the implosion dynamics and ionization history of the pinch. Besides the dominant valence K- and L-shell lines in Z1975 spectra, K-α lines from various ionization stages were also observed. K-shell vacancies can be created from inner-shell excitation and ionization by hot electrons and from photo-ionization by high-energy photons; these vacancies are subsequently filled by Auger decay or resonance fluorescence. The latter process produces the K-α emission. For plasmas in collisional equilibrium, K-α emission usually occurs from highly charged ions due to the high electron temperatures required for appreciable excitation of the K-α transitions. Our simulation of Z1975 was carried out with the NRL 1-D DZAPP non-LTE radiation-hydrodynamics model, and the resulting K- and L-shell synthetic spectra are compared with measured radiation data. Our investigation will focus on K-α generation by both impacting electrons and photons. Synthetic K-α spectra will be generated either by self-consistently calculating the K-shell vacancy production in a full Z-pinch simulation, or by post-processing data from a simulation. The analysis of these K-α lines as well as K- and L-shell emission from valence electrons should provide quantitative information about the dynamics of the pinch plasma.

  16. The quest for a z-pinch based fusion energy source—a historical perspective

    NASA Astrophysics Data System (ADS)

    Sethian, John

    1997-05-01

    Ever since 1958, when Oscar Anderson observed copious neutrons emanating from a "magnetically self-constricted column of deuterium plasma," scientists have attempted to develop the simple linear pinch into a fusion power source. After all, simple calculations show that if one can pass a current of slightly less than 2 million amperes through a stable D-T plasma, then one could achieve not just thermonuclear break-even, but thermonuclear gain. Moreover, several reactor studies have shown that a simple linear pinch could be the basis for a very attractive fusion system. The problem is, of course, that the seemingly simple act of passing 2 MA through a stable pinch has proven to be quite difficult to accomplish. The pinch tends to disrupt due to instabilities, either by the m=0 (sausage) or m=1 (kink) modes. Curtailing the growth of these instabilities has been the primary thrust of z-pinch fusion research, and over the years a wide variety of formation techniques have been tried. The early pinches were driven by relatively slow capacitive discharges and were formed by imploding a plasma column. The advent of fast pulsed power technology brought on a whole new repertoire of formation techniques, including: fast implosions, laser or field-enhanced breakdown in a uniform volume of gas, a discharge inside a small capillary, a frozen deuterium fiber isolated by vacuum, and staged concepts in which one pinch implodes upon another. And although none of these have yet to be successful, some have come tantalizingly close. This paper will review the history of this four-decade long quest for fusion power.

  17. Wire Array Z-Pinch Insights for Enhanced X-Ray Production

    SciTech Connect

    Apruzese, J.P.; Chittenden, J.P.; Greenly, J.B.; Haines, M.G.; Mock, R.C.; Mosher, D.; Peterson, D.L.; Reisman, D.B.; Sanford, T.W.L.; Sinars, D.B.; Spielman, R.B.; Whitnery, K.G.

    1999-01-04

    Comparisons of measured total radiated x-ray power from annular wire-array z-pinches with a variety of models as a function of wire number, array mass, and load radius are reviewed. The data, which are comprehensive, have provided important insights into the features of wire-array dynamics that are critical for high x-ray power generation. Collectively, the comparisons of the data with the model calculations suggest that a number of underlying dynamical mechanisms involving cylindrical asymmetries and plasma instabilities contribute to the measured characteristics. For example, under the general assumption that the measured risetime of the total-radiated-power pulse is related to the thickness of the plasma shell formed on axis, the Heuristic Model [IEEE Trans. Plasma Sci., 26, 1275 (1998)] agrees with the measured risetime under a number of specific assumptions about the way the breakdown of the wires, the wire-plasma expansion, and the Rayleigh-Taylor instability in the r-z plane, interact. Likewise, in the high wire-number regime (where the wires are calculated to form a plasma shell prior to significant radial motion of the shell) the comparisons show that the variation in the power of the radiation generated as a function of load mass and array radius can be simulated by the 2-D Eulerian-radiation-magnetohydrodynamics code (E-RMHC) [Phys. Plasmas 3, 368 (1996)], using a single random-density perturbation that seeds the Rayleigh-Taylor instability in the r-z plane. For a given pulse-power generator, the comparisons suggest that (1) the smallest interwire gaps compatible with practical load construction and (2) the minimum implosion time consistent with the optimum required energy coupling of the generator to the load should produce the highest total-radiated-power levels.

  18. Design of a 5-MA 100-ns linear-transformer-driver accelerator for wire array Z-pinch experiments

    NASA Astrophysics Data System (ADS)

    Zhou, Lin; Li, Zhenghong; Wang, Zhen; Liang, Chuan; Li, Mingjia; Qi, Jianmin; Chu, Yanyun

    2016-03-01

    The linear-transformer-driver (LTD) is a recently developed pulsed-power technology that shows great promise for a number of applications. These include a Z -pinch-driven fission-fusion-hybrid reactor that is being developed by the Chinese Academy of Engineering Physics. In support of the reactor development effort, we are planning to build an LTD-based accelerator that is optimized for driving wire-array Z -pinch loads. The accelerator comprises six modules in parallel, each of which has eight series 0.8-MA LTD cavities in a voltage-adder configuration. Vacuum transmission lines are used from the interior of the adder to the central vacuum chamber where the load is placed. Thus the traditional stack-flashover problem is eliminated. The machine is 3.2 m tall and 12 m in outer diameter including supports. A prototype cavity was built and tested for more than 6000 shots intermittently at a repetition rate of 0.1 Hz. A novel trigger, in which only one input trigger pulse is needed by utilizing an internal trigger brick, was developed and successfully verified in these shots. A full circuit modeling was conducted for the accelerator. The simulation result shows that a current pulse rising to 5.2 MA in 91 ns (10%-90%) can be delivered to the wire-array load, which is 1.5 cm in height, 1.2 cm in initial radius, and 1 mg in mass. The maximum implosion velocity of the load is 32 cm /μ s when compressed to 0.1 of the initial radius. The maximum kinetic energy is 78 kJ, which is 11.7% of the electric energy stored in the capacitors. This accelerator is supposed to enable a radiation energy efficiency of 20%-30%, providing a high efficient facility for research on the fast Z pinch and technologies for repetition-rate-operated accelerators.

  19. Dense Z-pinch (DZP) as a fusion power reactor: preliminary scaling calculations and sysems energy balance

    SciTech Connect

    Hagenson, R.L.; Tai, A.S.; Krakowski, R.A.; Moses, R.W.

    1980-01-01

    A conceptual DT fusion reactor concept is described that is based upon the dense Z-pinch (DZP). This study emphasizes plasma modeling and the parametric assessment of the reactor energy balance. To this end simple analytic and numerical models have been developed and evaluated. The resulting optimal reactor operating point promises a high-Q, low-yield system of a scale that may allow the use of conventional high-voltage Marx/water-line technology to drive a potentially very small reactor system.

  20. Investigating radial wire array Z pinches as a compact x-ray source on the Saturn generator

    DOE PAGES

    Ampleford, David J.; Bland, S. N.; Jennings, Christopher A.; Lebedev, S. V.; Chittenden, J. P.; Cuneo, Michael E.; McBride, Ryan D.; Jones, Brent Manley; Hall, G. N.; Suzuki-Vidal, F.; et al

    2015-08-27

    Radial wire array z pinches, where wires are positioned radially outward from a central cathode to a concentric anode, can act as a compact bright x-ray source that could potentially be used to drive a hohlraum. Experiments were performed on the 7-MA Saturn generator using radial wire arrays. These experiments studied a number of potential risks in scaling radial wire arrays up from the 1-MA level, where they have been shown to be a promising compact X-ray source. Data indicates that at 7 MA, radial wire arrays can radiate ~9 TW with 10-ns full-width at half-maximum from a compact pinch.

  1. Development of novel techniques to study the magnetic field evolution in wire array Z-pinches and X pinches

    NASA Astrophysics Data System (ADS)

    Syed, Wasif

    Understanding the magnetic field topology in wire-array Z-pinches is of great significance for their ultimate application to stockpile stewardship and inertial confinement fusion. We have developed and tested several novel techniques involving material-based sensors to measure magnetic fields as a function of space and time in high energy density plasmas on pulsed power machines. We first briefly introduce a technique that was used to measure a lower limit of the maximum magnetic field of a sub-microsecond duration pulse using magnetic reversal in CoPt thin films. The time-varying magnetic field was generated by an exploding wire array plasma called an X pinch produced on the 0.5 MA, 100 ns pulse duration, XP pulsed power generator. We then introduce a technique based on Faraday rotation that was used to measure magnetic fields in wire-array Z-pinches produced on the 1 MA, 100 ns rise time, COBRA pulsed power generator as well as on the XP generator. This technique measures magnetic fields as a function of space and time using Faraday rotation of a single longitudinal mode (SLM) laser through a magneto-optically active bulk waveguide, multicomponent terbium borate glass, placed adjacent to, or within, the wire array. We have measured fields > 10 T with 100 ns rise times outside of a wire-array Z-pinch for the entire duration (˜250 ns) of the current pulse and as much as ˜2 T inside a wire-array for ˜40 ns from the start of current. This is the first time that such rapidly varying and large fields have been measured using the terbium borate glass. The third method, also based on Faraday rotation of SLM laser light utilized an integrated optical fiber sensor (a fiber-sensor-fiber assembly) on the XP pulsed power generator that also yielded a measurement of the magnetic field of a wire-array Z-pinch for part of the current pulse. Finally, we repeated the third method by fabricating a "thin film waveguide" of terbium borate glass to increase the spatial resolution

  2. Optimal welding parameters for very high power ultrasonic additive manufacturing of smart structures with aluminum 6061 matrix

    NASA Astrophysics Data System (ADS)

    Wolcott, Paul J.; Hehr, Adam; Dapino, Marcelo J.

    2014-03-01

    Ultrasonic additive manufacturing (UAM) is a recent solid state manufacturing process that combines ad- ditive joining of thin metal tapes with subtractive milling operations to generate near net shape metallic parts. Due to the minimal heating during the process, UAM is a proven method of embedding Ni-Ti, Fe-Ga, and PVDF to create active metal matrix composites. Recently, advances in the UAM process utilizing 9 kW very high power (VHP) welding has improved bonding properties, enabling joining of high strength materials previously unweldable with 1 kW low power UAM. Consequently, a design of experiments study was conducted to optimize welding conditions for aluminum 6061 components. This understanding is critical in the design of UAM parts containing smart materials. Build parameters, including weld force, weld speed, amplitude, and temperature were varied based on a Taguchi experimental design matrix and tested for me- chanical strength. Optimal weld parameters were identi ed with statistical methods including a generalized linear model for analysis of variance (ANOVA), mean e ects plots, and interaction e ects plots.

  3. Conversion of electromagnetic energy in Z-pinch process of single planar wire arrays at 1.5 MA

    SciTech Connect

    Liangping, Wang; Mo, Li; Juanjuan, Han; Ning, Guo; Jian, Wu; Aici, Qiu

    2014-06-15

    The electromagnetic energy conversion in the Z-pinch process of single planar wire arrays was studied on Qiangguang generator (1.5 MA, 100 ns). Electrical diagnostics were established to monitor the voltage of the cathode-anode gap and the load current for calculating the electromagnetic energy. Lumped-element circuit model of wire arrays was employed to analyze the electromagnetic energy conversion. Inductance as well as resistance of a wire array during the Z-pinch process was also investigated. Experimental data indicate that the electromagnetic energy is mainly converted to magnetic energy and kinetic energy and ohmic heating energy can be neglected before the final stagnation. The kinetic energy can be responsible for the x-ray radiation before the peak power. After the stagnation, the electromagnetic energy coupled by the load continues increasing and the resistance of the load achieves its maximum of 0.6–1.0 Ω in about 10–20 ns.

  4. X-ray absorption spectroscopy for wire-array Z-pinches at the non-radiative stage

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.; Hakel, P.; Mancini, R. C.; Chittenden, J. P.; Anderson, A.; Shevelko, A. P.; Wiewior, P.; Durmaz, T.; Altemara, S. D.; Papp, D.; Astanovitskiy, A. L.; Nalajala, V.; Chalyy, O.; Dmitriev, O.

    2011-12-01

    Absorption spectroscopy was applied to wire-array Z-pinches on the 1 MA pulsed-power Zebra generator at the Nevada Terawatt Facility (NTF). The 50 TW Leopard laser was coupled with the Zebra generator for X-ray backlighting of wire arrays at the ablation stage. Broadband X-ray emission from a laser-produced Sm plasma was used to backlight Al star wire arrays in the range of 7-9 Å. Two time-integrated X-ray conical spectrometers recorded reference and absorption spectra. The spectrometers were shielded from the bright Z-pinch X-ray burst by collimators. The comparison of plasma-transmitted spectra with reference spectra indicates absorption lines in the range of 8.1-8.4 Å. Analysis of Al K-shell absorption spectra with detailed atomic kinetics models shows a distribution of electron temperature in the range of 10-30 eV that was fitted with an effective two-temperature model. Temperature and density distributions in wire-array plasma were simulated with a three-dimension magneto-hydrodynamic code. Post-processing of this code's output yields synthetic transmission spectrum which is in general agreement with the data.

  5. Deconvolution of Stark broadened spectra for multi-point density measurements in a flow Z-pinch

    SciTech Connect

    Vogman, G. V.; Shumlak, U.

    2011-10-13

    Stark broadened emission spectra, once separated from other broadening effects, provide a convenient non-perturbing means of making plasma density measurements. A deconvolution technique has been developed to measure plasma densities in the ZaP flow Z-pinch experiment. The ZaP experiment uses sheared flow to mitigate MHD instabilities. The pinches exhibit Stark broadened emission spectra, which are captured at 20 locations using a multi-chord spectroscopic system. Spectra that are time- and chord-integrated are well approximated by a Voigt function. The proposed method simultaneously resolves plasma electron density and ion temperature by deconvolving the spectral Voigt profile into constituent functions: a Gaussian function associated with instrument effects and Doppler broadening by temperature; and a Lorentzian function associated with Stark broadening by electron density. The method uses analytic Fourier transforms of the constituent functions to fit the Voigt profile in the Fourier domain. The method is discussed and compared to a basic least-squares fit. The Fourier transform fitting routine requires fewer fitting parameters and shows promise in being less susceptible to instrumental noise and to contamination from neighboring spectral lines. The method is evaluated and tested using simulated lines and is applied to experimental data for the 229.69 nm C III line from multiple chords to determine plasma density and temperature across the diameter of the pinch. As a result, these measurements are used to gain a better understanding of Z-pinch equilibria.

  6. Deconvolution of Stark broadened spectra for multi-point density measurements in a flow Z-pinch

    DOE PAGES

    Vogman, G. V.; Shumlak, U.

    2011-10-13

    Stark broadened emission spectra, once separated from other broadening effects, provide a convenient non-perturbing means of making plasma density measurements. A deconvolution technique has been developed to measure plasma densities in the ZaP flow Z-pinch experiment. The ZaP experiment uses sheared flow to mitigate MHD instabilities. The pinches exhibit Stark broadened emission spectra, which are captured at 20 locations using a multi-chord spectroscopic system. Spectra that are time- and chord-integrated are well approximated by a Voigt function. The proposed method simultaneously resolves plasma electron density and ion temperature by deconvolving the spectral Voigt profile into constituent functions: a Gaussian functionmore » associated with instrument effects and Doppler broadening by temperature; and a Lorentzian function associated with Stark broadening by electron density. The method uses analytic Fourier transforms of the constituent functions to fit the Voigt profile in the Fourier domain. The method is discussed and compared to a basic least-squares fit. The Fourier transform fitting routine requires fewer fitting parameters and shows promise in being less susceptible to instrumental noise and to contamination from neighboring spectral lines. The method is evaluated and tested using simulated lines and is applied to experimental data for the 229.69 nm C III line from multiple chords to determine plasma density and temperature across the diameter of the pinch. As a result, these measurements are used to gain a better understanding of Z-pinch equilibria.« less

  7. Comparison of 1D stagnation solutions to 3D wire-array Z pinch simulations in absence of radiation

    NASA Astrophysics Data System (ADS)

    Yu, Edmund; Velikovich, Alexander; Maron, Yitzhak

    2013-10-01

    In the idealized picture of a Z pinch, a cylindrically symmetric plasma shell implodes towards axis. In this 1D (radial) picture, the resulting stagnation is very efficient: all the kinetic energy of the shell converts to internal energy, as for instance in the Noh shock solution or the homogeneous stagnation flow. If we generalize the problem to 2D by deforming the shell from perfectly circular to oblate, the resulting stagnation will not be as efficient. As in the Hiemenz flow, in which a jet of fluid strikes a rigid flat boundary and squirts out to the sides, the more complicated flows allowed in 2D allow flow kinetic energy to redirect rather than stagnate. With this picture in mind, we might expect the stagnation of a wire-array Z pinch, which in actuality forms a highly distorted 3D imploding plasma, to dissipate its kinetic energy inefficiently due to the lack of symmetry, and be indescribable by means of the idealized 1D stagnation solutions. On the other hand, one might expect that if the imploding plasma is sufficiently messy, the non-uniformities might ``wash out,'' allowing a quasi-1D description of the averaged quantities of plasma. In this work we explore this idea, comparing predictions of 1D stagnation solutions with 3D simulation. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC0 4-94AL85000.

  8. Long implosion time (240 ns) Z-pinch experiments with a large diameter (12 cm) double-shell nozzle

    NASA Astrophysics Data System (ADS)

    Levine, J. S.; Banister, J. W.; Failor, B. H.; Qi, N.; Song, Y.; Sze, H. M.; Fisher, A.

    2004-05-01

    Recently, an 8 cm diameter double-shell nozzle has produced argon Z pinches with high K-shell yields with implosion time of 210 ns. To produce even longer implosion time Z pinches for facilities such as Decade Quad [D. Price, et al., "Electrical and Mechanical Design of the Decade Quad in PRS Mode," in Proceedings of the 12th IEEE Pulsed Power Conference, Monterey, CA, edited by C. Stallings and H. Kirbie (IEEE, New York, 1999), p. 489] (9 MA short circuit current at 300 ns), a larger nozzle (12 cm outer diameter) was designed and fabricated. During initial testing on Double-EAGLE [P. Sincerny et al., Proceedings of the 5th IEEE Pulsed Power Conference, Arlington, VA, edited by M. F. Rose and P. J. Turchi (IEEE, New York, 1985), p. 151], 9 kJ of argon K-shell radiation in a 6 ns full width at half maximum pulse was produced with a 240 ns implosion. The initial gas distributions produced by various nozzle configurations have been measured and their impact on the final radiative characteristics of the pinch are presented. The addition of a central jet to increase the initial gas density near the axis is observed to enhance the pinch quality, increasing K-shell yield by 17% and power by 40% in the best configuration tested.

  9. Magneto-Inertia Confinement Approach (MICA) to fusion in dynamic Z-pinch formed from a frozen deuterium-tritium tube

    NASA Astrophysics Data System (ADS)

    Ikuta, Kazunari

    1987-11-01

    The magneto-inertial confinement approach to fusion in a dynamic z-pinch regime is reconsidered using a new method of generating a hot plasma using a frozen deuterium tube as an initial condition. It will be seen that the technology of fabricating deuterium ice tube is possible if available pulse power technology could induce a current on the order of 10 MA along the tube. The dense z-pinch plasma formed from the electromagnetic implosion of this tubular deuterium-tritium ice with a radius of approximately 1 mm can satisfy the Lawson criterion, provided that its length is 1 cm.

  10. Magneto-Inertia Confinement Approach (MICA) to Fusion in Dynamic Z-Pinch Formed from a Frozen Deuterium-Tritium Tube

    NASA Astrophysics Data System (ADS)

    Ikuta, Kazunari

    1988-02-01

    This paper reconsiders the magneto-inertia confinement approach to fusion in dynamic z-pinch with a new method of generating a hot plasma using a frozen deuterium-tritium (D-T) tube as an initial condition. If modern pulsed power technology can induce the high current of the order of 10 MA along the tube, the dense z-pinch plasma formed from the electro-magnetical implosion of thin tubular D-T ice with a radius of about 1 mm can satisfy the Lawson criterion for its 1 cm length.

  11. A dual-channel, focusing x-ray spectrograph with uniform dispersion for Z pinch plasmas measurement

    SciTech Connect

    Yang Qingguo; Li Zeren; Chen Guanhua; Ye Yan; Huang Xianbin; Cai Hongchun; Li Jing; Xiao Shali

    2012-01-15

    A dual-channel, focusing x-ray spectrograph with uniform dispersion (i.e., the linear dispersion of this spectrograph is a constant) is described for measuring the x-ray spectra emission from the hot, dense Al Z pinch plasmas. The spectrograph uses double uniform-dispersed crystals (e.g., a Quartz 1010 crystal and a Mica 002 crystal) as dispersion elements and a double-film box as detector to achieve the simultaneous recording of the time integrated spectrum covering a wide spectral range of {approx}5-9 A. Since this spectrograph disperse the x-rays on the detector plane with uniform spacing for every wavelength, it needs not the calibration of the wavelength with spatial coordinate, thereby own the advantages of easiness and veracity for spectra identification. The design of this spectrograph and the example of experiment on the ''Yang'' accelerator are presented.

  12. Direct Measurement of the Acceleration of a Probe Beam by a Dense Plasma Focus Z-Pinch

    NASA Astrophysics Data System (ADS)

    Ellsworth, J. L.; Falabella, S.; Rusnak, B.; Schmidt, A. E. W.; Tang, V.

    2013-10-01

    Dense plasma focus (DPF) Z-pinch plasmas produce multiple-MeV ions on a cm-scale length, implying electric field gradients exceeding 100 MV/m in the plasma. We report on the first experiments using a 4 MeV deuteron probe beam to directly measure the electric field gradients produced by the kJ-level DPF experiment at LLNL. This information can be used in conjunction with fully kinetic simulations of DPF plasmas to further our understanding of the mechanisms that produce these beams. An understanding of gradient formation in DPFs is necessary to optimize the gradients in these devices for compact accelerator applications. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.

  13. Investigating plasma viscosity with fast framing photography in the ZaP-HD Flow Z-Pinch experiment

    NASA Astrophysics Data System (ADS)

    Weed, Jonathan Robert

    The ZaP-HD Flow Z-Pinch experiment investigates the stabilizing effect of sheared axial flows while scaling toward a high-energy-density laboratory plasma (HEDLP > 100 GPa). Stabilizing flows may persist until viscous forces dissipate a sheared flow profile. Plasma viscosity is investigated by measuring scale lengths in turbulence intentionally introduced in the plasma flow. A boron nitride turbulence-tripping probe excites small scale length turbulence in the plasma, and fast framing optical cameras are used to study time-evolved turbulent structures and viscous dissipation. A Hadland Imacon 790 fast framing camera is modified for digital image capture, but features insufficient resolution to study turbulent structures. A Shimadzu HPV-X camera captures the evolution of turbulent structures with great spatial and temporal resolution, but is unable to resolve the anticipated Kolmogorov scale in ZaP-HD as predicted by a simplified pinch model.

  14. Physics of Multi-Planar and Compact Cylindrical Wire Arrays Implosions on University-Scale Z-pinch Generators

    SciTech Connect

    Kantsyrev, V. L.; Safronova, A. S.; Esaulov, A. A.; Williamson, K. M.; Shrestha, I.; Ouart, N. D.; Yilmaz, M. F.; Wilcox, P. G.; Osborne, G. C.; Weller, M. E.; Shlyaptseva, V. V.; Chuvatin, A. S.; Rudakov, L. I.; Greenly, J. B.; McBride, R. D.; Knapp, P. F.; Blessener, I. C.; Bell, K. S.; Chalenski, D. A.; Hammer, D. A.

    2009-01-21

    The presented research focuses on investigation of Z-pinch plasma formation, implosion, and radiation characteristics as a function of the load configuration. The single planar and multi-planar wire arrays as well as compact cylindrical wire arrays were studied on the 1.3 MA UNR Zebra and 1 MA Cornell COBRA generators. The largest yields and powers were found for W and Mo double planar and compact wire arrays. A possibility of radiation pulse shaping was demonstrated. Two types of bright spots were observed in plasmas. A comparison of Mo double planar and compact wire array data indicates the possibility that the same heating mechanism operates during the final implosion and stagnation stages.

  15. Table-top water-window soft X-ray microscope using a Z-pinching capillary discharge source

    NASA Astrophysics Data System (ADS)

    Nawaz, M. F.; Nevrkla, M.; Jancarek, A.; Torrisi, A.; Parkman, T.; Turnova, J.; Stolcova, L.; Vrbova, M.; Limpouch, J.; Pina, L.; Wachulak, P.

    2016-07-01

    The development and demonstration of a table-top transmission soft X-ray (SXR) microscope, using a laboratory incoherent capillary discharge source has been carried out. This Z-pinching capillary discharge water-window SXR source, is a first of its kind to be used for high spatial resolution microscopy at λ = 2.88 nm (430 eV) . A grazing incidence ellipsoidal condenser mirror is used for focusing of the SXR radiation at the sample plane. The Fresnel zone plate objective lens is used for imaging of the sample onto a back-illuminated (BI) CCD camera. The achieved half-pitch spatial resolution of the microscope approaches 100 nm, as demonstrated by the knife-edge test. Details about the source, and the construction of the microscope are presented and discussed. Additionally, the SXR images of various samples, proving applicability of such microscope for observation of objects in the nanoscale, are shown.

  16. Self consistent impedance determination in multiple circuit paths for resistive magnetohydrodynamic z-pinch flux compression simulations

    NASA Astrophysics Data System (ADS)

    Peterson, Kyle

    2004-12-01

    Electromagnetic boundary conditions can be troublesome in multi-dimensional magnetohydrodynamic simulations of systems containing complex geometries with multiple circuit paths. Accurate modeling of electromagnetic boundary conditions requires the feedback impedance of conducting plasmas in the computational domain to be modeled self consistently with external circuit boundaries. A new method is presented to dynamically calculate inductive and resistive impedance in multiple circuit paths and determine the electromagnetic boundary conditions in a self consistent manner. The new method was implemented into a two dimensional resistive magnetohydrodynamics code in order to simulate azimuthally opposed magnetic flux compression in a z-pinch configuration. Results of the flux compression simulations demonstrate excellent conservation of energy and circuit stability.

  17. Efficient generation of fast neutrons by magnetized deuterons in an optimized deuterium gas-puff z-pinch

    NASA Astrophysics Data System (ADS)

    Klir, D.; Shishlov, A. V.; Kokshenev, V. A.; Kubes, P.; Labetsky, A. Yu; Rezac, K.; Cherdizov, R. K.; Cikhardt, J.; Cikhardtova, B.; Dudkin, G. N.; Fursov, F. I.; Garapatsky, A. A.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Orcikova, H.; Padalko, V. N.; Ratakhin, N. A.; Sila, O.; Turek, K.; Varlachev, V. A.

    2015-04-01

    Z-pinch experiments with deuterium gas puffs have been carried out on the GIT-12 generator at 3 MA currents. Recently, a novel configuration of a deuterium gas-puff z-pinch was used to accelerate deuterons and to generate fast neutrons. In order to form a homogeneous, uniformly conducting layer at a large initial radius, an inner deuterium gas puff was surrounded by an outer hollow cylindrical plasma shell. The plasma shell consisting of hydrogen and carbon ions was formed at the diameter of 350 mm by 48 plasma guns. A linear mass of the plasma shell was about 5 µg cm-1 whereas a total linear mass of deuterium gas in single or double shell gas puffs was about 100 µg cm-1. The implosion lasted 700 ns and seemed to be stable up to a 5 mm radius. During stagnation, m = 0 instabilities became more pronounced. When a disruption of necks occurred, the plasma impedance reached 0.4 Ω and high energy (>2 MeV) bremsstrahlung radiation together with high energy deuterons were produced. Maximum neutron energies of 33 MeV were observed by axial time-of-flight detectors. The observed neutron spectra could be explained by a suprathermal distribution of deuterons with a high energy tail f≤ft({{E}\\text{d}}\\right)\\propto E\\text{d}-(1.8+/- 0.2) . Neutron yields reached 3.6 × 1012 at a 2.7 MA current. A high neutron production efficiency of 6 × 107 neutrons per one joule of plasma energy resulted from the generation of high energy deuterons and from their magnetization inside plasmas.

  18. Trends in plasma conditions inferred from an analysis of x-ray data from high wire-number, Z-pinch load implosions

    NASA Astrophysics Data System (ADS)

    Whitney, K. G.; Pulsifer, P. E.; Apruzese, J. P.; Thornhill, J. W.; Davis, J.; Chong, Y. K.; Sanford, T. W. L.; Mock, R. C.; Nash, T. J.

    2001-08-01

    An analysis of x-ray data from two series of Z-pinch shots taken on the short current-risetime Saturn accelerator at Sandia National Laboratories [Proceedings of 6th International IEEE Pulsed Power Conference, Arlington, VA, edited by P. J. Turchi and B. H. Bernstein (IEEE, New York, 1987), p. 310] is presented. In one series, the array radius was held constant and the array mass was varied; in the other series, the array mass was held constant and its radius varied. In both sets of experiments, large wire-number loads (N>=93) of aluminum were used in contrast to earlier small wire-number aluminum array experiments on Saturn where N<=42. Average electron temperatures and ion densities were inferred from the data. In addition, from the measured size of the emission region of K-shell x rays and from the inferred ion density, a fraction of the total array mass that participated in the K-shell emission was inferred and found to be directly correlated to the K-shell yields that were measured. This paper also demonstrates that the yields varied as a function of array mass and radius in much closer agreement with predictions [J. Appl. Phys. 67, 1725 (1990)] than had been observed in the earlier small wire-number experiments. Thus, a serious misperception that the reason for the early disagreement was in the calculations and not in the experiments is corrected. These predictions were made using one-dimensional (1D) magnetohydrodynamics calculations. The density and temperature trends inferred from the data analysis are well-behaved and consistent with the 1D calculations. This data analysis confirms the importance of achieving uniform plasma initial conditions and implosion symmetry when comparing computer code calculations with experiment. When the wire number of an array load is increased, a more uniform shell of plasma is calculated initially as the wires explode and, as the plasma stagnates on axis, the x-ray powers and yields are found experimentally to approach the

  19. One- and two-dimensional modeling of argon K-shell emission from gas-puff Z-pinch plasmas

    NASA Astrophysics Data System (ADS)

    Thornhill, J. W.; Chong, Y. K.; Apruzese, J. P.; Davis, J.; Clark, R. W.; Giuliani, J. L.; Terry, R. E.; Velikovich, A. L.; Commisso, R. J.; Whitney, K. G.; Frese, M. H.; Frese, S. D.; Levine, J. S.; Qi, N.; Sze, H.; Failor, B. H.; Banister, J. W.; Coleman, P. L.; Coverdale, C. A.; Jones, B.; Deeney, C.

    2007-06-01

    In this paper, a theoretical model is described and demonstrated that serves as a useful tool for understanding K-shell radiating Z-pinch plasma behavior. Such understanding requires a self-consistent solution to the complete nonlocal thermodynamic equilibrium kinetics and radiation transport in order to realistically model opacity effects and the high-temperature state of the plasma. For this purpose, we have incorporated into the MACH2 two-dimensional magnetohydrodynamic (MHD) code [R. E. Peterkin et al., J. Comput. Phys. 140, 148 (1998)] an equation of state, called the tabular collisional radiative equilibrium (TCRE) model [J. W. Thornhill et al., Phys. Plasmas 8, 3480 (2001)], that provides reasonable approximations to the plasma's opacity state. MACH2 with TCRE is applied toward analyzing the multidimensional implosion behavior that occurred in Decade Quad (DQ) [D. Price et al., Proceedings of the 12th IEEE Pulsed Power Conference, Monterey, CA, edited by C. Stallings and H. Kirbie (IEEE, New York, 1999), p. 489] argon gas puff experiments that employed a 12cm diameter nozzle with and without a central gas jet on axis. Typical peak drive currents and implosion times in these experiments were ˜6MA and ˜230ns. By using Planar Laser Induced Fluorescence measured initial density profiles as input to the calculations, the effect these profiles have on the ability of the pinch to efficiently produce K-shell emission can be analyzed with this combined radiation-MHD model. The calculated results are in agreement with the experimental result that the DQ central-jet configuration is superior to the no-central-jet experiment in terms of producing more K-shell emission. These theoretical results support the contention that the improved operation of the central-jet nozzle is due to the better suppression of instabilities and the higher-density K-shell radiating conditions that the central-jet configuration promotes. When we applied the model toward projecting argon K

  20. Microstructural characterization and mechanical properties of high power ultrasonic spot welded aluminum alloy AA6111–TiAl6V4 dissimilar joints

    SciTech Connect

    Zhang, C.Q. Robson, J.D.; Ciuca, O.; Prangnell, P.B.

    2014-11-15

    Aluminum alloy AA6111 and TiAl6V4 dissimilar alloys were successfully welded by high power ultrasonic spot welding. No visible intermetallic reaction layer was detected in as-welded AA6111/TiAl6V4 welds, even when transmission electron microscopy was used. The effects of welding time and natural aging on peak load and fracture energy were investigated. The peak load and fracture energy of welds increased with an increase in welding time and then reached a plateau. The lap shear strength (peak load) can reach the same level as that of similar Al–Al joints. After natural aging, the fracture mode of welds transferred from ductile fracture of the softened aluminum to interfacial failure due to the strength recovery of AA6111. - Highlights: • Dissimilar Al/Ti welds were produced by high power ultrasonic spot welding. • No visible intermetallic reaction layer was detected on weld interface. • The lap shear strength can reach the same level as that of similar Al–Al joints. • The fracture mode becomes interfacial failure after natural aging.

  1. A kinetic model of the plasma flow at the magnetic z-pinch and the plasmoid structure. Part 2 (in English)

    NASA Astrophysics Data System (ADS)

    Kubes, P.; Prykarpatsky, A. K.; Zagrodzinski, J.; Prykarpatsky, Y. A.

    In this article we will follow the approach developed in articles N.~N.~Bogoliubov, V.~Hr.~Samoilenko, Ukr. Fiz. Zh., 37, 147 (1992); J.~Gibbon, Physica D, 3, 503 (1981) using modern Lie--algebraic and symplectic geometry methods. It is devoted to the description of Boltzman--Vlasov type kinetic equations and some two--dimensional hydrodynamic Benney type flows associated with them. In our case of the cylindrical symmetry taking place at the interrupted magnetic z--pinch in plasma we used intensively the corresponding two--dimensionality of the plasma flow under consideration which made it possible to build a kinetic model of the plasmoid vortex structure with a conserved number of linkages of vortex lines. The latter can be used to explain the observed earlier stability of the plasmoid structure at the magnetic z--pinch.

  2. Simulations of Ar gas-puff Z-pinch radiation sources with double shells and central jets on the Z generator

    DOE PAGES

    Tangri, V.; Harvey-Thompson, Adam James; Giuliani, J. L.; Thornhill, J. W.; Velikovich, A. L.; Apruzese, J. P.; Quart, N. D.; DasGupta, A.; Jones, Brent M.; Jennings, Christopher Ashley

    2016-10-19

    Radiation-magnetohydrodynamic simulations using the non-LTE Mach2-TCRE code in (r,z) geometry are performed for two pairs of recent Ar gas-puff Z-pinch experiments on the refurbished Z generator with an 8 cm diameter nozzle. One pair of shots had an outer-to-inner shell mass ratio of 1:1.6 and a second pair had a ratio of 1:1.

  3. Time- and space-resolved X-ray absorption spectroscopy of aluminum irradiated by a subpicosecond high-power laser

    NASA Astrophysics Data System (ADS)

    Tzortzakis, S.; Audebert, P.; Renaudin, P.; Bastiani-Ceccotti, S.; Geindre, J. P.; Chenais-Popovics, C.; Nagels, V.; Gary, S.; Shepherd, R.; Girard, F.; Matsushima, I.; Peyrusse, O.; Gauthier, J.-C.

    2006-05-01

    The ionization and recombination dynamics of transient aluminum plasmas was measured using point projection K-shell absorption spectroscopy. An aluminum plasma was produced with a subpicosecond beam of the 100-TW laser at the LULI facility and probed at different times with a picosecond X-ray backlighter created with a synchronized subpicosecond laser beam. Fourier-Domain-Interferometry (FDI) was used to measure the electron temperature at the peak of the heating laser pulse. Absorption X-ray spectra at early times are characteristic of a dense and rather homogeneous plasma, with limited longitudinal gradients as shown by hydrodynamic simulations. The shift of the Al K-edge was measured in the cold dense plasma located at the edge of the heated plasma. From the 1s 2p absorption spectra, the average ionization was measured as a function of time and was also modeled with a collisional-radiative atomic physics code coupled with hydrodynamic simulations.

  4. Neutron production in deuterium gas-puff z-pinch with outer plasma shell at current of 3 MA

    NASA Astrophysics Data System (ADS)

    Cikhardt, J.; Klir, D.; Rezac, K.; Cikhardtova, B.; Kravarik, J.; Kubes, P.; Sila, O.; Shishlov, A. V.; Cherdizov, R. K.; Frusov, F. I.; Kokshenev, V. A.; Kurmaev, N. E.; Labetsky, A. Yu.; Ratakhin, N. A.; Dudkin, G. N.; Garapatsky, A. A.; Padalko, V. N.; Varlachev, V. A.; Turek, K.; Krasa, J.

    2015-11-01

    Z-pinch experiments at the current of about 3 MA were carried out on the GIT-12 generator. The outer plasma shell of deuterium gas-puff was generated by the system of 48 plasma guns. This configuration exhibits a high efficiency of the production of DD fusion neutrons with the yield of above 1012 neutrons produced in a single shot with the duration of about 20 ns. The maximum energy of the neutrons produced in this pulse exceeded 30 MeV. The neutron radiation was measured using scintillation TOF detectors, CR-39 nuclear track detectors, bubble detectors BD-PND and BDS-10000 and by several types of nuclear activation detectors. These diagnostic tools were used to measure the anisotropy of neutron fluence and neutron energy spectra. It allows us to estimate the total number of DD neutrons, the contribution of other nuclear reactions, the amount of scattered neutrons, and other parameters of neutron production. This work was supported by the MSMT grants LH13283, LD14089.

  5. Hard X-ray and Particle Beams Research on 1.7 MA Z-pinch and Laser Plasma Experiments

    NASA Astrophysics Data System (ADS)

    Shrestha, Ishor; Kantsyrev, Victor; Safronova, Alla; Esaulov, Andrey; Nishio, Mineyuki; Shlyaptseva, Veronica; Keim, Steven; Weller, Michael; Stafford, Austin; Petkov, Emil; Schultz, Kimberly; Cooper, Matthew; PPDL Team

    2013-10-01

    Studies of hard x-ray (HXR) emission, electron and ion beam generation in z-pinch and laser plasmas are important for Inertial Confinement Fusion (ICF) and development of HXR sources from K-shell and L-shell radiation. The characteristics of HXR and particle beams produced by implosions of planar wire arrays, nested and single cylindrical wire arrays, and X-pinches were analyzed on 100 ns UNR Zebra generator with current up to 1.7 MA. In addition, the comparison of characteristics of HXR and electron beams on Zebra and 350 fs UNR Leopard laser experiments with foils has been performed. The diagnostics include Faraday cups, HXR diodes, different x-ray spectrometers and imaging systems, and ion mass spectrometer using the technique of Thomson parabola. Future work on HXRs and particle beams in HED plasmas is discussed. This work was supported by the DOE/NNSA Cooperative agreement DE-NA0001984 and in part by DE-FC52-06NA27616. This work was also supported by the Defense Threat Reduction Agency, Basic Research Award # HDTRA1-13-1-0033, to University of Nevada, Reno.

  6. Dynamics of a Z Pinch X Ray Source for Heating ICF Relevant Hohlraums to 120-160eV

    SciTech Connect

    SANFORD,THOMAS W. L.; OLSON,RICHARD E.; MOCK,RAYMOND CECIL; CHANDLER,GORDON A.; LEEPER,RAMON J.; NASH,THOMAS J.; RUGGLES,LAURENCE E.; SIMPSON,WALTER W.; STRUVE,KENNETH W.; PETERSON,D.L.; BOWERS,R.L.; MATUSKA,W.

    2000-07-10

    A z-pinch radiation source has been developed that generates 60 {+-} 20 KJ of x-rays with a peak power of 13 {+-} 4 TW through a 4-mm diameter axial aperture on the Z facility. The source has heated NIF (National Ignition Facility)-scale (6-mm diameter by 7-mm high) hohlraums to 122 {+-} 6 eV and reduced-scale (4-mm diameter by 4-mm high) hohlraums to 155 {+-} 8 eV -- providing environments suitable for indirect-drive ICF (Inertial Confinement Fusion) studies. Eulerian-RMHC (radiation-hydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm{sup 3} CH{sub 2} fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by {approximately}40% with only a 3--5% decrease in peak temperature, in agreement with measurements.

  7. Design and optimization of a gas-puff nozzle for staged Z-pinch experiments using computational fluid dynamics simulations

    NASA Astrophysics Data System (ADS)

    Valenzuela, J. C.; Krasheninnikov, I.; Beg, F. N.; Wessel, F.; Rahman, H.; Ney, P.; Presura, R.; McKee, E.; Darling, T.; Covington, A.

    2015-11-01

    Previous experimental work on staged Z-pinches demonstrated that gas liners can efficiently couple energy and implode uniformly a target-plasma. A 1.5 MA, 1 μs current driver was used to implode a magnetized, Kr liner onto a D + target, producing 1010 neutrons per shot and providing clear evidence of enhanced pinch stability. Time-of-flight data suggest that primary and secondary neutrons were produced. MHD simulations show that in Zebra, a 1.5MA and 100ns rise-time current driver, high fusion gain can be attained when the optimum liner and plasma target conditions are used. In this work we present the design and optimization of a liner-on-target nozzle to be fielded in Zebra and demonstrate high fusion gain at 1 MA current level. The nozzle is composed of an annular high atomic number gas-puff and an on-axis plasma gun that will deliver the ionized deuterium target. The nozzle optimization was carried out using the computational fluid dynamics (CFD) code fluent and the MHD code Mach2. The CFD simulation produces density and temperature profiles, as a function of the nozzle shapes and gas conditions, which are then used in Mach2 to find the optimum plasma liner implosion-pinch conditions. Funded by the US Department of Energy, ARPA-E, Control Number 1184-1527.

  8. Measurements of the parameters of a condensed deuterated Z-pinch on the angara-5-1 facility

    NASA Astrophysics Data System (ADS)

    Aleksandrov, V. V.; Bryzgunov, V. A.; Grabovski, E. V.; Gritsuk, A. N.; Volobuev, I. V.; Kazakov, E. D.; Kalinin, Yu. G.; Korolev, V. D.; Laukhin, Ya. I.; Medovshchikov, S. F.; Mitrofanov, K. N.; Oleinik, G. M.; Pimenov, V. G.; Smirnova, E. A.; Ustroev, G. I.; Frolov, I. N.

    2016-04-01

    Results are presented from measurements of the parameters of high-temperature plasma in the Z-pinch neck formed when a current of up to 3.5 MA flows through a low-density polymer load. To enhance the effect of energy concentration, a deuterated microporous polyethylene neck with a mass density of 100 mg/cm3 and diameter of 1-1.3 mm was placed in the central part of the load. During the discharge current pulse, short-lived local hot plasma spots with typical dimensions of about 200-300 μm formed in the neck region. Their formation was accompanied by the generation of soft X-ray pulses with photon energies of E > 0.8 keV and durations of 3-4 ns. The plasma electron temperature in the vicinity of the hot spot was measured from the vacuum UV emission spectra of the iron diagnostic admixture and was found to be about 200-400 eV. The appearance of hot plasma spots was also accompanied by neutron emission with the maximum yield of 3 × 1010 neutrons/shot. The neutron energy spectra were studied by means of the time-of-flight method and were found to be anisotropic with respect to the direction of the discharge current.

  9. Deuterium Gas-Puff Z-pinch as a Source of Fast Ions Producing Intensive Pulse of Neutrons

    NASA Astrophysics Data System (ADS)

    Rezac, K.; Cikhardt, J.; Cikhardtova, B.; Klir, D.; Kravarik, J.; Kubes, P.; Sila, O.; Shishlov, A.; Cherdizov, R.; Fursov, F.; Kokshenev, V.; Kovalchuk, B.; Kurmaev, N.; Labetsky, A.; Ratakhin, N.; Turek, K.

    2015-11-01

    A deuterium gas-puff with outer plasma shell has been examined on GIT-12 generator (on the current level of 3 MA) since 2013. Such a configuration caused more stable implosion at final stage of z-pinch. The consequence of this was a production of intensive pulses of fast ions. During last 4 campaigns in 2013-2015, fast ions were examined by several in-chamber diagnostics such as: stack detector (ion energy), pinhole camera (location of ion source), multi-pinhole camera (asymmetry and anisotropy of ion emission), and ion beam detector (dynamics of ion pulses). A CR-39 track detectors and also GAFCHROMIC HD-V2 films from these diagnostics will be presented. On the basis of obtained results, the solid sample for increasing of neutron yield up to 1e13 could be placed below the cathode mesh. Except of neutron yield, other properties such as: neutron energies (up to 33 MeV), neutron emission time (about 20 ns), and emission anisotropy of neutrons were measured. Such a short and intensive neutron pulse provides various applications. This work was supported by the MSMT project LH13283.

  10. The First Pulsed-Power Z-Pinch Liner-On-Target Hydrodynamics Experiment Diagnosed with Proton Radiography

    NASA Astrophysics Data System (ADS)

    Rousculp, C. L.; Reass, W. A.; Oro, D. M.; Griego, J. R.; Turchi, P. J.; Reinovsky, R. E.; Saunders, A.; Mariam, F. G.; Morris, C.

    2014-10-01

    The first pulse-power driven, dynamic, liner-on-target experiment was successfully conducted at the Los Alamos proton radiography (pRad) facility. 100% data return was achieved on this experiment including a 21-image pRad movie. The experiment was driven with the PHELIX pulsed-power machine that utilizes a high-efficiency (k ~ 0.93) transformer to couple a small capacitor bank (U ~ 300 kJ) to a low inductance condensed-matter experimental load in a Z-pinch configuration. The current pulse (Ipeak = 3.7 MA, δt ~10 μs) was measured via a fiber optic Faraday rotation diagnostic. The experimental load consisted of a cylindrical Al liner (6 cm diam, 3 cm tall, 0.8 mm thick) and a cylindrical Al target (3 cm diam, 3 cm tall, 0.1 mm thick) that was coated with a thin (0.1 mm) uniform layer of tungsten powder (1 micron diam). It is observed that the shock-launched powder layer fully detaches from the target into a spatially correlated, radially converging (vr ~ 800 m/s) ring. The powder distribution is highly modulated in azimuth indicating particle interactions are significant. Results are compared to MHD simulations. Work supported by United States-DOE under Contract DE-AC52-06NA25396.

  11. Burn phase calculations and one-dimensional optimization studies for an inverse z-pinch magnetized target fusion system

    NASA Astrophysics Data System (ADS)

    Subhash, P. V.; Madhavan, S.; Sakthivel, N.; Mishra, V.; Majalee, Aaditya V.; Pahari, P.; Chaturvedi, S.

    2011-08-01

    This paper reports a computational optimization study for an inverse z-pinch magnetized target fusion system (MTF). This has been carried out by varying various parameters such as the magnetizing current, the initial liner radius and thickness, liner length, etc. One-dimensional (1D) magneto-hydrodynamic (MHD) calculations are used for this purpose. Capacitor bank parameters are held constant, as is also the inner conductor radius. The Kadomtsev stability parameter Q0 is kept constant at 0.9 and the maximum plasma β at 0.4. The optimization study has yielded several parametric sets with an energy gain of more than unity, i.e. fusion energy output that exceeds the initial energy in the capacitor bank. A physical explanation for the local optimal points is provided through an energy flow analysis. For one case with energy gain exceeding unity, a simple liner stability analysis has been performed. This involves analytical calculations of the time points at which different liner modes become unstable. For these analytical studies, time-dependent parameters, such as liner acceleration, effective thickness of the liner region that still remains solid, and effective material strength, are obtained from 1D MHD simulations.

  12. Finite Larmor radius magnetohydrodynamic analysis of the Rayleigh-Taylor instability in Z pinches with sheared axial flow

    SciTech Connect

    Qiu, X. M.; Huang, L.; Jian, G. D.

    2007-03-15

    The Rayleigh-Taylor (RT) instability in Z pinches with sheared axial flow (SAF) is analyzed using finite Larmor radius (FLR) magnetohydrodynamic theory, in whose momentum equation the FLR effect (also referred to as the effect of gyroviscosity) is introduced through an anisotropic ion (FLR) stress tensor. A dispersion relation is derived for the linear RT instability. Both analytical and numerical solutions of the dispersion equation are given. The results indicate that the short-wavelength modes of the RT instability can be stabilized by a sufficient FLR, whereas the long-wavelength modes can be stabilized by a sufficient SAF. In the small-wavenumber region, for normalized wavenumber K<2.4, the hybrid RT/KH (Kelvin-Helmholtz) instability is shown to be the most difficult to stabilize. However the synergistic effect of the SAF and gyroviscosity can mitigate both the RT instability in the large-wavenumber region (K>2.4) and the hybrid RT/KH instability in the small-wavenumber region. In addition, this synergistic effect can compress the RT instability to a narrow wavenumber region. Even the thorough stabilization of the RT instability in the large-wavenumber region is possible with a sufficient SAF and a sufficient gyroviscosity.

  13. Design of a 100 J Dense Plasma Focus Z-pinch Device as a Portable Neutron Source

    NASA Astrophysics Data System (ADS)

    Jiang, Sheng; Higginson, Drew; Link, Anthony; Liu, Jason; Schmidt, Andrea

    2015-11-01

    The dense plasma focus (DPF) Z-pinch devices are capable of accelerating ions to high energies through MV/mm-scale electric fields. When deuterium is used as the filling gas, neutrons are generated through beam-target fusion when fast D beams collide with the bulk plasma. The neutron yield on a DPF scales favorably with current, and could be used as portable sources for active interrogation. Past DPF experiments have been optimized empirically. Here we use the particle-in-cell (PIC) code LSP to optimize a portable DPF for high neutron yield prior to building it. In this work, we are designing a DPF device with about 100 J of energy which can generate 106 - 107 neutrons. The simulations are run in the fluid mode for the rundown phase and are switched to kinetic to capture the anomalous resistivity and beam acceleration process during the pinch. A scan of driver parameters, anode geometries and gas pressures are studied to maximize the neutron yield. The optimized design is currently under construction. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (15-ERD-034) at LLNL.

  14. Multicolor, time-gated, soft x-ray pinhole imaging of wire array and gas puff Z pinches on the Z and Saturn pulsed power generators

    NASA Astrophysics Data System (ADS)

    Jones, B.; Coverdale, C. A.; Nielsen, D. S.; Jones, M. C.; Deeney, C.; Serrano, J. D.; Nielsen-Weber, L. B.; Meyer, C. J.; Apruzese, J. P.; Clark, R. W.; Coleman, P. L.

    2008-10-01

    A multicolor, time-gated, soft x-ray pinhole imaging instrument is fielded as part of the core diagnostic set on the 25 MA Z machine [M. E. Savage et al., in Proceedings of the Pulsed Power Plasma Sciences Conference (IEEE, New York, 2007), p. 979] for studying intense wire array and gas puff Z-pinch soft x-ray sources. Pinhole images are reflected from a planar multilayer mirror, passing 277 eV photons with <10 eV bandwidth. An adjacent pinhole camera uses filtration alone to view 1-10 keV photons simultaneously. Overlaying these data provides composite images that contain both spectral as well as spatial information, allowing for the study of radiation production in dense Z-pinch plasmas. Cu wire arrays at 20 MA on Z show the implosion of a colder cloud of material onto a hot dense core where K-shell photons are excited. A 528 eV imaging configuration has been developed on the 8 MA Saturn generator [R. B. Spielman et al., and A. I. P. Conf, Proc. 195, 3 (1989)] for imaging a bright Li-like Ar L-shell line. Ar gas puff Z pinches show an intense K-shell emission from a zippering stagnation front with L-shell emission dominating as the plasma cools.

  15. Multicolor, time-gated, soft x-ray pinhole imaging of wire array and gas puff Z pinches on the Z and Saturn pulsed power generators

    SciTech Connect

    Jones, B.; Coverdale, C. A.; Nielsen, D. S.; Jones, M. C.; Deeney, C.; Serrano, J. D.; Nielsen-Weber, L. B.; Meyer, C. J.; Apruzese, J. P.; Clark, R. W.; Coleman, P. L.

    2008-10-15

    A multicolor, time-gated, soft x-ray pinhole imaging instrument is fielded as part of the core diagnostic set on the 25 MA Z machine [M. E. Savage et al., in Proceedings of the Pulsed Power Plasma Sciences Conference (IEEE, New York, 2007), p. 979] for studying intense wire array and gas puff Z-pinch soft x-ray sources. Pinhole images are reflected from a planar multilayer mirror, passing 277 eV photons with <10 eV bandwidth. An adjacent pinhole camera uses filtration alone to view 1-10 keV photons simultaneously. Overlaying these data provides composite images that contain both spectral as well as spatial information, allowing for the study of radiation production in dense Z-pinch plasmas. Cu wire arrays at 20 MA on Z show the implosion of a colder cloud of material onto a hot dense core where K-shell photons are excited. A 528 eV imaging configuration has been developed on the 8 MA Saturn generator [R. B. Spielman et al., and A. I. P. Conf, Proc. 195, 3 (1989)] for imaging a bright Li-like Ar L-shell line. Ar gas puff Z pinches show an intense K-shell emission from a zippering stagnation front with L-shell emission dominating as the plasma cools.

  16. Multicolor, time-gated, soft x-ray pinhole imaging of wire array and gas puff Z pinches on the Z and Saturn pulsed power generators.

    PubMed

    Jones, B; Coverdale, C A; Nielsen, D S; Jones, M C; Deeney, C; Serrano, J D; Nielsen-Weber, L B; Meyer, C J; Apruzese, J P; Clark, R W; Coleman, P L

    2008-10-01

    A multicolor, time-gated, soft x-ray pinhole imaging instrument is fielded as part of the core diagnostic set on the 25 MA Z machine [M. E. Savage et al., in Proceedings of the Pulsed Power Plasma Sciences Conference (IEEE, New York, 2007), p. 979] for studying intense wire array and gas puff Z-pinch soft x-ray sources. Pinhole images are reflected from a planar multilayer mirror, passing 277 eV photons with <10 eV bandwidth. An adjacent pinhole camera uses filtration alone to view 1-10 keV photons simultaneously. Overlaying these data provides composite images that contain both spectral as well as spatial information, allowing for the study of radiation production in dense Z-pinch plasmas. Cu wire arrays at 20 MA on Z show the implosion of a colder cloud of material onto a hot dense core where K-shell photons are excited. A 528 eV imaging configuration has been developed on the 8 MA Saturn generator [R. B. Spielman et al., and A. I. P. Conf, Proc. 195, 3 (1989)] for imaging a bright Li-like Ar L-shell line. Ar gas puff Z pinches show an intense K-shell emission from a zippering stagnation front with L-shell emission dominating as the plasma cools.

  17. Generation of episodic magnetically driven plasma jets in a radial foil Z-pinch

    SciTech Connect

    Suzuki-Vidal, Francisco; Lebedev, Sergey V.; Bland, Simon N.; Hall, Gareth N.; Swadling, George; Harvey-Thompson, Adam J.; Chittenden, Jeremy P.; Marocchino, Alberto; Ciardi, Andrea; Frank, Adam; Blackman, Eric G.; Bott, Simon C.

    2010-11-15

    We present experimental results of the formation of magnetically driven plasma jets, showing for the first time a way of producing episodic jet/ouflows in the laboratory. The jets are produced using a 6.5 {mu}m thick aluminum disk (a radial foil), which is subjected to the 1 MA, 250 ns current pulse from the MAGPIE generator [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (1996)]. The early time motion of the foil is characterized by the bulk motion of the mass due to the magnetic pressure, together with the formation of a surface plasma following the direction of the JxB force. A low density plasma fills the region above the foil preceding the formation of subsequent magnetically driven jets on the axis of expanding magnetic bubbles. The outflows emerge in timescales of {approx}30-40 ns and their episodic nature is the result of current reconnection in the foil, aided by the formation of current-driven instabilities in the jet and the distribution of mass available from the foil. The additional inductance due to the new current path inside the cavities was measured using an inductive probe, allowing to estimate the energy balance associated with the episodes. The measured temperature of the compressed jet resulted in T{sub e{approx}}300 eV and a magnetic Reynolds number of Re{sub M{approx}}200-1000, allowing the experiments to be in the regime relevant for scaled representations of astrophysical outflows.

  18. What can spectroscopy and imaging of multi-planar wire arrays reveal about Z-pinch radiation physics?

    SciTech Connect

    Osborne, Glenn C.; Esaulov, Andrey A.; Apruzese, John P.; Shrestha, I.; Kantsyrev, Victor Leonidovich; Shlyaptseva, V.; Coverdale, Christine Anne; Rudakov, Leonid I.; Williamson, K. M.; Deeney, Christopher; Ouart, Nicholas D.; Weller, M. E.; Safronova, Alla S.

    2010-07-01

    The planar wire array research on Zebra at UNR that started in 2005 continues experiments with new types of planar loads with results for consideration and comprehensive analysis [see, for example, Kantsyrev et al, HEDP 5, 115 (2009)]. The detailed studies of radiative properties of such loads are important and spectroscopy and imaging constitute a very valuable and informative diagnostic tool. The set of theoretical codes is implemented which provides non-LTE kinetics, wire ablation dynamic, and MHD modeling. This talk is based on the results of new recent experiments with planar wire arrays on Zebra at UNR. We start with results on radiative properties of a uniform single planar wire array (SPWA) from alloyed Al wires and move to combined triple planar wire arrays (TPWA) made from two materials, Cu and Al. Such combined TPWA includes three planar wire rows that are parallel to each other and made of either Cu or Al alloyed wires. Three different configurations (Al/Cu/Al, Cu/Al/Cu, and Cu/Cu/Al) are considered and compared with each other, and with the results from SPWA of the same materials. X-ray time-gated and time integrated pinhole images and spectra are analyzed together with bolometer, PCD, and XRD measurements, and optical images. Emphasis is made on the radiative properties and temporal and spatial evolution of plasma parameters of such two-component plasmas. The opacity effects are considered and the important question of what causes K-shell Al lines to be optically thin in combined TPWAs is addressed. In conclusion, the new findings from studying multi-planar wire array implosions are summarized and their input to Z-pinch radiation physics is discussed.

  19. Numerical and experimental investigations on the interaction of light wire-array Z-pinches with embedded heavy foam converters

    SciTech Connect

    Xiao, Delong; Ding, Ning; Sun, Shunkai; Ye, Fan; Ning, Jiamin; Hu, Qingyuan; Chen, Faxin; Qin, Yi; Xu, Rongkun; Li, Zhenghong

    2014-04-15

    The interaction of a light tungsten wire-array Z-pinch with an embedded heavy foam converter, whose mass ratio is typically less than 0.16, is numerically analyzed and experimentally investigated on the 1.3 MA “QiangGuang I” facility. Computational results show that this implosion process can be divided into three stages: acceleration of the tungsten wire-array plasma, collision, and stagnation. The tungsten plasma is accelerated to a high speed by the J × B force and interacts weakly with the foam plasma in the first stage. Strong energy conversions take place in the second collision stage. When the high speed tungsten plasma impacts on the foam converter, the plasma is thermalized and a radial radiation peak is produced. Meanwhile, a shock wave is generated due to the collision. After the shock rebounds from the axis and meets the W/Foam boundary, the plasma stagnates and the second radial radiation peak appears. The collision and stagnation processes were observed and the two-peak radial radiation pulse was produced in experiments. Increasing the wire-array radius from 4 mm to 6 mm, the kinetic energy of the tungsten plasma is increased, causing a stronger thermalization and generating a higher first radiation peak. Experimental results also showed a higher ratio of the first peak to the second peak in the case of larger wire-array radius. If we add a thin CH film cover onto the surface of the embedded foam converter, the first radiation peak will be hardly changed, because the acceleration of the tungsten plasma is not evidently affected by the film cover. However, the second radiation peak decreases remarkably due to the large load mass and the corresponding weak compression.

  20. Observed Multi-Decade DD and DT Z-Pinch Fusion Rate Scaling in 5 Dense Plasma Focus Fusion Machines

    SciTech Connect

    Hagen, E. C.; Lowe, D. R.; O'Brien, R.; Meehan, B. T.

    2013-06-18

    Dense Plasma Focus (DPF) machines are in use worldwide or a wide variety of applications; one of these is to produce intense, short bursts of fusion via r-Z pinch heating and compression of a working gas. We have designed and constructed a series of these, ranging from portable to a maximum energy storage capacity of 2 MJ. Fusion rates from 5 DPF pulsed fusion generators have been measured in a single laboratory using calibrated activation detectors. Measured rates range from ~ 1015 to more than 1019 fusions per second have been measured. Fusion rates from the intense short (20 – 50 ns) periods of production were inferred from measurement of neutron production using both calibrated activation detectors and scintillator-PMT neutron time of flight (NTOF) detectors. The NTOF detectors are arranged to measure neutrons versus time over flight paths of 30 Meters. Fusion rate scaling versus energy and current will be discussed. Data showing observed fusion cutoff at D-D fusion yield levels of approximately 1*1012, and corresponding tube currents of ~ 3 MA will be shown. Energy asymmetry of product neutrons will also be discussed. Data from the NTOF lines of sight have been used to measure energy asymmetries of the fusion neutrons. From this, center of mass energies for the D(d,n)3He reaction are inferred. A novel re-entrant chamber that allows extremely high single pulse neutron doses (> 109 neutrons/cm2 in 50 ns) to be supplied to samples will be described. Machine characteristics and detector types will be discussed.

  1. Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

    SciTech Connect

    Sandord, T.W.L.; Olson, R.E.; Chandler, G.A.; Hebron, D.E.; Mock, R.C.; Leeper, R.J.; Nash, T.J.; Ruggles, L.E.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.; Bowers, R.L.; Matuska, W.; Peterson, D.L.; Peterson, R.R.

    1999-08-25

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch target on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-{micro}m-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm{sup 3} CH, for example, produces foot-pulse conditions of {minus}85 eV for a duration of {approximately} 10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm{sup 3} CH generates first-step-pulse conditions of {approximately} 122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to {approximately} 150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation (T-(P/A){sup 1/4}). P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation-hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of air or less.

  2. Planar Wire-Array Z-Pinch Implosion Dynamics and X-Ray Scaling at Multiple-MA Drive Currents for a Compact Multisource Hohlraum Configuration

    SciTech Connect

    Jones, B.; Ampleford, D. J.; Vesey, R. A.; Cuneo, M. E.; Coverdale, C. A.; Waisman, E. M.; Jones, M. C.; Fowler, W. E.; Stygar, W. A.; Serrano, J. D.; Vigil, M. P.; Esaulov, A. A.; Kantsyrev, V. L.; Safronova, A. S.; Williamson, K. M.; Chuvatin, A. S.; Rudakov, L. I.

    2010-03-26

    An indirect drive configuration is proposed wherein multiple compact Z-pinch x-ray sources surround a secondary hohlraum. Planar compact wire arrays allow reduced primary hohlraum surface area compared to cylindrical loads. Implosions of planar arrays are studied at up to 15 TW x-ray power on Saturn with radiated yields exceeding the calculated kinetic energy, suggesting other heating paths. X-ray power and yield scaling studied from 1-6 MA motivates viewfactor modeling of four 6-MA planar arrays producing 90 eV radiation temperature in a secondary hohlraum.

  3. Recent Developments in High Energy Density Physics Targets for Experiments at Nif, Omega and the Sandia Z Pinch Facility

    NASA Astrophysics Data System (ADS)

    Nobile, Arthur; Balkey, Matthew; Bartos, Jacob; Batha, Steven; Brooks, Paul; Cameron, Bernard; Cobble, James; Cooley, Jason; Day, Robert; Edwards, John; Elliott, Joyce; Elliott, Norman; Fincke, James; Gomez, Veronica; Hatch, Douglas; Keiter, Paul; Kyrala, George; Lanier, Nicholas; Manzanares, Ruben; Papin, Pallas; Perea, Ron; Pierce, Timothy; Randolph, Blaine; Sandoval, David; Sebring, Robert; Rivera, Gerald; Schmidt, Derek; Snow, Ron; Steckle, Warren; Tierney, Thomas; Valdez, Adelaida; Watt, Robert

    2004-11-01

    Several new targets have recently been developed and fielded to investigate physical phenomena occurring in the high energy density regime. Phenomena studied included interacting hydrodynamic jets, hydrodynamic instabilities in convergent geometry, radiation flow, shock propagation in ignition-relevant materials, and issues associated with double shell targets for achieving ignition on NIF. Targets to study interacting hydrodynamic jets have been fabricated for a NIF campaign. Challenges associated with these targets included producing thin (150 μm) Al disks with 100 and 160 μm precisely placed high quality holes, and fabrication of a thin wall (40 μm) 800 μm diameter cylindrical shock tube filled with low density (90 mg/cm3) carbonized resorcinol formaldehyde foam. Cylindrical targets to investigate hydrodynamic instabilities in convergent geometry as a function of initial surface perturbations have been fabricated. Many experimental campaigns with these targets have been conducted at OMEGA. These targets have been fabricated with a wide range of surface perturbations on an imploding Al marker layer using precision machining methods. The key challenge with these targets was fabrication of a high quality Al marker layer, and placement of specified surface features on the marker layer. Targets to investigate radiation flow and shock propagation in silicon aerogel were developed and fielded at the Sandia Z Pinch facility. The challenging feature associated with these targets was a high quality silicon aerogel disk that is attached to a gold washer containing a hole. Experiments on OMEGA have recently been conducted for the purpose of developing data on radiation absorption and shock propagation through ignition relevant materials. Specifically, we have fabricated targets for these experiments to investigate radiation absorption and shock propagation in Be-Cu alloys. The challenges associated with these targets were fabrication and characterization of very thin Be

  4. Anisotropy of energy losses in high-current Z-pinches produced by the implosion of cylindrical tungsten wire arrays

    NASA Astrophysics Data System (ADS)

    Aleksandrov, V. V.; Volkov, G. S.; Grabovski, E. V.; Gritsuk, A. N.; Lakhtyushko, N. I.; Medovshchikov, S. F.; Oleinik, G. M.; Svetlov, E. V.

    2014-02-01

    Results are presented from measurements of the anisotropy of energy losses in high-current Z-pinches produced by the implosion of wire arrays at the ANGARA-5-1 facility at load currents of up to 4MA. The energy losses were measured in the radial direction and along the pinch axis from the anode side. The main diagnostics were time-integrated thermocouple calorimeters, nanosecond X-ray diodes (XRDs) with different filters, and a foil radiation calorimeter with a time resolution of 2 μs. The azimuthal anisotropy of energy losses was measured for different wire array configurations and different shapes of the high-voltage electrode. The presence of strong initial azimuthal inhomogeneity of the wire mass distribution (sectioned arrays), as well as the use of conical electrodes instead of plane ones, does not increase the azimuthal inhomogeneity of the total energy losses. For cylindrical wire arrays, energy losses in the radial direction are compared with those along the pinch axis. According to XRD and calorimetric measurements, the radiation yield per unit solid angle along the pinch axis is two to three times lower than that in the radial direction. In the axial direction, the energy flux density of the expanding plasma is two to three times lower than the radiation intensity. The measured radiation yield across the pinch is 2.5-5 kJ/sr, while that along the pinch axis is 1-2 kJ/sr. The results obtained by means of XRDs agree to within measurement errors with those obtained using the radiation calorimeter. It is found that the energy per unit solid angle carried by the expanding plasma in the radial direction does not exceed 10% of the soft X-ray yield. Analysis of the structure of time-integrated pinhole images and signals from the radial and axial XRDs shows that radiation emitted in the radial direction from the hot central region of the pinch is partially screened by the less dense surrounding plasma halo, whereas radiation emitted in the axial direction is a

  5. Small-amplitude magnetic Rayleigh-Taylor instability growth in cylindrical liners and Z-pinches imploded in an axial magnetic field

    NASA Astrophysics Data System (ADS)

    Velikovich, A. L.; Giuliani, J. L.; Clark, R. W.; Mikitchuk, D.; Kroupp, E.; Maron, Y.; Fisher, A.; Schmit, P. F.

    2014-10-01

    Recent progress in developing the MagLIF approach to pulsed-power driven inertial confinement fusion has stimulated the interest in observation and mitigation of the magnetic Rayleigh-Taylor instability (MRTI) of liners and Z-pinches imploded in an axial magnetic field. Theoretical analysis of these issues is particularly important because direct numerical simulation of the MRTI development is challenging due to intrinsically 3D helical structure of the fastest-growing modes. We review the analytical small-amplitude theory of the MRTI perturbation development and the weakly nonlinear theory of MRTI mode interaction, emphasizing basic physics, opportunity for 3D code verification against exact analytical solutions, and stabilization criteria. The theory is compared to the experimental results obtained at Weizmann Institute with gas-puff Z pinches and on the Z facility at Sandia with solid liners imploded in an axial magnetic field. Work supported by the US DOE/NNSA, and by the US-Israel Binational Science Foundation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  6. Study of Ablation and Implosion Stages of 1-MA Wire Array Z-Pinch using X-ray Laser-Based Backlighting

    NASA Astrophysics Data System (ADS)

    Anderson, Austin; Ivanov, Vladimir; Papp, Daniel; Talbot, Bjorn; Astanovitskiy, Alexey

    2013-10-01

    The ablation and implosion stages of wire array z-pinches were studied using laser-based x-ray imaging at the 1-MA Zebra pulse power generator at the University of Nevada, Reno. X-ray backlighting at the wavelength of 6.65 Å was provided by hitting a Si target with the 50 TW Leopard laser. Laser-based radiography allows flexibility in both the timing and the position of the x-ray source. The issue of the method is the small energy of the laser pulse compared to radiation of the Z pinch. A spherically bent quartz crystal can give spatial resolution <10 microns and spectral linewidth of the x-ray on the order of 10-4. X-ray imaging allows viewing of the dense core of plasma column during the ablation stage. Wires with diameters 7.6-15 were resolved in test shots. Images of the wire-array at the ablation stage are discussed. Work was supported by the DOE grant DE-SC0008824 and DOE/NNSA UNR grant DE-FC52-06NA27616.

  7. Simulation and mitigation of the magneto-Rayleigh-Taylor instabilities in Z-pinch gas discharge extreme ultraviolet plasma radiation sources

    SciTech Connect

    Huang, B.; Tomizuka, T.; Xie, B.; Sakai, Y.; Zhu, Q.; Song, I.; Okino, A.; Xiao, F.; Watanabe, M.; Hotta, E.

    2013-11-15

    The development and use of a single-fluid two-temperature approximated 2-D Magneto-Hydrodynamics code is reported. Z-pinch dynamics and the evolution of Magneto-Rayleigh-Taylor (MRT) instabilities in a gas jet type Extreme Ultraviolet (EUV) source are investigated with this code. The implosion and stagnation processes of the Z-pinch dynamics and the influence of initial perturbations (single mode, multi- mode, and random seeds) on MRT instability are discussed in detail. In the case of single mode seeds, the simulation shows that the growth rates for mm-scale wavelengths up to 4 mm are between 0.05 and 0.065 ns{sup −1}. For multi-mode seeds, the mode coupling effect leads to a series of other harmonics, and complicates MRT instability evolution. For perturbation by random seeds, the modes evolve to longer wavelengths and finally converge to a mm-scale wavelength approximately 1 mm. MRT instabilities can also alter the pinch stagnation state and lead to temperature and density fluctuations along the Z axis, which eventually affects the homogeneity of the EUV radiation output. Finally, the simulation results are related to experimental results to discuss the mitigations of MRT instability.

  8. Radial evolution of the finite-width plasma sheet in a Z-pinch -- A parametric analysis based on conservation laws

    SciTech Connect

    Sherar, A.G.

    1996-10-01

    An algebraic method to compute the macroscopic radial-averaged quantities (thickness, density, radial velocity) of the plasma sheet in the first compression of simple z-pinches is presented. Following the snowplow model, a set of MHD equations is written in a reference system in which the internal boundary of the plasma sheet is at rest. The magnetic pressure and the energy losses are both modeled as functions of the radius of the sheet, and a time-independent algebraic equation is obtained. Finding the roots of this expression, the thickness of the plasma sheet as a function of its radius can be computed. The temporal evolution of all the quantities of the plasma sheet can also be obtained making an appropriate change to the reference system. Computed values of the temperature of the sheet are in agreement with experimental values. The ranges of validity for the numerical values of the modeling parameters are analyzed.

  9. Development and use of a two-dimensional interferometer to measure mass flow from a multi-shell Z-pinch gas puff.

    PubMed

    Coleman, P L; Lamppa, D C; Madden, R E; Wilson-Elliott, K; Jones, B; Ampleford, D J; Bliss, D E; Jennings, C; Bixler, A; Krishnan, M

    2012-08-01

    For gas puff Z-pinches, the K-shell x-ray yield is maximized with the use of a multi-shell nozzle. Optimization of the yield, verification of hydrodynamic models of the nozzle flows, and plausible MHD code modeling of the implosions require data on the radial and axial (R,Z) distribution of mass in the nozzle's flow field. Interferometry is a well-established technique for acquiring such data. We describe the development and use of a two-dimensional interferometer with emphasis on the required data reduction methods. We also show that the instrument can derive the flow from each individual nozzle in a multi-shell system.

  10. Radial evolution of the finite-width plasma sheet in a z-pinch: A parametric analysis based on conservation laws

    SciTech Connect

    Sherar, A.G.

    1996-12-31

    A simple method that allows to estimate the macroscopic variables (width, temperature, density, radial velocity, etc.) of the plasma sheet in the first compression of a z-pinch, is presented. Following the snow-plow model, the radial compression is assumed as a process in which the mass is swept by a sheet of finite width. Very high pressures can be reached inside the sheet due to magnetic compression, higher than the filling gas pressure. A quasi-equilibrium hypothesis for the pressure of the layer is defined. From this assumption the thickness of the dense plasma sheet can be estimated. A set of MHD equations that include a term to compute total energy losses is used. The system of equations is written in the interface reference system in which the internal boundary of the sheet is at rest. In this early stage of the compression, the plasma temperature is mainly due to heavy particles. The results obtained using this model can explain ionic temperatures measured in cold plasmas which cannot be explained from electron-ion collisions. From an analytical study of the formation solution, a well-defined range of validity for each parameter of the model has been found. Based on physical conditions, these ranges of validity give a criterion to understanding the necessary conditions to build and maintain a moving plasma sheet. Using this model, other geometries besides the cylindrical one can be analyzed in the future.

  11. Soft x-ray (0.2z-pinch plasma radiation sources

    NASA Astrophysics Data System (ADS)

    Failor, B. H.; Qi, N.; Levine, J. S.; Sze, H.; Gullickson, E. M.

    2004-10-01

    Z-pinches can produce intense fluxes of argon K-shell (3 keV) radiation, but typically only a fraction of the load mass near the axis of the pinch radiates in this spectral range. The majority of the mass does not get hot or dense enough to radiate efficiently in the K-shell. We have designed, built, and tested an instrument to image pinch emission, specifically the radial emission profile, at energies below the K-shell in order to track the location of the cooler mass. A gold mirror provides a high-energy cut-off at 2 keV while a transmission grating disperses the incoming radiation and provides a low-energy cutoff at 0.1 keV. A vertical slit images the pinch radiation in the radial direction and the emission profile is recorded with either an extreme ultraviolet-sensitive charge-coupled device camera (time-integrated) or a linear photodiode array (˜1 ns time resolution). We present results for the mirror, grating, and system characterization obtained at the Advanced Light Source synchrotron located at Lawrence Berkeley National Laboratory (Berkeley, CA).

  12. Operational aspects of an externally driven neutron multiplier assembly concept using a Z-pinch 14-MeV Neutron Source (ZEDNA).

    SciTech Connect

    Smith, David Lewis; Heames, Terence John; Parma, Edward J., Jr.; Peters, Curtis D.; Suo-Anttila, Ahti Jorma

    2007-09-01

    This report documents the key safety and operational aspects of a Z-pinch Externally Driven Nuclear Assembly (ZEDNA) reactor concept which is envisioned to be built and operated at the Z-machine facility in Technical Area IV. Operating parameters and reactor neutronic conditions are established that would meet the design requirements of the system. Accident and off-normal conditions are analyzed using a point-kinetics, one-dimensional thermo-mechanical code developed specifically for ZEDNA applications. Downwind dose calculations are presented to determine the potential dose to the collocated worker and public in the event of a hypothetical catastrophic accident. Current and magnetic impulse modeling and the debris shield design are examined for the interface between the Z machine and the ZEDNA. This work was performed as part of the Advanced Fusion Grand Challenge Laboratory Directed Research and Development Program. The conclusion of this work is that the ZEDNA concept is feasible and could be operated at the Z-machine facility without undue risk to collocated workers and the public.

  13. Electrical Resistivity Measurements of Hot Dense Aluminum

    NASA Astrophysics Data System (ADS)

    Benage, J. F.; Shanahan, W. R.; Murillo, M. S.

    1999-10-01

    Electrical transport properties of dense aluminum are measured in the disordered liquidlike phase using a well-tamped, thermally equilibrated, exploding wire z pinch. Direct measurements of the electrical conductivity have been made using voltage and current measurements. Our measurements span the minimum conductivity regime, at higher densities than have been produced previously. We find that some Ziman-like theoretical predictions are in fair agreement with the data and one Ziman-like theoretical approach is in good agreement, in contrast to other experiments performed in similar regimes which indicate poor agreement with such theories.

  14. Specific features of the structure of the Z-pinch emitting region formed during the implosion of a foam-wire load at the ANGARA-5-1 facility

    SciTech Connect

    Mitrofanov, K. N. Grabovski, E. V.; Gritsuk, A. N.; Laukhin, Ya. N.; Aleksandrov, V. V.; Oleinik, G. M.; Medovshchikov, S. F.; Shevel'ko, A. P.

    2013-01-15

    Results are presented from experimental studies of the structure of the compressed plasma of a Z-pinch produced during the implosion of a foam-wire load at the current of up to 3 MA. The foam-wire load consisted of two nested cylindrical cascades, one of which was a solid or hollow cylinder made of low-density agar-agar foam, while the other was a wire array. The wall thickness of a hollow foam cylinder was 100-200 {mu}m. The images of the pinch and its spectrum obtained with the help of multiframe X-ray cameras and a grazing incidence spectrograph with a spatial resolution were analyzed. Data on the spatial structure of the emitting regions and the soft X-ray (SXR) spectrum of the Z-pinch in the final stage of compression of a foam-wire load were obtained. The implosion modes characterized by the formation of hot regions during implosion of such loads were revealed. The characteristic scale lengths of the hot regions were determined. It is shown that the energy distribution of SXR photons in the energy range from 80 eV to 1 keV forms the spatial structure of Z-pinch images recorded during the implosion of foam-wire loads. It is revealed that the spectral density of SXR emission in the photon energy range of 300-600 eV from hot Z-pinch regions exceeds the spectral density of radiation from the neighboring Z-pinch regions by more than one order of magnitude. Groups of lines related to the absorption and emission of radiation by atoms and multicharged ions of carbon and oxygen in the outer foam cascade of a foam-wire load were recorded for the first time by analyzing the spatial distribution of the SXR spectra of multicharged ions of the Z-pinch. The groups of absorption lines of ions (C III, O III, O IV, and O VI) corresponding to absorption of SXR photons in the Z-pinch of a tungsten wire array, which served as the inner cascade of a foam-wire load, were identified. The plasma electron temperature measured from the charge composition of carbon and oxygen ions in

  15. Recyclable transmission line (RTL) and linear transformer driver (LTD) development for Z-pinch inertial fusion energy (Z-IFE) and high yield.

    SciTech Connect

    Sharpe, Robin Arthur; Kingsep, Alexander S. (Kurchatov Institute, Moscow, Russia); Smith, David Lewis; Olson, Craig Lee; Ottinger, Paul F. (Naval Research Laboratory, Washington, DC); Schumer, Joseph Wade (Naval Research Laboratory, Washington, DC); Welch, Dale Robert (Voss Scientific, Albuquerque, NM); Kim, Alexander (High Currents Institute, Tomsk, Russia); Kulcinski, Gerald L. (University of Wisconsin, Madison, WI); Kammer, Daniel C. (University of Wisconsin, Madison, WI); Rose, David Vincent (Voss Scientific, Albuquerque, NM); Nedoseev, Sergei L. (Kurchatov Institute, Moscow, Russia); Pointon, Timothy David; Smirnov, Valentin P.; Turgeon, Matthew C.; Kalinin, Yuri G. (Kurchatov Institute, Moscow, Russia); Bruner, Nichelle "Nicki" (Voss Scientific, Albuquerque, NM); Barkey, Mark E. (University of Alabama, Tuscaloosa, AL); Guthrie, Michael (University of Wisconsin, Madison, WI); Thoma, Carsten (Voss Scientific, Albuquerque, NM); Genoni, Tom C. (Voss Scientific, Albuquerque, NM); Langston, William L.; Fowler, William E.; Mazarakis, Michael Gerrassimos

    2007-01-01

    Z-Pinch Inertial Fusion Energy (Z-IFE) complements and extends the single-shot z-pinch fusion program on Z to a repetitive, high-yield, power plant scenario that can be used for the production of electricity, transmutation of nuclear waste, and hydrogen production, all with no CO{sub 2} production and no long-lived radioactive nuclear waste. The Z-IFE concept uses a Linear Transformer Driver (LTD) accelerator, and a Recyclable Transmission Line (RTL) to connect the LTD driver to a high-yield fusion target inside a thick-liquid-wall power plant chamber. Results of RTL and LTD research are reported here, that include: (1) The key physics issues for RTLs involve the power flow at the high linear current densities that occur near the target (up to 5 MA/cm). These issues include surface heating, melting, ablation, plasma formation, electron flow, magnetic insulation, conductivity changes, magnetic field diffusion changes, possible ion flow, and RTL mass motion. These issues are studied theoretically, computationally (with the ALEGRA and LSP codes), and will work at 5 MA/cm or higher, with anode-cathode gaps as small as 2 mm. (2) An RTL misalignment sensitivity study has been performed using a 3D circuit model. Results show very small load current variations for significant RTL misalignments. (3) The key structural issues for RTLs involve optimizing the RTL strength (varying shape, ribs, etc.) while minimizing the RTL mass. Optimization studies show RTL mass reductions by factors of three or more. (4) Fabrication and pressure testing of Z-PoP (Proof-of-Principle) size RTLs are successfully reported here. (5) Modeling of the effect of initial RTL imperfections on the buckling pressure has been performed. Results show that the curved RTL offers a much greater buckling pressure as well as less sensitivity to imperfections than three other RTL designs. (6) Repetitive operation of a 0.5 MA, 100 kV, 100 ns, LTD cavity with gas purging between shots and automated operation is

  16. Implementation of the thermonuclear process in D3He-9Be plasma on the basis of a Z pinch with an ultrafast laser ignition

    NASA Astrophysics Data System (ADS)

    Voronchev, V. T.; Kukulin, V. I.

    2010-01-01

    A new concept of inertial-magnetic confinement fusion is proposed. This concept is based on a high-current Z pinch combined with a femtosecond laser. The fusion target is composed of a D3He fuel contained under a high pressure inside a sealed cylindrical capsule made from metallic 9Be. An electric discharge along the capsule preheats the target and transforms it into a state of compressed liner. A subsequent TW femtosecond-laser pulse focused on a target end face causes ultrafast cold ignition of a small portion of the D3He fuel. This laser impact generates energetic electrons and ions, which trigger a nuclear-physics mechanism of a catalytic heating of the fuel and also creates a detonation shock wave capable of propagating along the plasma filament. It is shown that the self-sustaining fusion burn wave can appear in the D3He-9Be plasma, in which case the bulk of the energy release is carried by nonradioactive ions, with the energy gain being in excess of 50. The possibility of probing the fusion process by means of gamma-ray spectroscopy is also discussed. The radiative-capture reactions 3He( d, γ), D( d, γ), and 3He(3He, γ) naturally accompanying the burning of the D3He fuel are shown to serve as a convenient diagnostic tool. A nuclear “marker” of D3He fusion on the basis of the detection of monochromatic gamma rays produced in the reaction 9Be( α, γn), which is induced in the liner beryllium shell by energetic fusion alpha particles, is also examined.

  17. Experimental study of star-like and small-diameter wire-array z-pinches on the 1-MA Zebra generator

    SciTech Connect

    Ivanov, V. V.; Sotnikov, V. I.; Kindel, J. M.; Hakel, P.; Mancini, R. C.; Astanovitskiy, A. L.; Haboub, A.; Altemara, S. D.; Le Galloudec, B.; Nalajala, V.; Shevelko, A. P.; Kazakov, E. D.

    2009-01-21

    Star-like wire arrays and small-diameter (1-3 mm in diameter) cylindrical loads were tested in the 1-MA Zebra generator. Mitigation of plasma inhomogeneity was observed in the implosions of star-like loads, which consisted of multiple nested, cylindrical arrays aligned azimuthally such that the wires appear as linear array 'rays' extending from the axis of symmetry. The implosion in these loads is directed along the 'rays' of the star and cascades from wire to wire to the center to form moving plasma columns with smooth leading edges. Despite the low azimuthal symmetry, a star-like wire array produces a stable x-ray pulse with a high peak power and a short duration of 8-12-ns. This can be linked to the stabilization of instabilities due to the multiple nesting. X-ray generation and implosion dynamics in wire arrays 1-16 mm in diameter were investigated to find a transition between the regime with prevailing kinetic energy and 'non-kinetic' plasma heating. Loads 3-8 mm in diameter generate the highest x-ray power at the Zebra generator. The fall of x-ray power in 1-2-mm loads can be linked to the lack of kinetic energy. Laser probing diagnostics show the formation of 'necks' on the pinch during the bubble-like implosion. The energy balance provides the evidence of the enhanced plasma heating in z-pinches. Features of the implosions in small-diameter wire-arrays can help to identify the mechanisms of energy dissipation.

  18. Status On Multi-microsecond Prepulse Technique On Sphinx Machine Going From Nested To Single Wire Array For 800 ns Implosion Time Z-pinch

    NASA Astrophysics Data System (ADS)

    Maury, P.; Calamy, H.; Grunenwald, J.; Lassalle, F.; Zucchini, F.; Loyen, A.; Georges, A.; Morell, A.; Bedoch, J. P.

    2009-01-01

    The Sphinx machine[1] is a 6 MA, 1 μS driver based on the LTD technology, used for Z-pinch experiments. Important improvements of Sphinx radiation output were recently obtained using a multi-microsecond current prepulse[2]. Total power per unit of length is multiplied by a factor of 6 and FWHM divided by a factor of 2.5. Early breakdown of the wires during the prepulse phase dramatically changes the ablation phase leading to an improvement of axial homogeneity of both the implosion and the final radiating column. As a consequence, the cathode bubble observed on classical shots is definitively removed. The implosion is then centered and zippering effect is reduced, leading to simultaneous x-ray emission of the whole length. A great reproducibility is obtained. Nested arrays were used before to mitigate the Rayleigh-Taylor instabilities during the implosion phase. Further experiments with pre-pulse technique are described here were inner array was removed. The goal of these experiments was to see if long prepulse could give stable enough implosion with single array and at the same time increase the η parameter by reducing the mass of the load. Experimental results of single wire array loads of typical dimension 5 cm in height with implosion time between 700 and 900 ns and diameter varying between 80 and 140 mm are given. Parameters of the loads were varying in term of radius and number of wires. Comparisons with nested wire array loads are done and trends are proposed. Characteristics of both the implosion and the final radiating column are shown. 2D MHD numerical simulations of single wire array become easier as there is no interaction between outer and inner array anymore. A systematic study was done using injection mass model to benchmark simulation with experiments.

  19. Viscous Heating of Ions through Saturated Fine-Scale MHD Instabilities in a Z-Pinch at 200-300 KeV Temperature

    NASA Astrophysics Data System (ADS)

    Haines, Malcolm; Coverdale, Christine; Deeney, Chris; Lepell, P. David; Jones, Brent; Apruzese, J. P.

    2006-10-01

    Pulsed power driven Z-pinches yield large X-ray powers at stagnation, the energy of which can exceed by up to factors of 3 or 4, the estimated kinetic energy of the implosion. Furthermore, when electron temperatures are measured at stagnation similar in temperatures would not lead to pressure balance. These problems can be resolved by a theoretical model in which short wavelength (ka >> 1, and viscous Lundquist number ˜ 1), fast growing, m=O MHD instabilities reach a saturated amplitude, and the associated viscous dissipation of the vortices leads to ion heating. Equating this heating rate to the equipartition of energy to electrons leads to an estimate of the ion temperature and pinch radius at pressure balance. Extremely high ion temperatures in the range of 200-300 KeV are predicted from this model for stainless steel wire array experiments on Z at Sandia. These have been confirmed from time-resolved Doppler broadening spectroscopic measurements of the optically thin Fe He-δ line. This conversion of magnetic energy into ion thermal energy occurs on the nanosecond timescale, and can prevent radiative collapse. Any accompanying loss of magnetic flux in this highly conducting plasma can be explained by the occurrence of a large number of hot spots along the axis, with electron density and temperature variating not exactly in phase. This leads to a significant value of the integral of E.dl. Dl along the axis due to the grad Pe term in Ohm's law, analogous to the magnetic field generating term found in laser-plasma interactions. Ref 1. M.G. Haines, et al; Phys. Rev. Lett. 96, 075003 (2006) Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-ACO4-94AL85000.

  20. Status On Multi-microsecond Prepulse Technique On Sphinx Machine Going From Nested To Single Wire Array For 800 ns Implosion Time Z-pinch

    SciTech Connect

    Maury, P.; Calamy, H.; Grunenwald, J.; Lassalle, F.; Zucchini, F.; Loyen, A.; Georges, A.; Morell, A.; Bedoch, J. P.

    2009-01-21

    The Sphinx machine{sup [1]} is a 6 MA, 1 {mu}S driver based on the LTD technology, used for Z-pinch experiments. Important improvements of Sphinx radiation output were recently obtained using a multi-microsecond current prepulse{sup [2]}. Total power per unit of length is multiplied by a factor of 6 and FWHM divided by a factor of 2.5. Early breakdown of the wires during the prepulse phase dramatically changes the ablation phase leading to an improvement of axial homogeneity of both the implosion and the final radiating column. As a consequence, the cathode bubble observed on classical shots is definitively removed. The implosion is then centered and zippering effect is reduced, leading to simultaneous x-ray emission of the whole length. A great reproducibility is obtained. Nested arrays were used before to mitigate the Rayleigh-Taylor instabilities during the implosion phase. Further experiments with pre-pulse technique are described here were inner array was removed. The goal of these experiments was to see if long prepulse could give stable enough implosion with single array and at the same time increase the {eta} parameter by reducing the mass of the load. Experimental results of single wire array loads of typical dimension 5 cm in height with implosion time between 700 and 900 ns and diameter varying between 80 and 140 mm are given. Parameters of the loads were varying in term of radius and number of wires. Comparisons with nested wire array loads are done and trends are proposed. Characteristics of both the implosion and the final radiating column are shown. 2D MHD numerical simulations of single wire array become easier as there is no interaction between outer and inner array anymore. A systematic study was done using injection mass model to benchmark simulation with experiments.

  1. Deposition and thermal characterization of nano-structured aluminum nitride thin film on Cu-W substrate for high power light emitting diode package.

    PubMed

    Cho, Hyun Min; Kim, Min-Sun

    2014-08-01

    In this study, we developed AlN thick film on metal substrate for hybrid type LED package such as chip on board (COB) using metal printed circuit board (PCB). Conventional metal PCB uses ceramic-polymer composite as electrical insulating layer. Thermal conductivities of such type dielectric film are typically in the range of 1~4 W/m · K depending on the ceramic filler. Also, Al or Cu alloy are mainly used for metal base for high thermal conduction to dissipate heat from thermal source mounted on metal PCB. Here we used Cu-W alloy with low thermal expansion coefficient as metal substrate to reduce thermal stress between insulating layer and base metal. AlN with polyimide (PI) powder were used as starting materials for deposition. We could obtain very high thermal conductivity of 28.3 W/m · K from deposited AlN-PI thin film by AlN-3 wt% PI powder. We made hybrid type high power LED package using AlN-PI thin film. We tested thermal performance of this film by thermal transient measurement and compared with conventional metal PCB substrate. PMID:25936009

  2. Deposition and thermal characterization of nano-structured aluminum nitride thin film on Cu-W substrate for high power light emitting diode package.

    PubMed

    Cho, Hyun Min; Kim, Min-Sun

    2014-08-01

    In this study, we developed AlN thick film on metal substrate for hybrid type LED package such as chip on board (COB) using metal printed circuit board (PCB). Conventional metal PCB uses ceramic-polymer composite as electrical insulating layer. Thermal conductivities of such type dielectric film are typically in the range of 1~4 W/m · K depending on the ceramic filler. Also, Al or Cu alloy are mainly used for metal base for high thermal conduction to dissipate heat from thermal source mounted on metal PCB. Here we used Cu-W alloy with low thermal expansion coefficient as metal substrate to reduce thermal stress between insulating layer and base metal. AlN with polyimide (PI) powder were used as starting materials for deposition. We could obtain very high thermal conductivity of 28.3 W/m · K from deposited AlN-PI thin film by AlN-3 wt% PI powder. We made hybrid type high power LED package using AlN-PI thin film. We tested thermal performance of this film by thermal transient measurement and compared with conventional metal PCB substrate.

  3. Using 1D theory to understand 3D stagnation of a wire-array Z pinch in the absence of radiation

    NASA Astrophysics Data System (ADS)

    Yu, Edmund

    2015-11-01

    Many high-energy-density systems implode towards the axis of symmetry, where it collides on itself, forming a hot plasma. However, experiments show these imploding plasmas develop three-dimensional (3D) structures. As a result, the plasma cannot completely dissipate its kinetic energy at stagnation, instead retaining significant 3D flow. A useful tool for understanding the effects of this residual flow is 3D simulation, but the amount and complexity of information can be daunting. To address this problem, we explore the connection between 3D simulation and one-dimensional (1D) theory. Such a connection, if it exists, is mutually beneficial: 1D theory can provide a clear picture of the underlying dynamics of 3D stagnation. On the other hand, deviations between theory and simulation suggest how 1D theory must be modified to account for 3D effects. In this work, we focus on a 3D, magnetohydrodynamic simulation of a compact wire-array Z pinch. To provide a simpler background against which to test our ideas, we artificially turn off radiation during the stagnation phase. Examination of the initial accumulation of mass on axis reveals oblique collision between jets, shock accretion, and vortex formation. Despite evidence for shock-dominated stagnation, a 1D shockless stagnation solution is more appropriate for describing the global dynamics, in that it reproduces the increase of on-axis density with time. However, the 1D solution must be modified to account for 3D effects: the flows suggest enhanced thermal transport as well as centrifugal force. Upon reaching peak compression, the stagnation transitions to a second phase, in which the high-pressure core on axis expands outward into the remaining imploding plasma. During this phase, a 1D shock solution describes the growth of the shock accretion region, as well as the decrease of on-axis density with time. However, the effect of 3D flows is still present: the on-axis temperature does not cool during expansion, which

  4. Plasma evolution and dynamics in high-power vacuum-transmission-line post-hole convolutes

    NASA Astrophysics Data System (ADS)

    Rose, D. V.; Welch, D. R.; Hughes, T. P.; Clark, R. E.; Stygar, W. A.

    2008-06-01

    Vacuum-post-hole convolutes are used in pulsed high-power generators to join several magnetically insulated transmission lines (MITL) in parallel. Such convolutes add the output currents of the MITLs, and deliver the combined current to a single MITL that, in turn, delivers the current to a load. Magnetic insulation of electron flow, established upstream of the convolute region, is lost at the convolute due to symmetry breaking and the formation of magnetic nulls, resulting in some current losses. At very high-power operating levels and long pulse durations, the expansion of electrode plasmas into the MITL of such devices is considered likely. This work examines the evolution and dynamics of cathode plasmas in the double-post-hole convolutes used on the Z accelerator [R. B. Spielman , Phys. Plasmas 5, 2105 (1998)PHPAEN1070-664X10.1063/1.872881]. Three-dimensional particle-in-cell (PIC) simulations that model the entire radial extent of the Z accelerator convolute—from the parallel-plate transmission-line power feeds to the z-pinch load region—are used to determine electron losses in the convolute. The results of the simulations demonstrate that significant current losses (1.5 MA out of a total system current of 18.5 MA), which are comparable to the losses observed experimentally, could be caused by the expansion of cathode plasmas in the convolute regions.

  5. Influence of insulating coating on aluminum wire explosions

    SciTech Connect

    Li, Yang; Wu, Jian; Sheng, Liang; Zhao, Jizhen; Zhang, Mei; Yuan, Yuan; Peng, Bodong; Li, Xingwen

    2014-10-15

    Single wire explosions are widely used in understanding the early stages of z-pinch experiments. This paper presents a serial of experiments conducted on the pulse power generator with ∼1 kA peak current and ∼10 ns rising time in Xi'an Jiao Tong University. Polyimide coated aluminum wires and uncoated ones were tested under three different voltages to analyze the effect of insulating coating. Experimental results showed that insulating coating can increase the energy deposition 10%∼30% in aluminum wires by delaying the voltage collapse and raising the maximum load resistance. The substantial energy deposition resulted in about 20% faster expansion rates for coated wires. Experimental evidence that plasma channel shunts the current from the wire core was observed by streak camera and schlieren graphs. This paper also briefly discussed the influence of nonuniform coating on the morphology of wire expansion.

  6. Influence of insulating coating on aluminum wire explosions

    NASA Astrophysics Data System (ADS)

    Li, Yang; Sheng, Liang; Wu, Jian; Li, Xingwen; Zhao, Jizhen; Zhang, Mei; Yuan, Yuan; Peng, Bodong

    2014-10-01

    Single wire explosions are widely used in understanding the early stages of z-pinch experiments. This paper presents a serial of experiments conducted on the pulse power generator with ˜1 kA peak current and ˜10 ns rising time in Xi'an Jiao Tong University. Polyimide coated aluminum wires and uncoated ones were tested under three different voltages to analyze the effect of insulating coating. Experimental results showed that insulating coating can increase the energy deposition 10%˜30% in aluminum wires by delaying the voltage collapse and raising the maximum load resistance. The substantial energy deposition resulted in about 20% faster expansion rates for coated wires. Experimental evidence that plasma channel shunts the current from the wire core was observed by streak camera and schlieren graphs. This paper also briefly discussed the influence of nonuniform coating on the morphology of wire expansion.

  7. High Power Hall Thrusters

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert; Tverdokhlebov, Sergery; Manzella, David

    1999-01-01

    The development of Hall thrusters with powers ranging from tens of kilowatts to in excess of one hundred kilowatts is considered based on renewed interest in high power. high thrust electric propulsion applications. An approach to develop such thrusters based on previous experience is discussed. It is shown that the previous experimental data taken with thrusters of 10 kW input power and less can be used. Potential mass savings due to the design of high power Hall thrusters are discussed. Both xenon and alternate thruster propellant are considered, as are technological issues that will challenge the design of high power Hall thrusters. Finally, the implications of such a development effort with regard to ground testing and spacecraft intecrati'on issues are discussed.

  8. High-power klystrons

    NASA Astrophysics Data System (ADS)

    Siambis, John G.; True, Richard B.; Symons, R. S.

    1994-05-01

    Novel emerging applications in advanced linear collider accelerators, ionospheric and atmospheric sensing and modification and a wide spectrum of industrial processing applications, have resulted in microwave tube requirements that call for further development of high power klystrons in the range from S-band to X-band. In the present paper we review recent progress in high power klystron development and discuss some of the issues and scaling laws for successful design. We also discuss recent progress in electron guns with potential grading electrodes for high voltage with short and long pulse operation via computer simulations obtained from the code DEMEOS, as well as preliminary experimental results. We present designs for high power beam collectors.

  9. K-shell emission x-ray imaging of z-pinch plasmas with a pinhole and a logarithmic spiral crystal

    SciTech Connect

    Yang Qingguo; Li Zeren; Peng Qixian; Yang Libing; Chen Guanhua; Ye Yan; Huang Xianbin; Cai Hongchun; Li Jing; Xiao Shali

    2011-09-15

    An in-chamber, mini x-ray imaging instrument employs a pinhole and a logarithmic spiral crystal has been developed for obtaining K-shell line images of the imploding aluminum wire array on the ''Yang'' accelerator. The logarithmic spiral crystal acts as a monochromator and a non-dispersive mirror that reflects the pinhole image to a x-ray film detector with a very narrow photon energy bandwidth (<1 eV, mainly determined by the width of rocking curve of the crystal). Two imaging configurations with the use of Quartz (1010) crystal and Mica (002) crystal are designed, respectively, to image the Al Ly{sub {alpha}2} line (1727.7 eV) emission and Al He{sub {alpha}} intercombination line (1588.3 eV) emission. The primary experimental data corresponding to these two configurations are presented and discussed.

  10. High Power Cryogenic Targets

    SciTech Connect

    Gregory Smith

    2011-08-01

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  11. High power density targets

    NASA Astrophysics Data System (ADS)

    Pellemoine, Frederique

    2013-12-01

    In the context of new generation rare isotope beam facilities based on high-power heavy-ion accelerators and in-flight separation of the reaction products, the design of the rare isotope production targets is a major challenge. In order to provide high-purity beams for science, high resolution is required in the rare isotope separation. This demands a small beam spot on the production target which, together with the short range of heavy ions in matter, leads to very high power densities inside the target material. This paper gives an overview of the challenges associated with this high power density, discusses radiation damage issues in targets exposed to heavy ion beams, and presents recent developments to meet some of these challenges through different projects: FAIR, RIBF and FRIB which is the most challenging. Extensive use of Finite Element Analysis (FEA) has been made at all facilities to specify critical target parameters and R&D work at FRIB successfully retired two major risks related to high-power density and heavy-ion induced radiation damage.

  12. High power microwave generator

    DOEpatents

    Ekdahl, C.A.

    1983-12-29

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  13. High power microwave generator

    DOEpatents

    Ekdahl, Carl A.

    1986-01-01

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  14. Collisional-radiative simulations of a supersonic and radiatively cooled aluminum plasma jet

    NASA Astrophysics Data System (ADS)

    Espinosa, G.; Gil, J. M.; Rodriguez, R.; Rubiano, J. G.; Mendoza, M. A.; Martel, P.; Minguez, E.; Suzuki-Vidal, F.; Lebedev, S. V.; Swadling, G. F.; Burdiak, G.; Pickworth, L. A.; Skidmore, J.

    2015-12-01

    A computational investigation based on collisional-radiative simulations of a supersonic and radiatively cooled aluminum plasma jet is presented. The jet, both in vacuum and in argon ambient gas, was produced on the MAGPIE (Mega Ampere Generator for Plasma Implosion Experiments) generator and is formed by ablation of an aluminum foil driven by a 1.4 MA, 250 ns current pulse in a radial foil Z-pinch configuration. In this work, population kinetics and radiative properties simulations of the jet in different theoretical approximations were performed. In particular, local thermodynamic equilibrium (LTE), non-LTE steady state (SS) and non-LTE time dependent (TD) models have been considered. This study allows us to make a convenient microscopic characterization of the aluminum plasma jet.

  15. High power microwave generator

    DOEpatents

    Minich, Roger W.

    1988-01-01

    A device (10) for producing high-powered and coherent microwaves is described. The device comprises an evacuated, cylindrical, and hollow real cathode (20) that is driven to inwardly field emit relativistic electrons. The electrons pass through an internally disposed cylindrical and substantially electron-transparent cylindrical anode (24), proceed toward a cylindrical electron collector electrode (26), and form a cylindrical virtual cathode (32). Microwaves are produced by spatial and temporal oscillations of the cylindrical virtual cathode (32), and by electrons that reflex back and forth between the cylindrical virtual cathode (32) and the cylindrical real cathode (20).

  16. High power coaxial ubitron

    NASA Astrophysics Data System (ADS)

    Balkcum, Adam J.

    In the ubitron, also known as the free electron laser, high power coherent radiation is generated from the interaction of an undulating electron beam with an electromagnetic signal and a static periodic magnetic wiggler field. These devices have experimentally produced high power spanning the microwave to x-ray regimes. Potential applications range from microwave radar to the study of solid state material properties. In this dissertation, the efficient production of high power microwaves (HPM) is investigated for a ubitron employing a coaxial circuit and wiggler. Designs for the particular applications of an advanced high gradient linear accelerator driver and a directed energy source are presented. The coaxial ubitron is inherently suited for the production of HPM. It utilizes an annular electron beam to drive the low loss, RF breakdown resistant TE01 mode of a large coaxial circuit. The device's large cross-sectional area greatly reduces RF wall heat loading and the current density loading at the cathode required to produce the moderate energy (500 keV) but high current (1-10 kA) annular electron beam. Focusing and wiggling of the beam is achieved using coaxial annular periodic permanent magnet (PPM) stacks without a solenoidal guide magnetic field. This wiggler configuration is compact, efficient and can propagate the multi-kiloampere electron beams required for many HPM applications. The coaxial PPM ubitron in a traveling wave amplifier, cavity oscillator and klystron configuration is investigated using linear theory and simulation codes. A condition for the dc electron beam stability in the coaxial wiggler is derived and verified using the 2-1/2 dimensional particle-in-cell code, MAGIC. New linear theories for the cavity start-oscillation current and gain in a klystron are derived. A self-consistent nonlinear theory for the ubitron-TWT and a new nonlinear theory for the ubitron oscillator are presented. These form the basis for simulation codes which, along

  17. HIGH POWER PULSED OSCILLATOR

    DOEpatents

    Singer, S.; Neher, L.K.

    1957-09-24

    A high powered, radio frequency pulse oscillator is described for generating trains of oscillations at the instant an input direct voltage is impressed, or immediately upon application of a light pulse. In one embodiment, the pulse oscillator comprises a photo-multiplier tube with the cathode connected to the first dynode by means of a resistor, and adjacent dynodes are connected to each other through adjustable resistors. The ohmage of the resistors progressively increases from a very low value for resistors adjacent the cathode to a high value adjacent the plate, the last dynode. Oscillation occurs with this circuit when a high negative voltage pulse is applied to the cathode and the photo cathode is bombarded. Another embodiment adds capacitors at the resistor connection points of the above circuit to increase the duration of the oscillator train.

  18. High power arcjet

    NASA Technical Reports Server (NTRS)

    Goelz, T. M.; Auweter-Kurtz, M.; Kurtz, H. L.; Schrade, H. O.

    1992-01-01

    In this period a new mass flow controller was brought into the gas supply system, so that the upper limit for the mass flow rate could be increased up to 500 mg/s with hydrogen. A maximum specific impulse of 1500 s could be achieved with the high powered arcjet (HIPARC) at an efficiency of slightly better than 20 percent. Different nozzle throat diameters had been tested. The 100 kilo-watt input power limit was reached with the 4 mm nozzle throat diameter at a mass flow rate of 400 mg/s. Tests were carried out with different cathode gaps and with three different cathodes. In addition measurements of pressure and gas temperature were taken in the feed line in order to determine the pressure drop in the propellant injectors.

  19. VUV absorption spectroscopy measurements of the role of fast neutral atoms in high-power gap breakdown

    SciTech Connect

    FILUK,A.B.; BAILEY,JAMES E.; CUNEO,MICHAEL E.; LAKE,PATRICK WAYNE; NASH,THOMAS J.; NOACK,DONALD D.; MARON,Y.

    2000-03-20

    The maximum power achieved in a wide variety of high-power devices, including electron and ion diodes, z pinches, and microwave generators, is presently limited by anode-cathode gap breakdown. A frequently-discussed hypothesis for this effect is ionization of fast neutral atoms injected throughout the anode-cathode gap during the power pulse. The authors describe a newly-developed diagnostic tool that provides the first direct test of this hypothesis. Time-resolved vacuum-ultraviolet absorption spectroscopy is used to directly probe fast neutral atoms with 1 mm spatial resolution in the 10 mm anode-cathode gap of the SABRE 5 MV, 1 TW applied-B ion diode. Absorption spectra collected during Ar RF glow discharges and with CO{sub 2} gas fills confirm the reliability of the diagnostic technique. Throughout the 50--100 ns ion diode pulses no measurable neutral absorption is seen, setting upper limits of 0.12--1.5 x 10{sup 14} cm{sup {minus}3} for ground state fast neutral atom densities of H, C, N, O, F. The absence of molecular absorption bands also sets upper limits of 0.16--1.2 x 10{sup 15} cm{sup {minus}3} for common simple molecules. These limits are low enough to rule out ionization throughout the gap as a breakdown mechanism. This technique can now be applied to quantify the role of neutral atoms in other high-power devices.

  20. High Power Density Motors

    NASA Technical Reports Server (NTRS)

    Kascak, Daniel J.

    2004-01-01

    With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it

  1. High power connection system

    DOEpatents

    Schaefer, Christopher E.; Beer, Robert C.; McCall, Mark D.

    2000-01-01

    A high power connection system adapted for automotive environments which provides environmental and EMI shielding includes a female connector, a male connector, and a panel mount. The female connector includes a female connector base and a snap fitted female connector cover. The male connector includes a male connector base and a snap fitted male connector cover. The female connector base has at least one female power terminal cavity for seatably receiving a respective female power terminal. The male connector base has at least one male power terminal cavity for seatably receiving a respective male power terminal. The female connector is covered by a cover seal and a conductive shroud. A pair of lock arms protrude outward from the front end of the male connector base, pass through the panel mount and interface with a lever of a lever rotatably connected to the shroud to thereby mechanically assist mating of the male and female connectors. Safety terminals in the male and female connectors provide a last-to-connect-first-to-break connection with an HVIL circuit.

  2. Microfabricated wire arrays for Z-pinch.

    SciTech Connect

    Spahn, Olga Blum; Rowen, Adam M.; Cich, Michael Joseph; Peake, Gregory Merwin; Arrington, Christian L.; Nash, Thomas J.; Klem, John Frederick; Romero, Dustin Heinz

    2008-10-01

    Microfabrication methods have been applied to the fabrication of wire arrays suitable for use in Z. Self-curling GaAs/AlGaAs supports were fabricated as an initial route to make small wire arrays (4mm diameter). A strain relief structure that could be integrated with the wire was designed to allow displacements of the anode/cathode connections in Z. Electroplated gold wire arrays with integrated anode/cathode bus connections were found to be sufficiently robust to allow direct handling. Platinum and copper plating processes were also investigated. A process to fabricate wire arrays on any substrate with wire thickness up to 35 microns was developed. Methods to handle and mount these arrays were developed. Fabrication of wire arrays of 20mm diameter was demonstrated, and the path to 40mm array fabrication is clear. With some final investment to show array mounting into Z hardware, the entire process to produce a microfabricated wire array will have been demonstrated.

  3. Argon z-pinch implosions on Phoenix

    SciTech Connect

    Fisher, A.; Peterson, G.; Nolting, E.

    1995-12-31

    Upgrades to the Phoenix front end have resulted in a three-fold increase in Argon K-shell x-ray yields. Lack of a transit time isolator between the center conductor and ground necessitated powering the gas-puff hardware with batteries and supplying control via fiber optic cables. A simple gas flow model was developed to optimize the valve/nozzle design. The gas-puff valve and nozzle were modified to produce a 250-{micro}s density rise time. This short rise-time allowed firing on the gas plateau which improved reproducibility. Front end power flow was improved by opening the MITL from 8 to 10-mm and by increasing the dog-leg at the nozzle to obstruct UV light. The highest yield shots were achieved with a 4-cm long load using a 3.5-cm mean diameter nozzle with a mean inward tilt of 13.75 degrees. X-ray pulse widths ranged between 7--15 ns and x-ray pinhole photos suggest uniform assembly on axis. Results and documentation of the Phoenix upgrades are presented.

  4. Silver based batteries for high power applications

    NASA Astrophysics Data System (ADS)

    Karpinski, A. P.; Russell, S. J.; Serenyi, J. R.; Murphy, J. P.

    The present status of silver oxide-zinc technology and applications has been described by Karpinski et al. [A.P. Karpinski, B. Makovetski, S.J. Russell, J.R. Serenyi, D.C. Williams, Silver-Zinc: status of technology and applications, Journal of Power Sources, 80 (1999) 53-60], where the silver-zinc couple is still the preferred choice where high specific energy/energy density, coupled with high specific power/power density are important for high-rate, weight or size/configuration sensitive applications. Perhaps the silver oxide cathode can be considered one of the most versatile electrode materials. When coupled with other anodes and corresponding electrolyte management system, the silver electrode provides for a wide array of electrochemical systems that can be tailored to meet the most demanding, high power requirements. Besides zinc, the most notable include cadmium, iron, metal hydride, and hydrogen electrode for secondary systems, while primary systems include lithium and aluminum. Alloys including silver are also available, such as silver chloride, which when coupled with magnesium or aluminum are primarily used in many seawater applications. The selection and use of these couples is normally the result of a trade-off of many factors. These include performance, safety, risk, reliability, and cost. When high power is required, silver oxide-zinc, silver oxide-aluminum, and silver oxide-lithium are the most energetic. For moderate performance (i.e., lower power), silver oxide-zinc or silver-cadmium would be the system of choice. This paper summarizes the suitability of the silver-based couples, with an emphasis on the silver-zinc system, as primary or rechargeable power sources for high energy/power applications.

  5. Fabrication Processes for Surface-Emitting via External 45-DEGREE Reflectors, High-Power via Arrayed Ridge - Single-Mode Phase-Locked Aluminum Gallium Arsenide/gallium Arsenide Semiconductor Laser Sources.

    NASA Astrophysics Data System (ADS)

    Porkolab, Gyorgy Arpad

    The fabrication of monolithically integrated configurations of semiconductor lasers incorporating multiple functions is still an open issue today in engineering. A useful set of functions to integrate are: surface-emitting, high -power, phase-locked, single-mode, and collimated laser beam output. In this work new materials and advanced fabrication processes are developed for integrating the first four of the five functions listed. The interest in semiconductor lasers is due to their greater than 90% internal quantum efficiency in converting current-flux to photon-flux, their small size and weight, and their wavelength range from 400 to 1,550 nm. Multitudes of applications are possible for semiconductor laser sources ranging from the low-volume market of satellite-based communications systems to the high-volume market of image display screens. Semimetallic amorphous carbon (SMAC) thin film is introduced as an etch mask for chemically assisted ion beam etching (CAIBE) resulting in smooth etched facets in AlGaAs/GaAs at normal- and 45-degrees- incidence angles. A self-aligned etch technique is introduced using 4 separate photoresist selector-masks on top of a fixed SMAC master -mask on top of the AlGaAs/GaAs substrate to perform 4 separate CAIBE etches at 3 different angles and to 3 different depths to create self-aligned 3-dimensional microstructures of 1.3-μm deep ridge waveguides (RWG), 6-μm deep laser facets, and 11- μm long back-to-back 45-degree reflectors arranged in 3 by 100 arrays. Trenches on topside and underside of laser facets are introduced to deflect current away from laser facets. Silicon-rich nitro-oxide thin film is introduced as triple-use encapsulation to provide chemical passivation of AlGaAs/GaAs, optical anti-reflection coating by being refractive-index matched to AlGaAs/GaAs, and electrical insulation. A pincer-action sample-holder for CAIBE is introduced allowing samples to heat up by ion beam heating. Various surface preparations

  6. Single foreplane high power rectenna

    NASA Astrophysics Data System (ADS)

    Alden, A.; Ohno, T.

    1992-05-01

    A dual polarization rectenna capable of high power handling is described. It consists of contiguous dipoles and rectification units on a single substrate. High efficiencies comparable to previous linear and multiplane dual polarization devices have been achieved.

  7. High power ferrite microwave switch

    NASA Technical Reports Server (NTRS)

    Bardash, I.; Roschak, N. K.

    1975-01-01

    A high power ferrite microwave switch was developed along with associated electronic driver circuits for operation in a spaceborne high power microwave transmitter in geostationary orbit. Three units were built and tested in a space environment to demonstrate conformance to the required performance characteristics. Each unit consisted of an input magic-tee hybrid, two non-reciprocal latching ferrite phase shifters, an out short-slot 3 db quadrature coupler, a dual driver electronic circuit, and input logic interface circuitry. The basic mode of operation of the high power ferrite microwave switch is identical to that of a four-port, differential phase shift, switchable circulator. By appropriately designing the phase shifters and electronic driver circuits to operate in the flux-transfer magnetization mode, power and temperature insensitive operation was achieved. A list of the realized characteristics of the developed units is given.

  8. Integrated high power VCSEL systems

    NASA Astrophysics Data System (ADS)

    Moench, Holger; Conrads, Ralf; Gronenborn, Stephan; Gu, Xi; Miller, Michael; Pekarski, Pavel; Pollmann-Retsch, Jens; Pruijmboom, Armand; Weichmann, Ulrich

    2016-03-01

    High power VCSEL systems are a novel laser source used for thermal treatment in industrial manufacturing. These systems will be applied in many applications, which have not used a laser source before. This is enabled by the unique combination of efficiency, compactness and robustness. High power VCSEL system technology encompasses elements far beyond the VCSEL chip itself: i.e. heat sinks, bonding technology and integrated optics. This paper discusses the optimization of these components and processes specifically for building high-power laser systems with VCSEL arrays. New approaches help to eliminate components and process steps and make the system more robust and easier to manufacture. New cooler concepts with integrated electrical and mechanical interfaces have been investigated and offer advantages for high power system design. The bonding process of chips on sub-mounts and coolers has been studied extensively and for a variety of solder materials. High quality of the interfaces as well as good reliability under normal operation and thermal cycling have been realized. A viable alternative to soldering is silver sintering. The very positive results which have been achieved with a variety of technologies indicate the robustness of the VCSEL chips and their suitability for high power systems. Beam shaping micro-optics can be integrated on the VCSEL chip in a wafer scale process by replication of lenses in a polymer layer. The performance of VCSEL arrays with integrated collimation lenses has been positively evaluated and the integrated chips are fully compatible with all further assembly steps. The integrated high power systems make the application even easier and more robust. New examples in laser material processing and pumping of solid state lasers are presented.

  9. High power neutron production targets

    SciTech Connect

    Wender, S.

    1996-06-01

    The author describes issues of concern in the design of targets and associated systems for high power neutron production facilities. The facilities include uses for neutron scattering, accelerator driven transmutation, accelerator production of tritium, short pulse spallation sources, and long pulse spallation sources. Each of these applications requires a source with different design needs and consequently different implementation in practise.

  10. High power microwave simulator development

    NASA Astrophysics Data System (ADS)

    Benford, James

    1987-12-01

    Emerging applications for high power microwaves in defense necessitate the development of reliable GW level sources for simulation of effects. For broadband variable frequency survey work, the vircator (virtual cathode oscillator) was developed; this is a tunable RF source operating from the upper X band to below the L band range. For narrowband fixed frequency studies, a special magnetron was developed.

  11. High power solid state lasers

    SciTech Connect

    Weber, H.

    1988-01-01

    These proceedings discuss the following subjects: trends in materials processing with laser radiation; slabs and high power systems; glasses and new crystals; solid state lasers at HOYA Corp.; lamps, resonators and transmission; glasses as active materials for high average power solid state lasers; flashlamp pumped GGG-crystals; alexandrite lasers; designing telescope resonators; mode operation of neodymium: YAG lasers; intracavity frequency doubling with KTP crystal and thermal effects in cylinder lasers.

  12. High power gas laser amplifier

    DOEpatents

    Leland, Wallace T.; Stratton, Thomas F.

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  13. High power switching and other high power devices

    NASA Astrophysics Data System (ADS)

    Gundersen, Martin

    1992-09-01

    High power thyratrons and devices such as high power microwave sources have cathode-related performance limits. Research is described of a simple, robust 'super-emissive' cathode that produces greater than 10,000 A/sq cm from a macroscopic area (approx. 1 sq cm), and operates with a low pressure (approx. 0.1 torr), spatially uniform glow plasma (density greater than 1015 cu cm). The cathode also can operate as a hollow cathode, and is at the heart of the operation of the pseudospark and back-lighted thyratron. The physics of this hollow and super-emissive cathode is very rich. The hollow cathode geometry traps electrons in the hollow cathode backspace. The lifetime of these electrons enables them to ionize a spatially homogeneous high density glow, and this hollow cathode mode of operation is responsible for certain types of electron and ion beam behavior. A plasma cathode sheath that is formed during this phase leads to super-emissive behavior, which is responsible for high current emission. Super-emissive cathode thyratron-type switches (with higher peak current, voltage, di/dt) being developed for pulsed power switching of lasers, accelerators, high current and high coulomb transfer, Marx bank operation, transfer of technology to commercial applications, high current electron beams, and millimeter wave generation (1 to 100 GHz) are described.

  14. Anode arc motion in high power arcjets

    NASA Technical Reports Server (NTRS)

    Harris, W. J.; O'Hair, E. A.; Hatfield, L. L.; Kristiansen, M.; Mankins, J. S.

    1992-01-01

    The long-term operational lifetime of most medium to high power arcjets is currently limited by the rapid deterioration of the arcjet electrodes. To a large extent, the rate of this deterioration is related to the motion of the arc discharge on the electrode surfaces. This paper details a series of experiments aimed at studying the temporal behavior of dc arcs on a water-cooled radially-segmented 30 kW class arcjet anode. The experimental anode used for these tests was made of copper, and was divided into four equivalent radial segments which were electrically isolated with aluminum oxide gaskets. The current carried by each segment was measured independently using four calibrated resistive shunts, and was analyzed by digital computer. The tests were limited to nitrogen propellant over a current range of 100-250 A dc. Results show that for the range of total currents considered here, the current distribution in the segmented arcjet anode is generally asymmetric, exhibiting random fluctuations over a wide range of frequencies.

  15. Anode arc motion in high power arcjets

    NASA Astrophysics Data System (ADS)

    Harris, W. J.; O'Hair, E. A.; Hatfield, L. L.; Kristiansen, M.; Mankins, J. S.

    1992-07-01

    The long-term operational lifetime of most medium to high power arcjets is currently limited by the rapid deterioration of the arcjet electrodes. To a large extent, the rate of this deterioration is related to the motion of the arc discharge on the electrode surfaces. This paper details a series of experiments aimed at studying the temporal behavior of dc arcs on a water-cooled radially-segmented 30 kW class arcjet anode. The experimental anode used for these tests was made of copper, and was divided into four equivalent radial segments which were electrically isolated with aluminum oxide gaskets. The current carried by each segment was measured independently using four calibrated resistive shunts, and was analyzed by digital computer. The tests were limited to nitrogen propellant over a current range of 100-250 A dc. Results show that for the range of total currents considered here, the current distribution in the segmented arcjet anode is generally asymmetric, exhibiting random fluctuations over a wide range of frequencies.

  16. High-power pulsed lasers

    SciTech Connect

    Holzrichter, J.F.

    1980-04-02

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization.

  17. Optics assembly for high power laser tools

    DOEpatents

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  18. High power ion thruster performance

    NASA Technical Reports Server (NTRS)

    Rawlin, Vincent K.; Patterson, Michael J.

    1987-01-01

    The ion thruster is one of several forms of space electric propulsion being considered for use on future SP-100-based missions. One possible major mission ground rule is the use of a single Space Shuttle launch. Thus, the mass in orbit at the reactor activation altitude would be limited by the Shuttle mass constraints. When the spacecraft subsystem masses are subtracted from this available mass limit, a maximum propellant mass may be calculated. Knowing the characteristics of each type of electric thruster allows maximum values of total impulse, mission velocity increment, and thrusting time to be calculated. Because ion thrusters easily operate at high values of efficiency (60 to 70%) and specific impulse (3000 to 5000 sec), they can impart large values of total impulse to a spacecraft. They also can be operated with separate control of the propellant flow rate and exhaust velocity. This paper presents values of demonstrated and projected performance of high power ion thrusters used in an analysis of electric propulsion for an SP-100 based mission.

  19. Laboratory Astrophysics on High Power Lasers and Pulsed Power Facilities

    SciTech Connect

    Remington, B A

    2002-02-05

    Over the past decade a new genre of laboratory astrophysics has emerged, made possible by the new high energy density (HED) experimental facilities, such as large lasers, z-pinch generators, and high current particle accelerators. (Remington, 1999; 2000; Drake, 1998; Takabe, 2001) On these facilities, macroscopic collections of matter can be created in astrophysically relevant conditions, and its collective properties measured. Examples of processes and issues that can be experimentally addressed include compressible hydrodynamic mixing, strong shock phenomena, radiative shocks, radiation flow, high Mach-number jets, complex opacities, photoionized plasmas, equations of state of highly compressed matter, and relativistic plasmas. These processes are relevant to a wide range of astrophysical phenomena, such as supernovae and supernova remnants, astrophysical jets, radiatively driven molecular clouds, accreting black holes, planetary interiors, and gamma-ray bursts. These phenomena will be discussed in the context of laboratory astrophysics experiments possible on existing and future HED facilities.

  20. High-Power Electromagnetic Thruster Being Developed

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Mikellides, Pavlos G.

    2001-01-01

    High-power electromagnetic thrusters have been proposed as primary in-space propulsion options for several bold new interplanetary and deep-space missions. As the lead center for electric propulsion, the NASA Glenn Research Center designs, develops, and tests high-power electromagnetic technologies to meet these demanding mission requirements. Two high-power thruster concepts currently under investigation by Glenn are the magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT).

  1. Photoconductive switching for high power microwave generation

    SciTech Connect

    Pocha, M.D.; Hofer, W.W.

    1990-10-01

    Photoconductive switching is a technology that is being increasingly applied to generation of high power microwaves. Two primary semiconductors used for these devices are silicon and gallium arsenide. Diamond is a promising future candidate material. This paper discusses the important material parameters and switching modes, critical issues for microwave generation, and future directions for this high power, photoconductive switching technology.

  2. High power laser perforating tools and systems

    SciTech Connect

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-04-22

    ystems devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser perforation of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to perforate such boreholes.

  3. NASA GRC High Power Electromagnetic Thruster Program

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Pensil, Eric J.

    2004-01-01

    High-power electromagnetic thrusters have been proposed as primary in-space propulsion options for several bold new interplanetary and deep-space missions. As the lead center for electric propulsion, the NASA Glenn Research Center designs, develops, and tests high-power electromagnetic technologies to meet these demanding mission requirements. Two high-power thruster concepts currently under investigation by Glenn are the magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). This paper describes the MPD thruster and the test facility.

  4. Aluminum Hydroxide

    MedlinePlus

    Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

  5. Coupling output of multichannel high power microwaves

    SciTech Connect

    Li Guolin; Shu Ting; Yuan Chengwei; Zhang Jun; Yang Jianhua; Jin Zhenxing; Yin Yi; Wu Dapeng; Zhu Jun; Ren Heming; Yang Jie

    2010-12-15

    The coupling output of multichannel high power microwaves is a promising technique for the development of high power microwave technologies, as it can enhance the output capacities of presently studied devices. According to the investigations on the spatial filtering method and waveguide filtering method, the hybrid filtering method is proposed for the coupling output of multichannel high power microwaves. As an example, a specific structure is designed for the coupling output of S/X/X band three-channel high power microwaves and investigated with the hybrid filtering method. In the experiments, a pulse of 4 GW X band beat waves and a pulse of 1.8 GW S band microwave are obtained.

  6. High power, high frequency component test facility

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen; Krawczonek, Walter

    1990-01-01

    The NASA Lewis Research Center has available a high frequency, high power laboratory facility for testing various components of aerospace and/or terrestrial power systems. This facility is described here. All of its capabilities and potential applications are detailed.

  7. High Power Photodetectors for Space Communications Applications

    NASA Technical Reports Server (NTRS)

    Mysoor, Narayan R.

    1995-01-01

    High power photodetectors in coplanar waveguide and distributed traveling-wave structures have been under development for communications applications. The distributed photodetectors demonstrated 70percent efficiency with a linear response up to 25 mW of optical power input.

  8. Coupling output of multichannel high power microwaves

    NASA Astrophysics Data System (ADS)

    Li, Guolin; Shu, Ting; Yuan, Chengwei; Zhang, Jun; Yang, Jianhua; Jin, Zhenxing; Yin, Yi; Wu, Dapeng; Zhu, Jun; Ren, Heming; Yang, Jie

    2010-12-01

    The coupling output of multichannel high power microwaves is a promising technique for the development of high power microwave technologies, as it can enhance the output capacities of presently studied devices. According to the investigations on the spatial filtering method and waveguide filtering method, the hybrid filtering method is proposed for the coupling output of multichannel high power microwaves. As an example, a specific structure is designed for the coupling output of S/X/X band three-channel high power microwaves and investigated with the hybrid filtering method. In the experiments, a pulse of 4 GW X band beat waves and a pulse of 1.8 GW S band microwave are obtained.

  9. High power millimeter wave source development program

    NASA Technical Reports Server (NTRS)

    George, T. V.

    1989-01-01

    High power millimeter wave sources for fusion program; ECH source development program strategy; and 1 MW, 140 GHz gyrotron experiment design philosophy are briefly outlined. This presentation is represented by viewgraphs only.

  10. Optical diagnostics for high power pulsed underwater electrical discharge characterization

    NASA Astrophysics Data System (ADS)

    Deroy, J.; Claverie, A.; Avrillaud, G.; Boustie, M.; Mazanchenko, E.; Assous, D.; Chuvatin, A.

    2014-05-01

    In order to evaluate the behavior of a high power pulsed underwater electrical discharge, and especially characterize the pressure generated by such a discharge, we implemented several optical diagnostics. We first observed directly the expansion of the plasma produced by the dielectric breakdown of the water between the electrodes and the resulting gaseous pulsating bubble. This observation led to an estimate of the pressure inside the bubble with respect to time. We then visualized the propagation of the pressure wave generated by the discharge with shadowgraph and Schlieren setup. The obtained velocity was then used to evaluate the theoretical maximum pressure at the pressure front. Finally, we measured the velocity induced by the pressure wave on a thin aluminum disk with a heterodyne velocimeter and used numerical simulation to obtain a temporal form of pressure. These methods and results can be used to develop and assess performances of processes using underwater electrical discharges to generate pressure waves such as electrohydraulic forming.

  11. Optical Diagnostics For High Power Pulsed Underwater Electrical Discharge Characterization

    NASA Astrophysics Data System (ADS)

    Deroy, Julien; Avrillaud, Gilles; Boustie, Michel; Claverie, Alain; Mazanchenko, Ekaterina; Assous, David; Chuvatin, Alexander

    2013-06-01

    In order to evaluate the behavior of a high power pulsed underwater electrical discharge, and especially characterize the pressure generated by such a discharge, we implemented several optical diagnostics. We first observed directly the expansion of the plasma produced by the dielectric breakdown of the water between the electrodes and the resulting gaseous pulsating bubble. This observation led to an estimate of the pressure inside the bubble with respect to time. We then visualized the propagation of the pressure wave generated by the discharge with shadowgraphy and Schlieren set-up. The obtained velocity was then used to evaluate the theoretical maximum pressure at the pressure front. Finally, we measured the velocity induced by the pressure wave on a thin aluminum disk with a heterodyne velocimeter and used numerical simulation to obtain a temporal form of pressure. These methods and results can be used to develop and assess performances of processes using underwater electrical discharges to generate pressure waves such as electrohydraulic forming.

  12. High power laser apparatus and system

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.; Brandhorst, H. W., Jr. (Inventor)

    1975-01-01

    A high-power, continuous-wave laser was designed for use in power transmission and energy-collecting systems, and for producing incoherent light for pumping a laser material. The laser has a high repetitive pulsing rate per unit time, resulting in a high-power density beam. The laser is composed of xenon flash tubes powered by fast-charging capacitors flashed in succession by a high-speed motor connected to an automobile-type distributor.

  13. Test facilities for high power electric propulsion

    NASA Technical Reports Server (NTRS)

    Sovey, James S.; Vetrone, Robert H.; Grisnik, Stanley P.; Myers, Roger M.; Parkes, James E.

    1991-01-01

    Electric propulsion has applications for orbit raising, maneuvering of large space systems, and interplanetary missions. These missions involve propulsion power levels from tenths to tens of megawatts, depending upon the application. General facility requirements for testing high power electric propulsion at the component and thrust systems level are defined. The characteristics and pumping capabilities of many large vacuum chambers in the United States are reviewed and compared with the requirements for high power electric propulsion testing.

  14. Ablation dynamics in coiled wire-array Z-pinches

    SciTech Connect

    Hall, G. N.; Lebedev, S. V.; Suzuki-Vidal, F.; Swadling, G.; Chittenden, J. P.; Bland, S. N.; Harvey-Thompson, A.; Knapp, P. F.; Blesener, I. C.; McBride, R. D.; Chalenski, D. A.; Blesener, K. S.; Greenly, J. B.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Kusse, B. R.

    2013-02-15

    Experiments to study the ablation dynamics of coiled wire arrays were performed on the MAGPIE generator (1 MA, 240 ns) at Imperial College, and on the COBRA generator at Cornell University's Laboratory of Plasma Studies (1 MA, 100 ns). The MAGPIE generator was used to drive coiled wires in an inverse array configuration to study the distribution of ablated plasma. Using interferometry to study the plasma distribution during the ablation phase, absolute quantitative measurements of electron line density demonstrated very high density contrasts between coiled ablation streams and inter-stream regions many millimetres from the wire. The measured density contrasts for a coiled array were many times greater than that observed for a conventional array with straight wires, indicating that a much greater axial modulation of the ablated plasma may be responsible for the unique implosion dynamics of coiled arrays. Experiments on the COBRA generator were used to study the complex redirection of plasma around a coiled wire that gives rise to the ablation structure exhibited by coiled arrays. Observations of this complex 3D plasma structure were used to validate the current model of coiled array ablation dynamics [Hall et al., Phys. Rev. Lett. 100, 065003 (2008)], demonstrating irrefutably that plasma flow from the wires behaves as predicted. Coiled wires were observed to ablate and implode in the same manner on both machines, indicating that current rise time should not be an issue for the scaling of coiled arrays to larger machines with fast current rise times.

  15. Stable structure in the interrupted z-pinch

    SciTech Connect

    Kubes, P.; Kravarik, J.; Hakr, J.; Kulhanek, P.; Pichal, J. . Faculty of Electrical Engineering)

    1994-10-01

    A low energy (500 J) discharge at relatively high pressure (kPa) between two cone-shaped electrodes has been studied. The discharge geometry enables the formation of two jets with filaments and a compact plasmoid in the center. The existence of the plasmoid was discovered in the experiments. Electron density and temperature were measured by the standard interferometric, schlieren, and spectroscopic methods. A turbulent structure of the jets and plasmoid was proposed for explanation of the measured values and some turbulent parameters were estimated.

  16. Two-dimensional effects in hollow core z-pinches

    NASA Astrophysics Data System (ADS)

    Roderick, N. F.; Hussey, T. W.

    Analytic modeling and magnetohydrodynamic simulations have been conducted to investigate two-dimensional effects in imploding plasma shells. These effects include short wavelength disturbances caused by instabilities at the plasma magnetic field interface, long wavelength instabilities associated with plasma annulus formation, and perturbations resulting from the power flow to the plasma annulus. The numerical calculations were carried out using the two-dimensional single-fluid magnetohydrodynamic (MHD) code MACH2 for different plasma density profiles and electrode geometries. Results for short wavelength perturbations show that these phenomena behave in a manner consistent with analytic linear and heuristic nonlinear models. At stagnation they have a negligible effect on the uniformity during the initial coupling to the target, even for large initial perturbations. The disturbances manifest themselves primarily in a rippling of the back of the plasma shell with significant effects, even in this region, not occurring until late in the stagnation process. Long wavelength perturbations produced by a straight axial gas injection for gas puff implosions can lead to pronounced axial nonuniformity, zippering, at stagnation. Variations of the injection conditions and electrode geometry can produce more uniform stagnation. Changes in the mass profile, gas injection angle, and electrode shape can all be used to achieve significantly greater stagnation uniformity. Consistent calculations for an entire implosion process from a gas injection to stagnation including vacuum power flow indicate the degree of coupling of short wavelength, long wavelength and power flow perturbations. Comparison with experimental data show agreement between analytic, numerical and experimental results.

  17. Axial and Temporal Gradients in Mo Z Pinches

    SciTech Connect

    LePell, P D; Hansen, S B; Shlyaptseva, A S; Coverdale, C; Deeney, C; Apruzese, J P; Fournier, K B; Safronova, U I

    2004-07-14

    Three nested molybdenum wire arrays with initial outer diameters of 45, 50, and 55 mm were imploded by the {approx} 20 MA, 90 ns rise-time current pulse of Sandia's Z accelerator. The implosions generated Mo plasmas with approximately 10% of the array's initial mass reaching Ne-like and nearby ionization stages. These ions emitted 2 - 4 keV L-shell x-rays with radiative powers approaching 10 TW. Mo L-shell spectra with axial and temporal resolution were captured and have been analyzed using a non-LTE collisional-radiative model. We find significant axial variation in the plasma conditions, with electron densities increasing from the cathode ({approx} 3 x 10{sup 20}cm{sup -3}) to near the anode end of the plasma ({approx} 3 x 10{sup 21}cm{sup -3}) and electron temperatures decreasing slightly from the cathode ({approx} 1.7 keV) to the anode end ({approx} 1.5 keV). Time-resolved spectra indicate that the peak electron density is reached before the peak of the L-shell emission and decreases with time, while the electron temperature remains within 10% of 1.7 keV over the 20 - 30 ns L-shell radiation pulse. Finally, while the total yield, peak total power, and peak L-shell power all tended to decrease with increasing initial wire array diameters, the L-shell yield and the average plasma conditions varied little with the initial wire array diameter. Radiative cooling is likely to play an important role in the wire array plasma development.

  18. Thermal design and test of a high power spacecraft transponder platform

    NASA Technical Reports Server (NTRS)

    Stipandic, E. A.; Gray, A. M.; Gedeon, L.

    1975-01-01

    The high power transponder subsystem on board the Communications Technology Satellite (CTS) requires some unique thermal control techniques to maintain the required temperature limits throughout all mission phases. The transponder subsystem includes redundant 20-W output travelling wave tubes and a single 200-W output TWT with highly concentrated thermal dissipations of 70 W and 143 W, respectively. A thermal control system which maintains all components within the required temperature ranges has been designed and verified in thermal balance testing. Included in the design are second surface quartz mirrors on an aluminum honeycomb platform, high thermal conductivity aluminum doubler plates, commandable thermal control heaters and a Variable Conductance Heat Pipe System (VCHPS).

  19. High Power Co-Axial Coupler

    SciTech Connect

    Neubauer, M.; Dudas, A.; Rimmer, Robert A.; Guo, Jiquan; Williams, R. Scott

    2013-12-01

    A very high power Coax RF Coupler (MW-Level) is very desirable for a number of accelerator and commercial applications. For example, the development of such a coupler operating at 1.5 GHz may permit the construction of a higher-luminosity version of the Electron-Ion Collider (EIC) being planned at JLab. Muons, Inc. is currently funded by a DOE STTR grant to develop a 1.5-GHz high-power doublewindowcoax coupler with JLab (about 150 kW). Excellent progress has been made on this R&D project, so we propose an extension of this development to build a very high power coax coupler (MW level peak power and a max duty factor of about 4%). The dimensions of the current coax coupler will be scaled up to provide higher power capability.

  20. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Robert J.; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This viewgraph presentation reports on the development of a high power 780 nm laser suitable for space applications of laser cooling. A possible solution is to use frequency doubling of high power 1560 nm telecom lasers. The presentation shows a diagram of the frequency conversion, and a graph of the second harmonic generation in one crystal, and the use of the cascading crystals. Graphs show the second harmonic power as a function of distance between crystals, second harmonic power vs. pump power, tunability of laser systems.

  1. Continuous high-power gas lasers

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1979-01-01

    High power gas laser concepts are discussed with emphasis on the role that fluid mechanics has played in their development. Consideration is given to three types of systems: gasdynamic lasers, HF supersonic diffusion lasers, and electric discharge lasers. Flow effects and aerodynamic windows in such lasers are briefly described. Future directions of research are outlined.

  2. CHALLENGES FACING HIGH POWER PROTON ACCELERATORS

    SciTech Connect

    Plum, Michael A

    2013-01-01

    This presentation will provide an overview of the challenges of high power proton accelerators such as SNS, J-PARC, etc., and what we have learned from recent experiences. Beam loss mechanisms and methods to mitigate beam loss will also be discussed.

  3. Review of High Power Pulse Transformer Design

    NASA Astrophysics Data System (ADS)

    Zhang, Zhao; Tan, Xiaohua

    Vacuum devices generally work under high power pulse voltage of order 103 V to 106 V, and this pulse voltage could be generated by high power pulse transformer. Relatively, pulse transformer has the advantages of compact structure and excellent repetitiveness. It is expected of short rise-time, wide pulse-width and high energy transferring efficiency in most applications. Aiming at this purpose, it is feasible to select magnetic core with high permeability and high saturation magnetic flux density, use closed core and take some special measures to diminish leakage inductance in the making-process. This paper is a brief summary of high power pulse transformer design. In this paper, the principle, types and characteristics specification of high power pulse transformer are presented, and the design methods of electrical, magnetic and structure parameters are summarized. The methods of shortening rise time, diminishing droop and expanding output pulse-width (electrical parameter design), testing magnetic core materials (magnetic parameter design) and minimizing leakage inductance (structure parameter design) are emphasized.

  4. Targets for high power neutral beams

    SciTech Connect

    Kim, J.

    1980-01-01

    Stopping high-power, long-pulse beams is fast becoming an engineering challenge, particularly in neutral beam injectors for heating magnetically confined plasmas. A brief review of neutral beam target technology is presented along with heat transfer calculations for some selected target designs.

  5. BEAM INSTRUMENTATION FOR HIGH POWER HADRON BEAMS

    SciTech Connect

    Aleksandrov, Alexander V

    2013-01-01

    This presentation will describe developments in the beam diagnostics which support the understanding and operation of high power hadron accelerators. These include the measurement of large dynamic range transverse and longitudinal beam profiles, beam loss detection, and non-interceptive diagnostics.

  6. Industrial Applications of High Power Ultrasonics

    NASA Astrophysics Data System (ADS)

    Patist, Alex; Bates, Darren

    Since the change of the millennium, high-power ultrasound has become an alternative food processing technology applicable to large-scale commercial applications such as emulsification, homogenization, extraction, crystallization, dewatering, low-temperature pasteurization, degassing, defoaming, activation and inactivation of enzymes, particle size reduction, extrusion, and viscosity alteration. This new focus can be attributed to significant improvements in equipment design and efficiency during the late 1990 s. Like most innovative food processing technologies, high-power ultrasonics is not an off-the-shelf technology, and thus requires careful development and scale-up for each and every application. The objective of this chapter is to present examples of ultrasonic applications that have been successful at the commercialization stage, advantages, and limitations, as well as key learnings from scaling up an innovative food technology in general.

  7. Ionospheric Stimulation By High Power Radio Waves

    NASA Astrophysics Data System (ADS)

    Minami, S.; Nishino, M.; Suzuki, Y.; Sato, S.; Tanikawa, T.; Nakamura, Y.; Wong, A. Y.

    1999-01-01

    We have performed an experiment to artificially stimulate the ionosphere using higher power radio waves at the HIPAS (High Power Auroral Stimulation) facility in Alaska. A radio transmission of 2.85 MHz was made at 80 MW (ERP). Diagnostics were made at the other site located 35 km from the transmission site. The results of cross-correlating the excited HF wave and observed with an 8 channel, 30 MHz scanning cosmic radio noise absorption records revealed the excited height of 90 km. Also atmospheric pressure waves observed on the ground show evident propagation of pressure waves which are generated in the ionosphere by the high-power HF wave. The results determine the excitation height of 90 km in the ionosphere and show evidence of the pressure wave coupling between the ionosphere and the lower atmosphere for periods of 10 min

  8. New high power linacs and beam physics

    SciTech Connect

    Wangler, T.P.; Gray, E.R.; Nath, S.; Crandall, K.R.; Hasegawa, K.

    1997-08-01

    New high-power proton linacs must be designed to control beam loss, which can lead to radioactivation of the accelerator. The threat of beam loss is increased significantly by the formation of beam halo. Numerical simulation studies have identified the space-charge interactions, especially those that occur in rms mismatched beams, as a major concern for halo growth. The maximum-amplitude predictions of the simulation codes must be subjected to independent tests to confirm the validity of the results. Consequently, the authors compare predictions from the particle-core halo models with computer simulations to test their understanding of the halo mechanisms that are incorporated in the computer codes. They present and discuss scaling laws that provide guidance for high-power linac design.

  9. High Power Picosecond Laser Pulse Recirculation

    SciTech Connect

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P

    2010-04-12

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  10. Crystal fibers for high power lasers

    NASA Astrophysics Data System (ADS)

    Kim, W.; Florea, C.; Gibson, D.; Peele, J.; Askins, C.; Shaw, B.; Bowman, S.; O'Connor, S.; Bayya, S.; Aggarwal, I.; Sanghera, J. S.

    2013-02-01

    In this paper, we present our recent progress in developing single crystal fibers for high power single frequency fiber lasers. The optical, spectral and morphological properties as well as the loss and gain measured from these crystal fibers drawn by Laser Heated Pedestal Growth (LHPG) system are also discussed. Results on application of various cladding materials on the crystal core and the methods of fiber end-face polishing are also presented.

  11. High-power picosecond laser pulse recirculation.

    PubMed

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P J

    2010-07-01

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high-power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering-based light sources. We demonstrate up to 40x average power enhancement of frequency-doubled submillijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  12. High-power picosecond laser pulse recirculation.

    PubMed

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P J

    2010-07-01

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high-power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering-based light sources. We demonstrate up to 40x average power enhancement of frequency-doubled submillijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses. PMID:20596201

  13. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  14. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  15. High Power MPD Thruster Performance Measurements

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Strzempkowski, Eugene; Pencil, Eric

    2004-01-01

    High power magnetoplasmadynamic (MPD) thrusters are being developed as cost effective propulsion systems for cargo transport to lunar and Mars bases, crewed missions to Mars and the outer planets, and robotic deep space exploration missions. Electromagnetic MPD thrusters have demonstrated, at the laboratory level, the ability to process megawatts of electrical power while providing significantly higher thrust densities than electrostatic electric propulsion systems. The ability to generate higher thrust densities permits a reduction in the number of thrusters required to perform a given mission, and alleviates the system complexity associated with multiple thruster arrays. The specific impulse of an MPD thruster can be optimized to meet given mission requirements, from a few thousand seconds with heavier gas propellants up to 10,000 seconds with hydrogen propellant. In support of programs envisioned by the NASA Office of Exploration Systems, Glenn Research Center is developing and testing quasi-steady MW-class MPD thrusters as a prelude to steady state high power thruster tests. This paper provides an overview of the GRC high power pulsed thruster test facility, and presents preliminary performance data for a quasi-steady baseline MPD thruster geometry.

  16. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  17. High Power UV LED Industrial Curing Systems

    SciTech Connect

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  18. Beam Stop For High-Power Lasers

    NASA Technical Reports Server (NTRS)

    Mcdermid, Iain S.; Williamson, William B.

    1990-01-01

    Graphite/aluminum plate absorbs most of light. Beam stop fits on standard optical mounting fixture. Graphite plate thick enough to absorb incident laser beam but thin enough to transfer heat quickly to heat sink. Device used for variety of blocking purposes. For example, blocks laser beam after it passes through experimental setup, or at each stage of setup so stages checked and tested in sequence. Negligible reflectance of device is valuable safety feature, protecting both users and equipment from reflections.

  19. Aluminum Analysis.

    ERIC Educational Resources Information Center

    Sumrall, William J.

    1998-01-01

    Presents three problems based on the price of aluminum designed to encourage students to be cooperative and to use an investigative approach to learning. Students collect and synthesize information, analyze results, and draw conclusions. (AIM)

  20. Hardening and welding with high-power diode lasers

    NASA Astrophysics Data System (ADS)

    Ehlers, Bodo; Herfurth, Hans-Joachim; Heinemann, Stefan

    2000-03-01

    Commercially available high power diode lasers (HPDLs) with output powers of up to 6 kW have been recognized as an interesting tool for industrial applications. In certain fields of application they offer many advantages over Nd:YAG and CO2 lasers because of their low maintenance, compact design and low capital costs. Examples of successful industrial implementation of HPDLs include plastic welding, surface hardening and heat conduction welding of stainless steel and aluminum. The joining of plastics with an HPDL offers the advantages of producing a weld seam with high strength, high consistency and superior appearance. One example is the keyless entry system introduced with the Mercedes E-class where the microelectronic circuits are embedded in a plastic housing. Other applications include instrument panels, cell phones, headlights and tail lights. Applications in the field of surface treatment of metals profit from the HPDL's inherent line-shaped focus and the homogeneous intensity distribution across this focus. An HPDL system is used within the industry to harden rails for coordinate measurement machines. This system contains a customized zoom optic to focus the laser light onto the rails. With the addition of a temperature control, even complex shapes can be hardened with a constant depth and minimum distortion.

  1. High-power LEDs for plant cultivation

    NASA Astrophysics Data System (ADS)

    Tamulaitis, Gintautas; Duchovskis, Pavelas; Bliznikas, Zenius; Breive, Kestutis; Ulinskaite, Raimonda; Brazaityte, Ausra; Novickovas, Algirdas; Zukauskas, Arturas; Shur, Michael S.

    2004-10-01

    We report on high-power solid-state lighting facility for cultivation of greenhouse vegetables and on the results of the study of control of photosynthetic activity and growth morphology of radish and lettuce imposed by variation of the spectral composition of illumination. Experimental lighting modules (useful area of 0.22 m2) were designed based on 4 types of high-power light-emitting diodes (LEDs) with emission peaked in red at the wavelengths of 660 nm and 640 nm (predominantly absorbed by chlorophyll a and b for photosynthesis, respectively), in blue at 455 nm (phototropic function), and in far-red at 735 nm (important for photomorphology). Morphological characteristics, chlorophyll and phytohormone concentrations in radish and lettuce grown in phytotron chambers under lighting with different spectral composition of the LED-based illuminator and under illumination by high pressure sodium lamps with an equivalent photosynthetic photon flux density were compared. A well-balanced solid-state lighting was found to enhance production of green mass and to ensure healthy morphogenesis of plants compared to those grown using conventional lighting. We observed that the plant morphology and concentrations of morphologically active phytohormones is strongly affected by the spectral composition of light in the red region. Commercial application of the LED-based illumination for large-scale plant cultivation is discussed. This technology is favorable from the point of view of energy consumption, controllable growth, and food safety but is hindered by high cost of the LEDs. Large scale manufacturing of high-power red AlInGaP-based LEDs emitting at 650 nm and a further decrease of the photon price for the LEDs emitting in the vicinity of the absorption peak of chlorophylls have to be achieved to promote horticulture applications.

  2. Scaling blackbody laser to high powers

    NASA Technical Reports Server (NTRS)

    Deyoung, R. J.

    1985-01-01

    Lasers pumped by solar heated blackbody cavities have potential for multimegawatt power beaming in space. There are two basic types of blackbody lasers; cavity pumped and transfer system. The transfer system is judged to be more readily scalable to high power. In this system, either N2 or CO is heated by the blackbody cavity then transferred into the laser cavity where CO2 is injected. The N2-CO2 system was demonstrated, but probably has lower efficiency than the CO-CO system. The characteristics of potential transfer laser systems are outlined.

  3. High power, high frequency, vacuum flange

    DOEpatents

    Felker, B.; McDaniel, M.R.

    1993-03-23

    An improved waveguide flange is disclosed for high power operation that helps prevent arcs from being initiated at the junctions between waveguide sections. The flanges at the end of the waveguide sections have counter bores surrounding the waveguide tubes. When the sections are bolted together the counter bores form a groove that holds a fully annealed copper gasket. Each counterbore has a beveled step that is specially configured to insure the gasket forms a metal-to-metal vacuum seal without gaps or sharp edges. The resultant inner surface of the waveguide is smooth across the junctions between waveguide sections, and arcing is prevented.

  4. High power, high frequency, vacuum flange

    DOEpatents

    Felker, Brian; McDaniel, Michael R.

    1993-01-01

    An improved waveguide flange is disclosed for high power operation that helps prevent arcs from being initiated at the junctions between waveguide sections. The flanges at the end of the waveguide sections have counterbores surrounding the waveguide tubes. When the sections are bolted together the counterbores form a groove that holds a fully annealed copper gasket. Each counterbore has a beveled step that is specially configured to insure the gasket forms a metal-to-metal vacuum seal without gaps or sharp edges. The resultant inner surface of the waveguide is smooth across the junctions between waveguide sections, and arcing is prevented.

  5. High-power Ka-band amplifier

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1993-01-01

    Development of a high-power tube suitable to power a Ka-band (34.5-GHz) antenna transmitter located at the Goldstone, California, tracking station is continuing. The University of Maryland Laboratory for Plasma Research and JPL are conducting a joint effort to test the feasibility of phase locking a second-harmonic gyrotron both by direct injection at the output cavity and by using a priming cavity to bunch the electrons in the beam. This article describes several design options and the results of computer simulation testing.

  6. Operation of high power converters in parallel

    NASA Technical Reports Server (NTRS)

    Decker, D. K.; Inouye, L. Y.

    1993-01-01

    High power converters that are used in space power subsystems are limited in power handling capability due to component and thermal limitations. For applications, such as Space Station Freedom, where multi-kilowatts of power must be delivered to user loads, parallel operation of converters becomes an attractive option when considering overall power subsystem topologies. TRW developed three different unequal power sharing approaches for parallel operation of converters. These approaches, known as droop, master-slave, and proportional adjustment, are discussed and test results are presented.

  7. CLIC RF High Power Production Testing Program

    SciTech Connect

    Syratchev, I.; Riddone, G.; Tantawi, S.G.; /SLAC

    2011-11-02

    The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production ({approx} 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses, makes the PETS design rather unique and the operation very challenging. In the coming year, an intense PETS testing program will be implemented. The target is to demonstrate the full performance of the PETS operation. The testing program overview and test results available to date are presented.

  8. High power diode pumped alkali vapor lasers

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Krupke, B.

    2008-05-01

    Diode pumped alkali lasers have developed rapidly since their first demonstration. These lasers offer a path to convert highly efficient, but relatively low brightness, laser diodes into a single high power, high brightness beam. General Atomics has been engaged in the development of DPALs with scalable architectures. We have examined different species and pump characteristics. We show that high absorption can be achieved even when the pump source bandwidth is several times the absorption bandwidth. In addition, we present experimental results for both potassium and rubidium systems pumped with a 0.2 nm bandwidth alexandrite laser. These data show slope efficiencies of 67% and 72% respectively.

  9. A high-power xenon dimer excilamp

    NASA Astrophysics Data System (ADS)

    Lomaev, M. I.; Skakun, V. S.; Tarasenko, V. F.; Shitts, D. V.

    2006-06-01

    A high-power sealed-off excilamp operating on xenon dimers excited by a barrier discharge and emitting in the vacuum ultraviolet spectral range (λ ˜ 172 nm) has been designed, constructed, and tested. The lamp comprises six quartz tubes (emitters) and has a total radiating surface area of 20 × 20 = 400 cm2. The average output power density radiated from the surface of each emitter exceeds 120 mW/cm2. The total output power of the excilamp immediately upon discharge ignition exceeds 50 W.

  10. Advances in industrial high-power lasers

    NASA Astrophysics Data System (ADS)

    Schlueter, Holger

    2005-03-01

    Four major types of laser sources are used for material processing. Excluding Excimer lasers, this paper focuses on advances in High Power CO2 lasers, Solid State Lasers and Diode Lasers. Because of their unrivaled cost to brightness relationship the fast axial flow CO2 laser remains unrivaled for flat-sheet laser cutting. Adding approximately a kW of output power ever four years, this laser type has been propelling the entire sheet metal fabrication industry for the last two decades. Very robust, diffusion cooled annular discharge CO2 lasers with 2kW output power have enabled robot mounted lasers for 3D applications. Solid State Lasers are chosen mainly because of the option of fiber delivery. Industrial applications still rely on lamp-pumped Nd:YAG lasers with guaranteed output powers of 4.5 kW at the workpiece. The introduction of the diode pumped Thin Disc Laser 4.5 kW laser enables new applications such as the Programmable Focus Optics. Pumping the Thin Disc Laser requires highly reliable High Power Diode Lasers. The necessary reliability can only be achieved in a modern, automated semiconductor manufacturing facility. For Diode Lasers, electro-optical efficiencies above 65% are as important as the passivation of the facets to avoid Burn-In power degradation.

  11. Early history of high-power lasers

    NASA Astrophysics Data System (ADS)

    Sutton, George W.

    2002-02-01

    This paper gives the history of the invention and development of early high power lasers, to which the author contributed and had personal knowledge. The earliest hint that a high power laser could be built came from the electric CO2-N2-He laser of Javan. It happened that the director of the Avco-Everett Research Laboratory had written his Ph.D. dissertation on the deactivation of the vibrational excitation of N2 in an expanding flow under Edward Teller, then at Columbia Univ. The director then started an in-house project to determine if gain could be achieved in a mixture similar to Javan's by means of a shock tunnel where a shock heated mixture of N2, CO2, and He gas was expanded through a supersonic nozzle into a cavity. This concept was named by the author as the gasdynamic laser (GDL). The paper traces the history of the initial gain measurements, the Mark II laser, the RASTA laser, the Tri-Service laser, its troubles and solutions, the United Technology's XLD gasdynamic laser, and their ALL laser. The history of the coastal Crusader will also be mentioned. Also discussed are the early experiments on a combustion-driven chemical laser, and its subsequent rejection by the director.

  12. Optimized VCSELs for high-power arrays

    NASA Astrophysics Data System (ADS)

    Moench, Holger; Kolb, Johanna S.; Engelhardt, Andreas P.; Gerlach, Philipp; Jaeger, Roland; Pollmann-Retsch, Jens; Weichmann, Ulrich; Witzigmann, Bernd

    2014-02-01

    High-power VCSEL systems with multi kilowatt output power require a good electro-optical efficiency at the point of operation i.e. at elevated temperature. The large number of optimization parameters can be structured in a way that separates system and assembly considerations from the minimization of electrical and optical losses in the epitaxially grown structure. Temperature dependent functions for gain parameters, internal losses and injection efficiency are derived from a fit to experimental data. The empirical description takes into account diameter dependent effects like current spreading or temperature dependent ones like voltage drops over hetero-interfaces in the DBR mirrors. By evaluating experimental measurements of the light output and voltage characteristics over a large range of temperature and diameter, wafer-characteristic parameters are extracted allowing to predict the performance of VCSELs made from this material in any array and assembly configuration. This approach has several beneficial outcomes: Firstly, it gives a general description of a VCSEL independent of its geometry, mounting and detuning, secondly, insights into the structure and the underlying physics can be gained that lead to the improvement potential of the structure and thirdly the performance of the structure in arrays and modules can be predicted. Experimental results validate the approach and demonstrate the significantly improved VCSEL efficiency and the benefit in high power systems.

  13. High power Ka band TWT amplifier

    SciTech Connect

    Golkowski, C.; Ivers, J.D.; Nation, J.A.; Wang, P.; Schachter, L.

    1999-07-01

    Two high power 35 GHz TWT amplifiers driven by a relativistic pencil, 850 kV, 200A electron beam have been assembled and tested. The first had a dielectric slow wave structure and was primarily used to develop diagnostics, and to gain experience in working with high power systems in Ka band. The source of the input power for the amplifier was a magnetron producing a 30 kW, 200ns long pulse of which 10 kW as delivered to the experiment. The 30 cm long dielectric (Teflon) amplifier produced output power levels of about 1 MW with a gain of about 23 dB. These results are consistent with expectations from PIC code simulations for this arrangement. The second amplifier, which is a single stage disk loaded slow wave structure, has been designed. It consists of one hundred uniform cells with two sets of ten tapered calls at the ends to lower the reflection coefficient. The phase advance per cell is {pi}/2. The amplifier passband extends from 28 to 40 GHz. It is designed to increase the output power to about 20 MW. The amplifier is in construction and will be tested in the near future. Details of the design of both systems will be provided and initial results from the new amplifier presented.

  14. The future of high power laser techniques

    NASA Astrophysics Data System (ADS)

    Poprawe, Reinhart; Loosen, Peter; Hoffmann, Hans-Dieter

    2007-05-01

    High Power Lasers have been used for years in corresponding applications. Constantly new areas and new processes have been demonstrated, developed and transferred to fruitful use in industry. With the advent of diode pumped solid state lasers in the multi-kW-power regime at beam qualities not far away from the diffraction limit, a new area of applicability has opened. In welding applications speeds could be increased and systems could be developed with higher efficiently leading also to new perspectives for increased productivity, e.g. in combined processing. Quality control is increasingly demanded by the applying industries, however applications still are rare. Higher resolution of coaxial process control systems in time and space combined with new strategies in signal processing could give rise to new applications. The general approach described in this paper emphasizes the fact, that laser applications can be developed more efficiently, more precisely and with higher quality, if the laser radiation is tailored properly to the corresponding application. In applying laser sources, the parameter ranges applicable are by far wider and more flexible compared to heat, mechanical or even electrical energy. The time frame ranges from several fs to continuous wave and this spans approximately 15 orders of magnitude. Spacewise, the foci range from several µm to cm and the resulting intensities suitable for materials processing span eight orders of magnitude from 10 3 to 10 11 W/cm2. In addition to space (power, intensity) and time (pulse) the wavelength can be chosen as a further parameter of optimization. As a consequence, the resulting new applications are vast and can be utilized in almost every market segment of our global economy (Fig. 1). In the past and only partly today, however, this flexibility of laser technology is not exploited in full in materials processing, basically because in the high power regime the lasers with tailored beam properties are not

  15. High power time domain terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Graber, Benjamin

    Terahertz (THz) has become a strong area for scientific research and commercial application in recent years. This research group has redesigned and optimized a THz photoconductive antenna, which currently operates with approximately 10x the power of a commercial antenna. It has been determined by this research that the THz signal emitted from a photoconductive antenna consists of coherent and incoherent signals. In addition to the improvement of the THz photoconductive antenna, I have optimized an electro optic THz detection system by characterizing the field dependency of an electro optic crystal, which enabled me to estimate the THz electric field strength. The high power THz source and optimized detection system were combined into a high power, high resolution time domain THz spectrometer. This spectrometer was used to conduct original measurements of the THz spectrum of water vapor, ionized air, and various chemical vapor including explosives. Most of these measurements were only possible with our improved THz spectrometer. In order to understand ionized air, an additional study was carried out to explore the ionization of several gases (e.g. N2, O2, Ar, CO2, and water vapor) which were ionized by radioactive isotopes. This unique study found that in addition to dose rate, the gamma energy of the radioactive isotopes and the sequential ionization levels of gases affect the equilibrium ion densities of these gases. This effect was especially pronounced for argon gas. The study of ion dynamics in gases has lead to the development of a prototype for stand-off detection and identification of radioactive isotopes. This prototype, despite being simple in design, can detect isotopes faster and more cheaply than a conventional gamma ray spectrometer. Throughout this thesis research I have successfully developed a high power, high resolution terahertz spectrometer and demonstrated that with the spectrometer I could identify characteristic resonances of water vapor, some

  16. E3000 High Power SADM development

    NASA Astrophysics Data System (ADS)

    Bamford, Steve G.; McMahon, Paul

    2003-09-01

    Astrium UK has been actively involved in the study, design, development, manufacture and test of Solar Array Drive Mechanisms (SADMs) and Bearing and Power Transfer Assemblies (BAPTAs) since the early 1970s having delivered 105 of these mechanisms to 22 spacecraft programs. As a result Astrium UK has accumulated in excess of 700 years of failure free SADM operation in-orbit. During that period power transfer requirements have grown steadily from below 1kW to 9.9kW and beyond. With this increase in power handling capability comes the associated problem of handling and dissipating the heat being generated within the SADM. The Eurostar 2000 family of SADMs were designed to handle up to 5.6kW for the E2000 family of spacecraft but the High Power SADM was conceived to meet the needs of the much bigger Eurostar 3000 family of spacecraft that could potentially grow to 15kW.

  17. Modulation instability in high power laser amplifiers.

    PubMed

    Rubenchik, Alexander M; Turitsyn, Sergey K; Fedoruk, Michail P

    2010-01-18

    The modulation instability (MI) is one of the main factors responsible for the degradation of beam quality in high-power laser systems. The so-called B-integral restriction is commonly used as the criteria for MI control in passive optics devices. For amplifiers the adiabatic model, assuming locally the Bespalov-Talanov expression for MI growth, is commonly used to estimate the destructive impact of the instability. We present here the exact solution of MI development in amplifiers. We determine the parameters which control the effect of MI in amplifiers and calculate the MI growth rate as a function of those parameters. The safety range of operational parameters is presented. The results of the exact calculations are compared with the adiabatic model, and the range of validity of the latest is determined. We demonstrate that for practical situations the adiabatic approximation noticeably overestimates MI. The additional margin of laser system design is quantified.

  18. High-Power Options for LANSCE

    SciTech Connect

    Garnett, Robert W.

    2011-01-01

    The LANSCE linear accelerator at Los Alamos National Laboratory has a long history of successful beam operations at 800 kW. We have recently studied options for restoration of high-power operations including approaches for increasing the performance to multi-MW levels. In this paper we will discuss the results of this study including the present limitations of the existing accelerating structures at LANSCE, and the high-voltage and RF systems that drive them. Several options will be discussed and a preferred option will be presented that will enable the first in a new generation of scientific facilities for the materials community. The emphasis of this new facility is 'Matter-Radiation Interactions in Extremes' (MaRIE) which will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges.

  19. High power density solid oxide fuel cells

    DOEpatents

    Pham, Ai Quoc; Glass, Robert S.

    2004-10-12

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  20. High power performance limits of fiber components

    NASA Astrophysics Data System (ADS)

    Holehouse, Nigel; Magné, Julien; Auger, Mathieu

    2015-03-01

    High power combiners are essential for practical fiber lasers, recent developments in pump technology has increased the available brightness and power of pumps significantly, enabling multi kW lasers and pushing combiner designs to new limits. I will present the challenges, measurements and some solutions to these issues. Traditional calculations for combiners underestimate the issues associated with the `tails' of the pump NA distribution, losses in fully filled combiners increase rapidly as pump NA blooms, and subsequent heating effects dominate the combiner's power handling. Acrylate coated pump fibers are reaching their limits and devices and measurements on double clad pump combiners with losses <0.05dB, will be presented enabling multi kW operation, The use of triple clad fibers in the gain section will discussed as a solution for multi kW applications. Results on ultra-low background loss FBG's will be presented, along with developed measurement techniques.

  1. Deformable mirror for high power laser applications

    NASA Astrophysics Data System (ADS)

    Mrň; a, Libor; Sarbort, Martin; Hola, Miroslava

    2015-01-01

    The modern trend in high power laser applications such as welding, cutting and surface hardening lies in the use of solid-state lasers. The output beam of these lasers is characterized by a Gaussian intensity distribution. However, the laser beams with different intensity distributions, e.g. top-hat, are preferable in various applications. In this paper we present a new type of deformable mirror suitable for the corresponding laser beam shaping. The deformation of the mirror is achieved by an underlying array of actuators and a pressurized coolant that also provides the necessary cooling. We describe the results of the surface shape measurement using a 3D scanner for different settings of actuators. Further, we show the achieved intensity distributions measured by a beam profiler for a low power laser beam reflected from the mirror.

  2. Feedthrough terminal for high-power cell

    DOEpatents

    Kaun, T.D.

    1982-05-28

    A feedthrough terminal for a high power electrochemical storage cell providing low resistance coupling to the conductive elements therein while isolating the terminal electrode from the highly corrosive environment within the cell is disclosed. A large diameter, cylindrical copper electrode is enclosed in a stainless steel tube with a BN powder feedthrough seal maintained around the stainless steel tube by means of facing insulative bushings and an outer sleeve. One end of the copper conductor is silver-brazed directly to a flat, butterfly bus bar within the cell, with the adjacent end of the surrounding outer feedthrough sleeve welded to the bus bar. A threaded seal is fixedly positioned on a distal portion of the stainless steel tube immediately adjacent the distal insulative bushing so as to compress the feedthrough seal in tight fitting relation around the stainless steel tube in providing a rugged, leak-proof electrical feedthrough terminal for the power cell.

  3. Tapered fiber based high power random laser.

    PubMed

    Zhang, Hanwei; Du, Xueyuan; Zhou, Pu; Wang, Xiaolin; Xu, Xiaojun

    2016-04-18

    We propose a novel high power random fiber laser (RFL) based on tapered fiber. It can overcome the power scaling limitation of RFL while maintaining good beam quality to a certain extent. An output power of 26.5 W has been achieved in a half-open cavity with one kilometer long tapered fiber whose core diameter gradually changes from 8 μm to 20 μm. The steady-state light propagation equations have been modified by taking into account the effective core area to demonstrate the tapered RFL through numerical calculations. The numerical model effectively describes the power characteristics of the tapered fiber based RFL, and both the calculating and experimental results show higher power exporting potential compared with the conventional single mode RFL. PMID:27137338

  4. Microstructured fibers for high power applications

    NASA Astrophysics Data System (ADS)

    Baggett, J. C.; Petrovich, M. N.; Hayes, J. R.; Finazzi, V.; Poletti, F.; Amezcua, R.; Broderick, N. G. R.; Richardson, D. J.; Monro, T. M.; Salter, P. L.; Proudley, G.; O'Driscoll, E. J.

    2005-10-01

    Fiber delivery of intense laser radiation is important for a broad range of application sectors, from medicine through to industrial laser processing of materials, and offers many practical system design and usage benefits relative to free space solutions. Optical fibers for high power transmission applications need to offer low optical nonlinearity and high damage thresholds. Single-mode guidance is also often a fundamental requirement for the many applications in which good beam quality is critical. In recent years, microstructured fiber technology has revolutionized the dynamic field of optical fibers, bringing with them a wide range of novel optical properties. These fibers, in which the cladding region is peppered with many small air holes, are separated into two distinct categories, defined by the way in which they guide light: (1) index-guiding holey fibers (HFs), in which the core is solid and light is guided by a modified form of total internal reflection, and (2) photonic band-gap fibers (PBGFs) in which guidance in a hollow core can be achieved via photonic band-gap effects. Both of these microstructured fiber types offer attractive qualities for beam delivery applications. For example, using HF technology, large-mode-area, pure silica fibers with robust single-mode guidance over broad wavelength ranges can be routinely fabricated. In addition, the ability to guide light in an air-core within PBGFs presents obvious power handling advantages. In this paper we review the fundamentals and current status of high power, high brightness, beam delivery in HFs and PBGFs, and speculate as to future prospects.

  5. Aluminum as anode for energy storage and conversion: a review

    NASA Astrophysics Data System (ADS)

    Li, Qingfeng; Bjerrum, Niels J.

    Aluminum has long attracted attention as a potential battery anode because of its high theoretical voltage and specific energy. The protective oxide layer on the aluminum surface is however detrimental to the battery performance, contributing to failure to achieve the reversible potential and causing the delayed activation of the anode. By developing aluminum alloys as anodes and solution additives to electrolytes, a variety of aluminum batteries have been extensively investigated for various applications. From molten salt and other non-aqueous electrolytes, aluminum can be electrodeposited and therefore be suitable for developing rechargable batteries. Considerable efforts have been made to develop secondary aluminum batteries of high power density. In the present paper, these research activities are reviewed, including aqueous electrolyte primary batteries, aluminum-air batteries and molten salt secondary batteries.

  6. Robust cladding light stripper for high-power fiber lasers using soft metals.

    PubMed

    Babazadeh, Amin; Nasirabad, Reza Rezaei; Norouzey, Ahmad; Hejaz, Kamran; Poozesh, Reza; Heidariazar, Amir; Golshan, Ali Hamedani; Roohforouz, Ali; Jafari, S Naser Tabatabaei; Lafouti, Majid

    2014-04-20

    In this paper we present a novel method to reliably strip the unwanted cladding light in high-power fiber lasers. Soft metals are utilized to fabricate a high-power cladding light stripper (CLS). The capability of indium (In), aluminum (Al), tin (Sn), and gold (Au) in extracting unwanted cladding light is examined. The experiments show that these metals have the right features for stripping the unwanted light out of the cladding. We also find that the metal-cladding contact area is of great importance because it determines the attenuation and the thermal load on the CLS. These metals are examined in different forms to optimize the contact area to have the highest possible attenuation and avoid localized heating. The results show that sheets of indium are very effective in stripping unwanted cladding light.

  7. Prospects for using high power x-rays as a volumetric heat source

    SciTech Connect

    Rosenberg, R.A.; Farrell, W.; Ma, Q.

    1997-09-01

    Third-generation, high-intensity, x-ray synchrotron radiation sources are capable of producing high heat-flux x-ray beams. In many applications finding ways to handle these powers is viewed as a burden. However, there are some technological applications where the deep penetration length of the x-rays may find beneficial uses as a volumetric heat source. In this paper the authors discuss the prospects for using high power x-rays for volumetric heating and report some recent experimental results. The particular applications they focus on are welding and surface heat treatment. The radiation source is an undulator at the Advanced Photon Source (APS). Results of preliminary tests on aluminum, aluminum metal matrix composites, and steel will be presented.

  8. Interaction of a High-Power Laser Beam with Metal Sheets

    SciTech Connect

    Boley, C D; Cutter, K P; Fochs, S N; Pax, P H; Rotter, M D; Rubenchik, A M; Yamamoto, R M

    2009-06-24

    Experiments with a high-power laser beam directed onto thin aluminum sheets, with a large spot size, demonstrate that airflow produces a strong enhancement of the interaction. The enhancement is explained in terms of aerodynamic effects. As laser heating softens the material, the airflow-induced pressure difference between front and rear faces causes the metal to bulge into the beam. The resulting shear stresses rupture the material and remove it at temperatures well below the melting point. The material heating is shown to conform to an elementary model. We present an analytic model of elastic bulging. Scaling with respect to spot size, wind speed, and material parameters is determined.

  9. Analysis of a passive heat sink for temperature stabilization of high-power LED bulbs

    NASA Astrophysics Data System (ADS)

    Balvís, Eduardo; Bendaña, Ricardo; Michinel, Humberto; Fernández de Córdoba, Pedro; Paredes, Angel

    2015-04-01

    In this paper we present a numerical analysis and experimental measurements of the temperature stabilization of high-power LED chips that we have obtained by employing an aluminum passive heat sink, designed to be used in a compact light bulb configuration. We demonstrate that our system keeps the temperature of the LED chip well-below 70° C yielding long-term operation of the device. Our simulations have been performed for a low-cost device ready to install in public streetlights. The experimental measurements performed in different configurations show a nice agreement with the numerical calculations.

  10. Aluminum phosphide

    Integrated Risk Information System (IRIS)

    Aluminum phosphide ; CASRN 20859 - 73 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  11. High-Power Magnetoplasmadynamic Thruster Being Developed

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.

    2001-01-01

    High-power electromagnetic thrusters have been proposed as primary in-space propulsion options for several of the bold new interplanetary and deep space missions envisioned by the Human Exploration and Development of Space (HEDS) Strategic Enterprise. As the lead center for electric propulsion, the NASA Glenn Research Center is actively involved in the design, development, and testing of high-power electromagnetic technologies to meet these demanding mission requirements. One concept of particular interest is the magnetoplasmadynamic (MPD) thruster, shown schematically in the preceding figure. In its basic form, the MPD thruster consists of a central cathode surrounded by a concentric cylindrical anode. A high-current arc is struck between the anode and cathode, which ionizes and accelerates a gas (plasma) propellant. In the self-field version of the thruster, an azimuthal magnetic field generated by the current returning through the cathode interacts with the radial discharge current flowing through the plasma to produce an axial electromagnetic body force, providing thrust. In applied field-versions of the thruster, a magnetic field coil surrounding the anode is used to provide additional radial and axial magnetic fields that can help stabilize and accelerate the plasma propellant. The following figure shows an experimental megawatt-class MPD thruster developed at Glenn. The MPD thruster is fitted inside a magnetic field coil, which in turn is mounted on a thrust stand supported by thin metal flexures. A calibrated position transducer is used to determine the force provided by the thruster as a function of thrust stand displacement. Power to the thruster is supplied by a 250-kJ capacitor bank, which provides up to 30- MW to the thruster for a period of 2 msec. This short period of time is sufficient to establish thruster performance similar to steady-state operation, and it allows a number of thruster designs to be quickly and economically evaluated. In concert

  12. Functionally strain-graded nanoscoops for high power Li-ion battery anodes.

    PubMed

    Krishnan, Rahul; Lu, Toh-Ming; Koratkar, Nikhil

    2011-02-01

    Lithium-ion batteries show poor performance for high power applications involving ultrafast charging/discharging rates. Here we report a functionally strain-graded carbon-aluminum-silicon anode architecture that overcomes this drawback. It consists of an array of nanostructures each comprising an amorphous carbon nanorod with an intermediate layer of aluminum that is finally capped by a silicon nanoscoop on the very top. The gradation in strain arises from graded levels of volumetric expansion in these three materials on alloying with lithium. The introduction of aluminum as an intermediate layer enables the gradual transition of strain from carbon to silicon, thereby minimizing the mismatch at interfaces between differentially strained materials and enabling stable operation of the electrode under high-rate charge/discharge conditions. At an accelerated current density of ∼51.2 A/g (i.e., charge/discharge rate of ∼40C), the strain-graded carbon-aluminum-silicon nanoscoop anode provides average capacities of ∼412 mAh/g with a power output of ∼100 kW/kg(electrode) continuously over 100 charge/discharge cycles.

  13. Improved Collectors for High Power Gyrotrons

    SciTech Connect

    Ives, R. Lawrence; Singh, Amarjit; Read, Michael; Borchard, Phillipp; Neilson, Jeff

    2009-05-20

    High power gyrotrons are used for electron cyclotron heating, current drive and parasitic mode suppression in tokamaks for fusion energy research. These devices are crucial for successful operation of many research programs around the world, including the ITER program currently being constructed in France. Recent gyrotron failures resulted from cyclic fatigue of the copper material used to fabricated the collectors. The techniques used to collect the spent beam power is common in many gyrotrons produced around the world. There is serious concern that these tubes may also be at risk from cyclic fatigue. This program addresses the cause of the collector failure. The Phase I program successfully demonstrated feasibility of a mode of operation that eliminates the cyclic operation that caused the failure. It also demonstrated that new material can provide increased lifetime under cyclic operation that could increase the lifetime by more than on order of magnitude. The Phase II program will complete that research and develop a collector that eliminates the fatigue failures. Such a design would find application around the world.

  14. Fibrous zinc anodes for high power batteries

    NASA Astrophysics Data System (ADS)

    Zhang, X. Gregory

    This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc-air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc-air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc-air battery was used to power an electric bicycle and demonstrated good results.

  15. On reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.

    2016-01-01

    High power impulse magnetron sputtering (HiPIMS) is an ionized physical vapor deposition (IPVD) technique that is particularly promising for reactive sputtering applications. However, there are few issues that have to be resolved before the full potential of this technique can be realized. Here we give an overview of the key experimental findings for the reactive HiPIMS discharge. An increase in the discharge current is commonly observed with increased partial pressure of the reactive gas or decreased repetition pulse frequency. There are somewhat conflicting claims regarding the hysteresis effect in the reactive HiPIMS discharge as some report reduction or elimination of the hysteresis effect while others claim a feedback control is essential. The ion energy distribution of the metal ion and the atomic ion of the reactive gas are similar and extend to very high energies while the ion energy distribution of the working gas and the molecular ion of the reactive gas are similar and are much less energetic.

  16. High frequency, high power capacitor development

    NASA Technical Reports Server (NTRS)

    White, C. W.; Hoffman, P. S.

    1983-01-01

    A program to develop a special high energy density, high power transfer capacitor to operate at frequency of 40 kHz, 600 V rms at 125 A rms plus 600 V dc bias for space operation. The program included material evaluation and selection, a capacitor design was prepared, a thermal analysis performed on the design. Fifty capacitors were manufactured for testing at 10 kHz and 40 kHz for 50 hours at Industrial Electric Heating Co. of Columbus, Ohio. The vacuum endurance test used on environmental chamber and temperature plate furnished by Maxwell. The capacitors were energized with a special power conditioning apparatus developed by Industrial Electric Heating Co. Temperature conditions of the capacitors were monitored by IEHCo test equipment. Successful completion of the vacuum endurance test series confirmed achievement of the main goal of producing a capacitor or reliable operation at high frequency in an environment normally not hospitable to electrical and electronic components. The capacitor developed compared to a typical commercial capacitor at the 40 kHz level represents a decrease in size and weight by a factor of seven.

  17. High power linear pulsed beam annealer

    DOEpatents

    Strathman, Michael D.; Sadana, Devendra K.; True, Richard B.

    1983-01-01

    A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons. A second coil surrounding the second drift tube maintains the electron beam focused about the axis of the second drift tube and compresses the electron beam to the area of the target. The target holder can be adjusted to position the target where the cross section of the beam matches the area of the target.

  18. High power THz sources for nonlinear imaging

    NASA Astrophysics Data System (ADS)

    Tekavec, Patrick F.; Kozlov, Vladimir G.

    2014-02-01

    Many biological and chemical compounds have unique absorption features in the THz (0.1 - 10 THz) region, making the use of THz waves attractive for imaging in defense, security, biomedical imaging, and monitoring of industrial processes. Unlike optical radiation, THz frequencies can pass through many substances such as paper, clothing, ceramic, etc. with little attenuation. The use of currently available THz systems is limited by lack of highpower, sources as well as sensitive detectors and detector arrays operating at room temperature. Here we present a novel, high power THz source based on intracavity downconverison of optical pulses. The source delivers 6 ps pulses at 1.5 THz, with an average power of >300 μW and peak powers >450 mW. We propose an imaging method based on frequency upconverison that is ideally suited to use the narrow bandwidth and high peak powers produced by the source. By upconverting the THz image to the infrared, commercially available detectors can be used for real time imaging.

  19. High frequency, high power capacitor development

    NASA Astrophysics Data System (ADS)

    White, C. W.; Hoffman, P. S.

    1983-03-01

    A program to develop a special high energy density, high power transfer capacitor to operate at frequency of 40 kHz, 600 V rms at 125 A rms plus 600 V dc bias for space operation. The program included material evaluation and selection, a capacitor design was prepared, a thermal analysis performed on the design. Fifty capacitors were manufactured for testing at 10 kHz and 40 kHz for 50 hours at Industrial Electric Heating Co. of Columbus, Ohio. The vacuum endurance test used on environmental chamber and temperature plate furnished by Maxwell. The capacitors were energized with a special power conditioning apparatus developed by Industrial Electric Heating Co. Temperature conditions of the capacitors were monitored by IEHCo test equipment. Successful completion of the vacuum endurance test series confirmed achievement of the main goal of producing a capacitor or reliable operation at high frequency in an environment normally not hospitable to electrical and electronic components. The capacitor developed compared to a typical commercial capacitor at the 40 kHz level represents a decrease in size and weight by a factor of seven.

  20. High power THz sources for nonlinear imaging

    SciTech Connect

    Tekavec, Patrick F.; Kozlov, Vladimir G.

    2014-02-18

    Many biological and chemical compounds have unique absorption features in the THz (0.1 - 10 THz) region, making the use of THz waves attractive for imaging in defense, security, biomedical imaging, and monitoring of industrial processes. Unlike optical radiation, THz frequencies can pass through many substances such as paper, clothing, ceramic, etc. with little attenuation. The use of currently available THz systems is limited by lack of highpower, sources as well as sensitive detectors and detector arrays operating at room temperature. Here we present a novel, high power THz source based on intracavity downconverison of optical pulses. The source delivers 6 ps pulses at 1.5 THz, with an average power of >300 μW and peak powers >450 mW. We propose an imaging method based on frequency upconverison that is ideally suited to use the narrow bandwidth and high peak powers produced by the source. By upconverting the THz image to the infrared, commercially available detectors can be used for real time imaging.

  1. High-power LED package requirements

    NASA Astrophysics Data System (ADS)

    Wall, Frank; Martin, Paul S.; Harbers, Gerard

    2004-01-01

    Power LEDs have evolved from simple indicators into illumination devices. For general lighting applications, where the objective is to light up an area, white LED arrays have been utilized to serve that function. Cost constraints will soon drive the industry to provide a discrete lighting solution. Early on, that will mean increasing the power densities while quantum efficiencies are addressed. For applications such as automotive headlamps & projection, where light needs to be tightly collimated, or controlled, arrays of die or LEDs will not be able to satisfy the requirements & limitations defined by etendue. Ultimately, whether a luminaire requires a small source with high luminance, or light spread over a general area, economics will force the evolution of the illumination LED into a compact discrete high power package. How the customer interfaces with this new package should be an important element considered early on in the design cycle. If an LED footprint of adequate size is not provided, it may prove impossible for the customer, or end user, to get rid of the heat in a manner sufficient to prevent premature LED light output degradation. Therefore it is critical, for maintaining expected LED lifetime & light output, that thermal performance parameters be defined, by design, at the system level, which includes heat sinking methods & interface materials or methdology.

  2. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, Lloyd A.; Dane, Clifford B.

    1993-01-01

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  3. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, L.A.; Dane, C.B.

    1993-08-24

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  4. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  5. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  6. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  7. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  8. 14 CFR 101.25 - Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Power Rockets and Class 3-Advanced High Power Rockets. 101.25 Section 101.25 Aeronautics and Space... OPERATING RULES MOORED BALLOONS, KITES, AMATEUR ROCKETS AND UNMANNED FREE BALLOONS Amateur Rockets § 101.25 Operating limitations for Class 2-High Power Rockets and Class 3-Advanced High Power Rockets. When...

  9. 3-D Printed High Power Microwave Magnetrons

    NASA Astrophysics Data System (ADS)

    Jordan, Nicholas; Greening, Geoffrey; Exelby, Steven; Gilgenbach, Ronald; Lau, Y. Y.; Hoff, Brad

    2015-11-01

    The size, weight, and power requirements of HPM systems are critical constraints on their viability, and can potentially be improved through the use of additive manufacturing techniques, which are rapidly increasing in capability and affordability. Recent experiments on the UM Recirculating Planar Magnetron (RPM), have explored the use of 3-D printed components in a HPM system. The system was driven by MELBA-C, a Marx-Abramyan system which delivers a -300 kV voltage pulse for 0.3-1.0 us, with a 0.15-0.3 T axial magnetic field applied by a pair of electromagnets. Anode blocks were printed from Water Shed XC 11122 photopolymer using a stereolithography process, and prepared with either a spray-coated or electroplated finish. Both manufacturing processes were compared against baseline data for a machined aluminum anode, noting any differences in power output, oscillation frequency, and mode stability. Evolution and durability of the 3-D printed structures were noted both visually and by tracking vacuum inventories via a residual gas analyzer. Research supported by AFOSR (grant #FA9550-15-1-0097) and AFRL.

  10. Facet engineering of high power single emitters

    NASA Astrophysics Data System (ADS)

    Yanson, Dan; Levi, Moshe; Shamay, Moshe; Tesler, Renana; Rappaport, Noam; Don, Yaroslav; Karni, Yoram; Schnitzer, Itzhak; Sicron, Noam; Shusterman, Sergey

    2011-03-01

    The ever increasing demand for high-power, high-reliability operation of single emitters at 9xx nm wavelengths requires the development of laser diodes with improved facet regions immune to both catastrophic and wear-out failure modes. In our study, we have evaluated several laser facet definition technologies in application to 90 micron aperture single emitters in asymmetric design (In)GaAs/AlGaAs based material emitting at 915, 925 and 980nm. A common epitaxy and emitter design makes for a straightforward comparison of the facet technologies investigated. Our study corroborates a clear trend of increasing difficulty in obtaining reliable laser operation from 980nm down to 915nm. At 980nm, one can employ dielectric facet passivation with a pre-clean cycle delivering a device lifetime in excess of 3,000 hours at increasing current steps. At 925nm, quantum-well intermixing can be used to define non-absorbing mirrors giving good device reliability, albeit with a large efficiency penalty. Vacuum cleaved emitters have delivered excellent reliability at 915nm, and can be expected to perform just as well at 925 and 980nm. Epitaxial regrowth of laser facets is under development and has yet to demonstrate an appreciable reliability improvement. Only a weak correlation between start-of-life catastrophic optical mirror damage (COMD) levels and reliability was established. The optimized facet design has delivered maximum powers in excess of 19 MW/sq.cm (rollover limited) and product-grade 980nm single emitters with a slope efficiency of >1 W/A and a peak efficiency of >60%. The devices have accumulated over 1,500 hours of CW operation at 11W. A fiber-coupled device emits 10W ex-fiber with 47% efficiency.

  11. Hybrid high power femtosecond laser system

    NASA Astrophysics Data System (ADS)

    Trunov, V. I.; Petrov, V. V.; Pestryakov, E. V.; Kirpichnikov, A. V.

    2006-01-01

    Design of a high-power femtosecond laser system based on hybrid chirped pulse amplification (CPA) technique developed by us is presented. The goal of the hybrid principle is the use of the parametric and laser amplification methods in chirped pulse amplifiers. It makes it possible to amplify the low-cycle pulses with a duration of <= fs to terawatt power with a high contrast and high conversion efficiency of the pump radiation. In a created system the Ti:Sapphire laser with 10 fs pulses at 810 nm and output energy about 1-3 nJ will be used like seed source. The oscillator pulses were stretched to duration of about 500 ps by an all-reflective grating stretcher. Then the stretched pulses are injected into a nondegenerate noncollinear optical parametric amplifier (NOPA) on the two BBO crystals. After amplification in NOPA the residual pump was used in a bow-tie four pass amplifier with hybrid active medium (based on Al II0 3:Ti 3+ and BeAl IIO 4:Ti 3+ crystals). The final stage of the amplification system consists of two channels, namely NIR (820 nm) and short-VIS (410 nm). Numerical simulation has shown that the terawatt level of output power can be achieved also in a short-VIS channel at the pumping of the double-crystal BBO NOPA by the radiation of the fourth harmonic of the Nd:YAG laser at 266 nm. Experimentally parametric amplification in BBO crystals of 30-50 fs pulses were investigated and optimized using SPIDER technique and single-shot autocomelator for the realization of shortest duration 40 fs.

  12. The Jefferson Lab High Power Light Source

    SciTech Connect

    James R. Boyce

    2006-01-01

    Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

  13. High Power Amplifier and Power Supply

    NASA Technical Reports Server (NTRS)

    Duong, Johnny; Stride, Scot; Harvey, Wayne; Haque, Inam; Packard, Newton; Ng, Quintin; Ispirian, Julie Y.; Waian, Christopher; Janes, Drew

    2008-01-01

    A document discusses the creation of a high-voltage power supply (HVPS) that is able to contain voltages up to -20 kV, keep electrical field strengths to below 200 V/mil (approximately equal to 7.87 kV/mm), and can provide a 200-nanosecond rise/fall time focus modulator swinging between cathode potential of 16.3 kV and -19.3 kV. This HVPS can protect the 95-GHz, pulsed extended interaction klystron (EIK) from arcs/discharges from all sources, including those from within the EIK fs vacuum envelope. This innovation has a multi-winding pulse transformer design, which uses new winding techniques to provide the same delays and rise/fall times (less than 10 nanoseconds) at different potential levels ranging from -20 kV to -16 kV. Another feature involves a high-voltage printed-wiring board that was corona-free at -20 kV DC with a 3- kV AC swing. The corona-free multilayer high-voltage board is used to simulate fields of less than 200 V/mil (approximately equal to 7.87 kV/mm) at 20 kV DC. Drive techniques for the modulator FETs (field-effect transistors) (four to 10 in a series) were created to change states (3,000-V swing) without abrupt steps, while still maintaining required delays and transition times. The packing scheme includes a potting mold to house a ten-stage modulator in the space that, in the past, only housed a four-stage modulator. Problems keeping heat down were solved using aluminum oxide substrate in the high-voltage section to limit temperature rise to less than 10 while withstanding -20 kV DC voltage and remaining corona-free.

  14. Surface alloying of silicon into aluminum substrate.

    SciTech Connect

    Xu, Z.

    1998-10-28

    Aluminum alloys that are easily castable tend to have lower silicon content and hence lower wear resistance. The use of laser surface alloying to improve the surface wear resistance of 319 and 320 aluminum alloys was examined. A silicon layer was painted onto the surface to be treated. A high power pulsed Nd:YAG laser with fiberoptic beam delivery was used to carry out the laser surface treatment to enhance the silicon content. Process parameters were varied to minimize the surface roughness from overlap of the laser beam treatment. The surface-alloyed layer was characterized and the silicon content was determined.

  15. The JLab high power ERL light source

    SciTech Connect

    G.R. Neil; C. Behre; S.V. Benson; M. Bevins; G. Biallas; J. Boyce; J. Coleman; L.A. Dillon-Townes; D. Douglas; H.F. Dylla; R. Evans; A. Grippo; D. Gruber; J. Gubeli; D. Hardy; C. Hernandez-Garcia; K. Jordan; M.J. Kelley; L. Merminga; J. Mammosser; W. Moore; N. Nishimori; E. Pozdeyev; J. Preble; R. Rimmer; Michelle D. Shinn; T. Siggins; C. Tennant; R. Walker; G.P. Williams and S. Zhang

    2005-03-19

    concerning the physics performance, design optimization, and operational limitations of such a first generation high power ERL light source.

  16. High power infrared QCLs: advances and applications

    NASA Astrophysics Data System (ADS)

    Patel, C. Kumar N.

    2012-01-01

    QCLs are becoming the most important sources of laser radiation in the midwave infrared (MWIR) and longwave infrared (LWIR) regions because of their size, weight, power and reliability advantages over other laser sources in the same spectral regions. The availability of multiwatt RT operation QCLs from 3.5 μm to >16 μm with wall plug efficiency of 10% or higher is hastening the replacement of traditional sources such as OPOs and OPSELs in many applications. QCLs can replace CO2 lasers in many low power applications. Of the two leading groups in improvements in QCL performance, Pranalytica is the commercial organization that has been supplying the highest performance QCLs to various customers for over four year. Using a new QCL design concept, the non-resonant extraction [1], we have achieved CW/RT power of >4.7 W and WPE of >17% in the 4.4 μm - 5.0 μm region. In the LWIR region, we have recently demonstrated QCLs with CW/RT power exceeding 1 W with WPE of nearly 10 % in the 7.0 μm-10.0 μm region. In general, the high power CW/RT operation requires use of TECs to maintain QCLs at appropriate operating temperatures. However, TECs consume additional electrical power, which is not desirable for handheld, battery-operated applications, where system power conversion efficiency is more important than just the QCL chip level power conversion efficiency. In high duty cycle pulsed (quasi-CW) mode, the QCLs can be operated without TECs and have produced nearly the same average power as that available in CW mode with TECs. Multiwatt average powers are obtained even in ambient T>70°C, with true efficiency of electrical power-to-optical power conversion being above 10%. Because of the availability of QCLs with multiwatt power outputs and wavelength range covering a spectral region from ~3.5 μm to >16 μm, the QCLs have found instantaneous acceptance for insertion into multitude of defense and homeland security applications, including laser sources for infrared

  17. High Power Flex-Propellant Arcjet Performance

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.

    2011-01-01

    implied nearly frozen flow in the nozzle and yielded performance ranges of 800-1100 sec for hydrogen and 400-600 sec for ammonia. Inferred thrust-to-power ratios were in the range of 30-10 lbf/MWe for hydrogen and 60-20 lbf/MWe for ammonia. Successful completion of this test series represents a fundamental milestone in the progression of high power arcjet technology, and it is hoped that the results may serve as a reliable touchstone for the future development of MW-class regeneratively-cooled flex-propellant plasma rockets.

  18. High Power Microwaves for Accelerator Applications*

    NASA Astrophysics Data System (ADS)

    Hirshfield, J. L.

    2004-05-01

    Realization of a future high-energy electron-positron collider rests upon many technological advancements, among which are high-power microwave amplifiers, and rf pulse compressors. In one scenario for the 0.5 TeV NLC, each linac requires about 1000, 75 MW, 11.4 GHz amplifiers furnishing peak powers of 75 MW in 1.6 mcs pulses at 120 Hz pps. Pulse compression to 0.4 mcs would result in a total rf peak power of over 400 GW. After a decade of intense development, SLAC has evidently reached the amplifier goal with the XP3 PPM klystron. Dual-mode double-delay-line pulse compression has demonstrated 4:1 compression to a peak output of 500 MW. These achievements help provide technological justification for NLC. Further justification rests with NLC's capability for a subsequent energy upgrade to 1.0-1.5 TeV. Nascent microwave technologies for the energy upgrade are discussed. These include an X-band magnicon, with double the output of a SLAC klystron: peak and average powers are predicted to reach 155 MW and 60 kW. Each magnicon could replace two SLAC klystrons, and operate with twice the pulse width. Therefore, an 8:1 pulse compressor is required. Active, efficient, rf pulse compression, with switching during the rf pulse could be provided by an externally-varied semiconductor, plasma, or ferroelectric switching element. Demonstration of an X-band magnicon, and of 10:1 X-band pulse compression using plasma switches is described. Prospects for higher efficiency rf pulse compression using ferroelectric switching elements is also described. A scenario for obtaining an energy upgrade to 2.0 TeV is outlined, based on use of 34-GHz technology in the inner halves of each linac. This option rests upon development of a 34-GHz magnicon amplifier, first results with which are described. *Sponsored by DoE, Division of High Energy Physics.

  19. High-power sources for EUV lithography: state of the art

    NASA Astrophysics Data System (ADS)

    Stamm, Uwe; Kleinschmidt, Juergen; Gaebel, Kai M.; Birner, Henry; Ahmad, Imtiaz; Bolshukhin, Denis; Brudermann, Jesko; Chinh, Tran Duc; Flohrer, Frank; Goetze, Sven; Hergenhan, Guido; Kloepfel, Diethard; Korobochko, Vladimir; Mader, Bjoern; Mueller, Rainer; Ringling, Jens; Schriever, Guido; Ziener, Christian

    2004-09-01

    The availability of extreme ultraviolet (EUV) light sources, measurement tools and integrated test systems is of major importance for the development of EUV lithography for use in high volume chip manufacturing which is expected to start in 2009. The estimates of cost of an EUV exposure tool in combination with sophisticated throughput models leads to a throughput of 120 wafers per hour necessary for economic use of EUV lithography. Concluding from that light sources are necessary which deliver an EUV output power of 115 W at 13.5 nm at the entrance of the illuminator system. The power requirement in combination with the required lifetimes of source components and collector optics make the source technology the most critical issue to be solved when developing EUV lithography. The present paper gives an update of the development status of EUV light sources at XTREME technologies, a joint venture of Lambda Physik AG, Goettingen, and Jenoptik LOS GmbH, Jena, Germany. Results on both laser produced plasma (LPP) and gas discharge produced plasma (GDPP), the two major technologies in EUV sources, are given. The LPP EUV sources use xenon-jet target systems and pulsed lasers with 500 W average power at up to 10 kHz developed at XTREME technologies. The maximum conversion efficiency from laser power into EUV in-band power is 1.0% into 2π solid angle. 2.0 W EUV radiation is generated at 13.5 nm in 2π sr solid angle. The small source volume of < 0.3 mm diameter will allow large collection angles of 5 sr. The intermediate focus power is estimated to 1 W. Collector mirror lifetime tests showed 5 million pulses lifetime without debris mitigation. With debris mitigation in place lifetimes of more than 1 billion pulses are estimated. For the next generation of higher power EUV LPP sources a laser driver has been tested at 1.3 kW average laser power. This will lead to 5 W EUV power in intermediate focus. The GDPP EUV sources use the Z-pinch principle with efficient sliding

  20. Concept of electric propulsion realization for high power space tug

    NASA Astrophysics Data System (ADS)

    Zakharenkov, L. E.; Semenkin, A. V.; Solodukhin, A. E.

    2016-07-01

    Popular at the beginning of the Space Age, ambitious projects aimed at Moon, Mars, and other space objects exploration, have returned with new technology and design level. High power space tug with electric propulsion system (EPS) is mainly considered as a transport vehicle for such missions. Modern high power space tugs projects as well as their spacecraft (SC) power and propulsion systems are reviewed in the paper. The main technologies and design solutions needed for high-power EPS realization are considered.

  1. High-power semiconductor separate-confinement double heterostructure lasers

    SciTech Connect

    Tarasov, I S

    2010-10-15

    The review is devoted to high-power semiconductor lasers. Historical reference is presented, physical and technological foundations are considered, and the concept of high-power semiconductor lasers is formulated. Fundamental and technological reasons limiting the optical power of a semiconductor laser are determined. The results of investigations of cw and pulsed high-power semiconductor lasers are presented. Main attention is paid to inspection of the results of experimental studies of single high-power semiconductor lasers. The review is mainly based on the data obtained in the laboratory of semiconductor luminescence and injection emitters at the A.F. Ioffe Physicotechnical Institute. (review)

  2. Progress towards high-power Li/CFx batteries: electrode architectures using carbon nanotubes with CFx.

    PubMed

    Zhang, Qing; Takeuchi, Kenneth J; Takeuchi, Esther S; Marschilok, Amy C

    2015-09-21

    Carbon monofluoride (CFx) has a high energy density, exceeding 2000 W h kg(-1), yet its application in primary lithium batteries is limited by its power capability. Multi-walled carbon nanotubes (CNTs) are appealing additives for high-power batteries, due to their outstanding electronic transport properties, high aspect ratio necessitating low volume fraction for percolation, and high tensile strength. This perspective describes the current state of the art in lithium-carbon monofluoride (Li/CFx) batteries and highlights the opportunities for the development of high-power Li/CFx batteries via utilization of carbon nanotubes. In this report, we generated several electrode architectures using CFx/CNT combinations, and demonstrated the effectiveness of CNTs in enhancing the rate capability and energy density of Li/CFx batteries. First, we investigated the resistivity of CFx combined with CNTs and compared the CFx/CNT composites with conventional carbon additives. Second, we built CFx-CNT electrodes without metallic current collectors using CNTs as substrates, and compared their electrochemical performance with conventional CFx electrodes using aluminum foil as a current collector. Furthermore, we fabricated multi-layered CNT-CFx-CNT composite electrodes (sandwich electrodes) and studied the impact of the structure on the performance of the electrode. Our work demonstrates some of the opportunities for utilization of CNTs in CFx electrodes and the resultant implementation of CFx as a battery cathode in next-generation high-power batteries.

  3. Advances in bonding technology for high power diode laser bars

    NASA Astrophysics Data System (ADS)

    Wang, Jingwei; Li, Xiaoning; Hou, Dong; Feng, Feifei; Liu, Yalong; Liu, Xingsheng

    2015-02-01

    Due to their high electrical-optical conversion efficiency, compact size and long lifetime, high power diode lasers have found increased applications in many fields. As the improvement of device technology, high power diode laser bars with output power of tens or hundreds watts have been commercially available. With the increase of high current and output power, the reliability and lifetime of high power diode laser bars becomes a challenge, especially under harsh working conditions and hard-pulse operations. The bonding technology is still one of the bottlenecks of the advancement of high power diode laser bars. Currently, materials used in bonding high power diode laser bars are commonly indium and goldtin solders. Experimental and field application results indicates that the lifetime and reliability of high power diode laser bars bonded by gold-tin solder is much better than that bonded by indium solder which is prone to thermal fatigue, electro-migration and oxidization. In this paper, we review the bonding technologies for high power diode laser bars and present the advances in bonding technology for single bars, horizontal bar arrays and vertical bar stacks. We will also present the challenges and issues in bonding technology for high power diode laser bars and discuss some approaches and strategies in addressing the challenges and issues.

  4. High power CO lasers and their application potential

    NASA Astrophysics Data System (ADS)

    Maisenhaelder, F.

    1989-06-01

    Industrial applications of high-power CO lasers are examined. The characteristics specific to CO lasers are briefly reviewed, and applications where the CO laser seems to promise wavelength-related advantages over other lasers are examined. Experimentally demonstrated applications in the drilling and cutting of metals, isotope separation and photochemistry, and laser medicine are addressed, Developments in the high power range in Japan, Soviet Union, and Germany are described, and a comparison is made between high power CO and CO2 gas lasers for civil applications.

  5. OPERATIONAL ASPECTS OF HIGH POWER ENERGY RECOVERY LINACS

    SciTech Connect

    Stephen Benson; David Douglas; Pavel Evtushenko; Kevin Jordan; George Neil; Paul Powers

    2006-08-21

    We have been operating a high-power energy-recovery linac (ERL) at Jefferson Lab for several years. In the process we have learned quite a bit about both technical and physics limitations in high power ERLs. Several groups are now considering new ERLs that greatly increase either the energy, the current or both. We will present some of our findings on what to consider when designing, building, and operating a high power ERL. Our remarks for this paper are limited to lattice design and setup, magnets, vacuum chamber design, diagnostics, and beam stability.

  6. High Power Helicon Plasma Source for Plasma Processing

    NASA Astrophysics Data System (ADS)

    Prager, James; Ziemba, Timothy; Miller, Kenneth E.

    2015-09-01

    Eagle Harbor Technologies (EHT), Inc. is developing a high power helicon plasma source. The high power nature and pulsed neutral gas make this source unique compared to traditional helicon source. These properties produce a plasma flow along the magnetic field lines, and therefore allow the source to be decoupled from the reaction chamber. Neutral gas can be injected downstream, which allows for precision control of the ion-neutral ratio at the surface of the sample. Although operated at high power, the source has demonstrated very low impurity production. This source has applications to nanoparticle productions, surface modification, and ionized physical vapor deposition.

  7. High power gas laser - Applications and future developments

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.

    1977-01-01

    Fast flow can be used to create the population inversion required for lasing action, or can be used to improve laser operation, for example by the removal of waste heat. It is pointed out that at the present time all lasers which are capable of continuous high-average power employ flow as an indispensable aspect of operation. High power laser systems are discussed, taking into account the gasdynamic laser, the HF supersonic diffusion laser, and electric discharge lasers. Aerodynamics and high power lasers are considered, giving attention to flow effects in high-power gas lasers, aerodynamic windows and beam manipulation, and the Venus machine. Applications of high-power laser technology reported are related to laser material working, the employment of the laser in controlled fusion machines, laser isotope separation and photochemistry, and laser power transmission.

  8. 8. HIGH POWER SPRAY IN MEN'S PACK ROOM. Hot ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. HIGH POWER SPRAY IN MEN'S PACK ROOM. - Hot Springs National Park Bathhouse Row, Maurice Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  9. 9. HIGH POWER SPRAY IN MEN'S STEAM ROOM. Hot ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. HIGH POWER SPRAY IN MEN'S STEAM ROOM. - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  10. Bipolar rechargeable lithium battery for high power applications

    NASA Technical Reports Server (NTRS)

    Hossain, Sohrab; Kozlowski, G.; Goebel, F.

    1993-01-01

    Viewgraphs of a discussion on bipolar rechargeable lithium battery for high power applications are presented. Topics covered include cell chemistry, electrolytes, reaction mechanisms, cycling behavior, cycle life, and cell assembly.

  11. Overview on the high power excimer laser technology

    NASA Astrophysics Data System (ADS)

    Liu, Jingru

    2013-05-01

    High power excimer laser has essential applications in the fields of high energy density physics, inertial fusion energy and industry owing to its advantages such as short wavelength, high gain, wide bandwidth, energy scalable and repetition operating ability. This overview is aimed at an introduction and evaluation of enormous endeavor of the international high power excimer laser community in the last 30 years. The main technologies of high power excimer laser are reviewed, which include the pumping source technology, angular multiplexing and pulse compressing, beam-smoothing and homogenous irradiation, high efficiency and repetitive operation et al. A high power XeCl laser system developed in NINT of China is described in detail.

  12. Developing a portable high-power microwave (HPM) prototype

    NASA Astrophysics Data System (ADS)

    Simmons, Gene

    1993-07-01

    Certain high power microwave (HPM) applications require output power in the range of only a few hundred megawatts effective radiated power (ERP) in a portable configuration. This paper describes a portable HPM device prototype that was developed, demonstrated, and evaluated.

  13. The Jefferson Lab High Power THz User Facility

    SciTech Connect

    John Klopf; Amelia Greer; Joseph Gubeli; George Neil; Michelle D. Shinn; Timothy Siggins; David W. Waldman; Gwyn Williams; Alan Todd; Vincent Christina; Oleg Chubar

    2007-04-27

    We describe here, a high power (100 Watt average, 10 MW peak) broadband THz facility based on emission from sub-picosecond bunches of relativistic electrons and the beam transport system that delivers this beam in to a user laboratory.

  14. Deposition of highly textured AlN thin films by reactive high power impulse magnetron sputtering

    SciTech Connect

    Moreira, Milena A.; Törndahl, Tobias; Katardjiev, Ilia; Kubart, Tomas

    2015-03-15

    Aluminum nitride thin films were deposited by reactive high power impulse magnetron sputtering (HiPIMS) and pulsed direct-current on Si (100) and textured Mo substrates, where the same deposition conditions were used for both techniques. The films were characterized by x-ray diffraction and atomic force microscopy. The results show a pronounced improvement in the AlN crystalline texture for all films deposited by HiPIMS on Si. Already at room temperature, the HiPIMS films exhibited a strong preferred (002) orientation and at 400 °C, no contributions from other orientations were detected. Despite the low film thickness of only 200 nm, an ω-scan full width at half maximum value of 5.1° was achieved on Si. The results are attributed to the high ionization of sputtered material achieved in HiPIMS. On textured Mo, there was no significant difference between the deposition techniques.

  15. Heterodyne Velocimetry measurements on solids shock driven by high power lasers

    NASA Astrophysics Data System (ADS)

    Mercier, Patrick; Benier, Jacky; Frugier, Pierre-Antoine; Sollier, Arnaud; Lescoute, Emilen; Cuq-Lelandais, Jean-Paul; Gay, Elise; de Resseguier, Thibaut; Berthe, Laurent; Boustie, Michel; Nivard, Mariette; Claverie, Alain; Rabec Le Gloahec, Marc

    2009-06-01

    A new Heterodyne Velocimeter (PDV) is under development at CEA for high explosive experimentations. Recently, we used it onto metallic target shock driven by high power laser. The aim is to test the ability of this means to reveal the propagation and the effects of shocks into materials, at extremely high strain rate and fast variations into the loading evolution. Spallation and fragmentation experiments carried out on aluminum samples, were performed on the LULI lasers at the Ecole Polytechnique, with both VISAR and HV diagnostics. Comparisons reveal a very good consistency of both experimental results. In addition, HV diagnostic evidence several levels of velocity in the experiment of fragmentation. Interpretation of these measurements is supported by transverse shadowgraphy analysis.

  16. Flow lasers. [fluid mechanics of high power continuous output operations

    NASA Technical Reports Server (NTRS)

    Christiansen, W. H.; Russell, D. A.; Hertzberg, A.

    1975-01-01

    The present work reviews the fluid-mechanical aspects of high-power continuous-wave (CW) lasers. The flow characteristics of these devices appear as classical fluid-mechanical phenomena recast in a complicated interactive environment. The fundamentals of high-power lasers are reviewed, followed by a discussion of the N2-CO2 gas dynamic laser. Next, the HF/DF supersonic diffusion laser is described, and finally the CO electrical-discharge laser is discussed.

  17. High power laser downhole cutting tools and systems

    SciTech Connect

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-01-20

    Downhole cutting systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser cutting operations within a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform cutting operations in such boreholes deep within the earth.

  18. Beam-path conditioning for high-power laser systems

    SciTech Connect

    Stephens, T.; Johnson, D.; Languirand, M.

    1990-01-01

    Heating of mirrors and windows by high-power radiation from a laser transmitter produces turbulent density gradients in the gas near the optical surfaces. If the gradients are left uncontrolled, the resulting phase errors reduce the intensity on the target and degrade the signal returned to a receiver. Beam path conditioning maximizes the efficiency of the optical system by alleviating thermal turbulence within the beam path. Keywords: High power radiation, Beam path, Optical surface, Laser beams, Reprints. (JHD)

  19. High power laser workover and completion tools and systems

    SciTech Connect

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2014-10-28

    Workover and completion systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser workover and completion of a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform laser workover and completion operations in such boreholes deep within the earth.

  20. Apparatus for advancing a wellbore using high power laser energy

    DOEpatents

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.

    2014-09-02

    Delivering high power laser energy to form a borehole deep into the earth using laser energy. Down hole laser tools, laser systems and laser delivery techniques for advancement, workover and completion activities. A laser bottom hole assembly (LBHA) for the delivery of high power laser energy to the surfaces of a borehole, which assembly may have laser optics, a fluid path for debris removal and a mechanical means to remove earth.

  1. High-Power, High-Temperature Superconductor Technology Development

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.

    2005-01-01

    Since the first discovery of high-temperature superconductors (HTS) 10 years ago, the most promising areas for their applications in microwave systems have been as passive components for communication systems. Soon after the discovery, experiments showed that passive microwave circuits made from HTS material exceeded the performance of conventional devices for low-power applications and could be 10 times as small or smaller. However, for superconducting microwave components, high-power microwave applications have remained elusive until now. In 1996, DuPont and Com Dev Ltd. developed high-power superconducting materials and components for communication applications under a NASA Lewis Research Center cooperative agreement, NCC3-344 "High Power High Temperature Superconductor (HTS) Technology Development." The agreement was cost shared between the Defense Advanced Research Projects Agency's (DARPA) Technology Reinvestment Program Office and the two industrial partners. It has the following objectives: 1) Material development and characterization for high-power HTS applications; 2) Development and validation of generic high-power microwave components; 3) Development of a proof-of-concept model for a high-power six-channel HTS output multiplexer.

  2. An innovative demonstration of high power density in a compact MDH (magnetohydrodynamic) generator

    NASA Astrophysics Data System (ADS)

    Schmidt, H. J.; Lineberry, J. T.; Chapman, J. N.

    1990-06-01

    The present program was conducted by the University of Tennessee Space Institute (UTSI). It was by its nature a high risk experimental program to demonstrate the feasibility of high power density operation in a laboratory scale combustion driven MHD generator. Maximization of specific energy was not a consideration for the present program, but the results have implications in this regard by virtue of high energy fuel used. The power density is the ratio of the electrical energy output to the internal volume of the generator channel. The MHD process is a volumetric process and the power density is therefore a direct measure of the compactness of the system. Specific energy, is the ratio of the electrical energy output to consumable energy used for its production. The two parameters are conceptually interrelated. To achieve high power density and implied commensurate low system volume and weight, it was necessary to use an energetic fuel. The high energy fuel of choice was a mixture of powdered aluminum and carbon seeded with potassium carbonate and burned with gaseous oxygen. The solid fuel was burned in a hybrid combustion scheme wherein the fuel was cast within a cylindrical combustor in analogy with a solid propellant rocket motor. Experimental data is limited to gross channel output current and voltage, magnetic field strength, fuel and oxidizer flow rates, flow train external temperatures and combustor pressure. Similarly, while instantaneous oxidizer flow rates were measured, only average fuel consumption based on pre and post test component weights and dimensions was possible.

  3. HIGH POWER BEAM DUMP AND TARGET / ACCELERATOR INTERFACE PROCEDURES

    SciTech Connect

    Blokland, Willem; Plum, Michael A; Peters, Charles C; Brown, David L; Galambos, John D

    2013-01-01

    Satisfying operational procedures and limits for the beam target interface is a critical concern for high power operation at spallation neutron sources. At the Oak Ridge Spallation Neutron Source (SNS) a number of protective measures are instituted to ensure that the beam position, beam size and peak intensity are within acceptable limits at the target and high power Ring Injection Dump (RID). The high power beam dump typically handles up to 50 100 kW of beam power and its setup is complicated by the fact that there are two separate beam components simultaneously directed to the dump. The beam on target is typically in the 800-1000 kW average power level, delivered in sub- s 60 Hz pulses. Setup techniques using beam measurements to quantify the beam parameters at the target and dump will be described. However, not all the instrumentation used for the setup and initial qualification is available during high power operation. Additional techniques are used to monitor the beam during high power operation to ensure the setup conditions are maintained, and these are also described.

  4. High-power slim-hole drilling system

    SciTech Connect

    Cohen, J.H.

    1995-07-01

    The objective of this project is to implement new high-power slim-hole motors and bits into field gas well drilling applications. Development of improved motors and bits is critical because rotating time constitutes the major cost of drilling gas wells. Conventional motors drill most formations 2 to 3 times faster than rotary continuous coring systems due to greater power transfer to the drill bit. New high-power motors and large-cutter TSP bits being developed by Maurer Engineering, Inc. (MEI) drill 2 to 3 times faster than conventional motors. These slim-hole high-power motors and bits, which are ready for field testing on this DOE project, should reduce drilling costs by 20 to 40 percent in many areas. The objective of Phase I is to design, manufacture and laboratory test improved high-power slim-hole motors and large-cutter TSP bits. This work will be done in preparation for Phase II field tests. The objective of Phase II will be to field test the high-power motors and bits in Amoco`s Catoosa shallow-test well near Tulsa, OK, and in deep gas wells. The goal will be to drill 2 to 3 times faster than conventional motors and to reduce the drilling costs by 20 to 40 percent over the intervals drilled.

  5. Atmospheric propagation and combining of high-power lasers.

    PubMed

    Nelson, W; Sprangle, P; Davis, C C

    2016-03-01

    In this paper, we analyze beam combining and atmospheric propagation of high-power lasers for directed-energy (DE) applications. The large linewidths inherent in high-power fiber and slab lasers cause random phase and intensity fluctuations that occur on subnanosecond time scales. Coherently combining these high-power lasers would involve instruments capable of precise phase control and operation at rates greater than ∼10  GHz. To the best of our knowledge, this technology does not currently exist. This presents a challenging problem when attempting to phase lock high-power lasers that is not encountered when phase locking low-power lasers, for example, at milliwatt power levels. Regardless, we demonstrate that even if instruments are developed that can precisely control the phase of high-power lasers, coherent combining is problematic for DE applications. The dephasing effects of atmospheric turbulence typically encountered in DE applications will degrade the coherent properties of the beam before it reaches the target. Through simulations, we find that coherent beam combining in moderate turbulence and over multikilometer propagation distances has little advantage over incoherent combining. Additionally, in cases of strong turbulence and multikilometer propagation ranges, we find nearly indistinguishable intensity profiles and virtually no difference in the energy on the target between coherently and incoherently combined laser beams. Consequently, we find that coherent beam combining at the transmitter plane is ineffective under typical atmospheric conditions.

  6. High-power MUTC photodetectors for RF photonic links

    NASA Astrophysics Data System (ADS)

    Estrella, Steven; Johansson, Leif A.; Mashanovitch, Milan L.; Beling, Andreas

    2016-02-01

    High power photodiodes are needed for a range of applications. The high available power conversion efficiency makes these ideal for antenna remoting applications, including high power, low duty-cycle RF pulse generation. The compact footprint and fiber optic input allow densely packed RF aperture arrays with low cross-talk for phased high directionality emitters. Other applications include linear RF photonic links and other high dynamic range optical systems. Freedom Photonics has developed packaged modified uni-traveling carrier (MUTC) photodetectors for high-power applications. Both single and balanced photodetector pairs are mounted on a ceramic carrier, and packaged in a compact module optimized for high power operation. Representative results include greater than 100 mA photocurrent, >100m W generated RF power and >20 GHz bandwidth. In this paper, we evaluate the saturation and bandwidth of these single ended and balanced photodetectors for detector diameter in the 16 μm to 34 μm range. Packaged performance is compared to chip performance. Further new development towards the realization of <100GHz packaged photodetector modules with optimized high power performance is described. Finally, incorporation of these photodetector structures in novel photonic integrated circuits (PICs) for high optical power application areas is outlined.

  7. Atmospheric propagation and combining of high-power lasers.

    PubMed

    Nelson, W; Sprangle, P; Davis, C C

    2016-03-01

    In this paper, we analyze beam combining and atmospheric propagation of high-power lasers for directed-energy (DE) applications. The large linewidths inherent in high-power fiber and slab lasers cause random phase and intensity fluctuations that occur on subnanosecond time scales. Coherently combining these high-power lasers would involve instruments capable of precise phase control and operation at rates greater than ∼10  GHz. To the best of our knowledge, this technology does not currently exist. This presents a challenging problem when attempting to phase lock high-power lasers that is not encountered when phase locking low-power lasers, for example, at milliwatt power levels. Regardless, we demonstrate that even if instruments are developed that can precisely control the phase of high-power lasers, coherent combining is problematic for DE applications. The dephasing effects of atmospheric turbulence typically encountered in DE applications will degrade the coherent properties of the beam before it reaches the target. Through simulations, we find that coherent beam combining in moderate turbulence and over multikilometer propagation distances has little advantage over incoherent combining. Additionally, in cases of strong turbulence and multikilometer propagation ranges, we find nearly indistinguishable intensity profiles and virtually no difference in the energy on the target between coherently and incoherently combined laser beams. Consequently, we find that coherent beam combining at the transmitter plane is ineffective under typical atmospheric conditions. PMID:26974640

  8. Design Of High Power CO2 TEA Lasers And Applications

    NASA Astrophysics Data System (ADS)

    Von Bergmann, H. M.

    2008-09-01

    There are a number of key technologies involved in the successful design and construction of high power, Carbon Dioxide TEA lasers (Transverse Excitation Atmospheric). These include uniform field electrodes, excitation circuit design including high voltage switching, discharge preionisation and for high repetition, high power applications fast transverse gas flow and the management of acoustic waves. This paper provides a summary of the design aspects of high repetition rate, high average power CO2 TEA lasers. Experimental data measured on high power CO2 TEA laser systems delivering average outputs of several kW and kHz repetition rates will be reported showing the detrimental effect of acoustic waves on laser performance and the improvement that can be achieved through effective acoustic damping measures.

  9. Stretchers and compressors for ultra-high power laser systems

    SciTech Connect

    Yakovlev, I V

    2014-05-30

    This review is concerned with pulse stretchers and compressors as key components of ultra-high power laser facilities that take advantage of chirped-pulse amplification. The potentialities, characteristics, configurations and methods for the matching and alignment of these devices are examined, with particular attention to the history of the optics of ultra-short, ultra-intense pulses before and after 1985, when the chirped-pulse amplification method was proposed, which drastically changed the view of the feasibility of creating ultra-high power laser sources. The review is intended primarily for young scientists and experts who begin to address the amplification and compression of chirped pulses, experts in laser optics and all who are interested in scientific achievements in the field of ultra-high power laser systems. (review)

  10. Klamath Falls: High-Power Acoustic Well Stimulation Technology

    SciTech Connect

    Black, Brian

    2006-07-24

    Acoustic well stimulation (AWS) technology uses high-power sonic waves from specific frequency spectra in an attempt to stimulate production in a damaged or low-production wellbore. AWS technology is one of the most promising technologies in the oil and gas industry, but it has proven difficult for the industry to develop an effective downhole prototype. This collaboration between Klamath Falls Inc. and the Rocky Mountain Oilfield Testing Center (RMOTC) included a series of tests using high-power ultrasonic tools to stimulate oil and gas production. Phase I testing was designed and implemented to verify tool functionality, power requirements, and capacity of high-power AWS tools. The purpose of Phase II testing was to validate the production response of wells with marginal production rates to AWS stimulation and to capture and identify any changes in the downhole environment after tool deployment. This final report presents methodology and results.

  11. High Power Fiber Lasers and Applications to Manufacturing

    NASA Astrophysics Data System (ADS)

    Richardson, Martin; McComb, Timothy; Sudesh, Vikas

    2008-09-01

    We summarize recent developments in high power fiber laser technologies and discuss future trends, particularly in their current and future use in manufacturing technologies. We will also describe our current research programs in fiber laser development, ultra-fast and new lasers, and will mention the expectations in these areas for the new Townes Laser Institute. It will focus on new core laser technologies and their applications in medical technologies, advanced manufacturing technologies and defense applications. We will describe a program on large mode area fiber development that includes results with the new gain-guiding approach, as well as high power infra-red fiber lasers. We will review the opportunities for high power fiber lasers in various manufacturing technologies and illustrate this with applications we are pursuing in the areas of femtosecond laser applications, advanced lithographies, and mid-IR technologies.

  12. Thermal Regime of High-power Laser Diodes

    NASA Astrophysics Data System (ADS)

    Bezotosnyi, V. V.; Krokhin, O. N.; Oleshchenko, V. A.; Pevtsov, V. F.; Popov, Yu. M.; Cheshev, E. A.

    We discuss the design and application perspectives of different crystal, ceramic and composite-type submounts with thermo-compensating properties as well as submounts from materials with high thermal conductivity for overcoming thermal problem in high-power laser diodes (LD) and improving thermal management of other high-power optoelectronic and electronic semiconductor devices. Thermal fields in high-power laser diodes were calculated in 3 D thermal model at CW operation for some heatsink designs taking into account the experimental dependence of laser total efficiency against pumping current in order to extend the range of reliable operation up to thermal loads 20-30 W and corresponding output optical power up to 15-20 W for 100 μm stripe laser diodes.

  13. Aluminum and Young Artists.

    ERIC Educational Resources Information Center

    Anderson, Thomas

    1980-01-01

    The author suggests a variety of ways in which aluminum and aluminum foil can be used in elementary and junior high art classes: relief drawing and rubbing; printing; repousse; sculpture; mobiles; foil sculpture; and three dimensional design. Sources of aluminum supplies are suggested. (SJL)

  14. Science opportunities at high power accelerators like APT

    SciTech Connect

    Browne, J.C.

    1996-12-31

    This paper presents applications of high power RF proton linear accelerators to several fields. Radioisotope production is an area in which linacs have already provided new isotopes for use in medical and industrial applications. A new type of spallation neutron source, called a long-pulse spallation source (LPSS), is discussed for application to neutron scattering and to the production and use of ultra-cold neutrons (UCN). The concept of an accelerator-driven, transmutation of nuclear waste system, based on high power RF linac technology, is presented along with its impact on spent nuclear fuels.

  15. Ultra high vacuum broad band high power microwave window

    DOEpatents

    Nguyen-Tuong, V.; Dylla, H.F. III

    1997-11-04

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost. 5 figs.

  16. Ultra high vacuum broad band high power microwave window

    DOEpatents

    Nguyen-Tuong, Viet; Dylla, III, Henry Frederick

    1997-01-01

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost.

  17. Nanosecond high-power dense microplasma switch for visible light

    SciTech Connect

    Bataller, A. Koulakis, J.; Pree, S.; Putterman, S.

    2014-12-01

    Spark discharges in high-pressure gas are known to emit a broadband spectrum during the first 10 s of nanoseconds. We present calibrated spectra of high-pressure discharges in xenon and show that the resulting plasma is optically thick. Laser transmission data show that such a body is opaque to visible light, as expected from Kirchoff's law of thermal radiation. Nanosecond framing images of the spark absorbing high-power laser light are presented. The sparks are ideal candidates for nanosecond, high-power laser switches.

  18. A portable high power microwave source with permanent magnets

    NASA Astrophysics Data System (ADS)

    Li, Wei; Zhang, Jun; Li, Zhi-qiang; Yang, Jian-Hua

    2016-06-01

    A high power microwave source with permanent magnets is proposed in this paper. The source has the length 330 mm, maximum diameter 350 mm, and total weight 50 kg, including 25 kg of permanent magnets. 1 GW of microwave power with Gaussian radiation pattern and 24% of microwave power generation efficiency in a pulse duration of 75 ns are obtained in the experiment. Operating frequency of the source is 2.32 GHz. Such a small size, light weight, and highly stable in operation source will be used in portable repetitive high power microwave generation systems.

  19. Nanosecond high-power dense microplasma switch for visible light

    NASA Astrophysics Data System (ADS)

    Bataller, A.; Koulakis, J.; Pree, S.; Putterman, S.

    2014-12-01

    Spark discharges in high-pressure gas are known to emit a broadband spectrum during the first 10 s of nanoseconds. We present calibrated spectra of high-pressure discharges in xenon and show that the resulting plasma is optically thick. Laser transmission data show that such a body is opaque to visible light, as expected from Kirchoff's law of thermal radiation. Nanosecond framing images of the spark absorbing high-power laser light are presented. The sparks are ideal candidates for nanosecond, high-power laser switches.

  20. The High Power Electric Propulsion (HiPEP) Ion Thruster

    NASA Technical Reports Server (NTRS)

    Foster, John E.; Haag, Tom; Patterson, Michael; Williams, George J., Jr.; Sovey, James S.; Carpenter, Christian; Kamhawi, Hani; Malone, Shane; Elliot, Fred

    2004-01-01

    Practical implementation of the proposed Jupiter Icy Moon Orbiter (JIMO) mission, which would require a total delta V of approximately 38 km/s, will require the development of a high power, high specific impulse propulsion system. Initial analyses show that high power gridded ion thrusters could satisfy JIMO mission requirements. A NASA GRC-led team is developing a large area, high specific impulse, nominally 25 kW ion thruster to satisfy both the performance and the lifetime requirements for this proposed mission. The design philosophy and development status as well as a thruster performance assessment are presented.

  1. Aluminum reference electrode

    DOEpatents

    Sadoway, Donald R.

    1988-01-01

    A stable reference electrode for use in monitoring and controlling the process of electrolytic reduction of a metal. In the case of Hall cell reduction of aluminum, the reference electrode comprises a pool of molten aluminum and a solution of molten cryolite, Na.sub.3 AlF.sub.6, wherein the electrical connection to the molten aluminum does not contact the highly corrosive molten salt solution. This is accomplished by altering the density of either the aluminum (decreasing the density) or the electrolyte (increasing the density) so that the aluminum floats on top of the molten salt solution.

  2. Aluminum reference electrode

    DOEpatents

    Sadoway, D.R.

    1988-08-16

    A stable reference electrode is described for use in monitoring and controlling the process of electrolytic reduction of a metal. In the case of Hall cell reduction of aluminum, the reference electrode comprises a pool of molten aluminum and a solution of molten cryolite, Na[sub 3]AlF[sub 6], wherein the electrical connection to the molten aluminum does not contact the highly corrosive molten salt solution. This is accomplished by altering the density of either the aluminum (decreasing the density) or the electrolyte (increasing the density) so that the aluminum floats on top of the molten salt solution. 1 fig.

  3. High-power lasers for directed-energy applications.

    PubMed

    Sprangle, Phillip; Hafizi, Bahman; Ting, Antonio; Fischer, Richard

    2015-11-01

    In this article, we review and discuss the research programs at the Naval Research Laboratory (NRL) on high-power lasers for directed-energy (DE) applications in the atmosphere. Physical processes affecting propagation include absorption/scattering, turbulence, and thermal blooming. The power levels needed for DE applications require combining a number of lasers. In atmospheric turbulence, there is a maximum intensity that can be placed on a target that is independent of the initial beam spot size and laser beam quality. By combining a number of kW-class fiber lasers, scientists at the NRL have successfully demonstrated high-power laser propagation in a turbulent atmosphere and wireless recharging. In the NRL experiments, four incoherently combined fiber lasers having a total power of 5 kW were propagated to a target 3.2 km away. These successful high-power experiments in a realistic atmosphere formed the basis of the Navy's Laser Weapon System. We compare the propagation characteristics of coherently and incoherently combined beams without adaptive optics. There is little difference in the energy on target between coherently and incoherently combined laser beams for multi-km propagation ranges and moderate to high levels of turbulence. Unlike incoherent combining, coherent combining places severe constraints on the individual lasers. These include the requirement of narrow power spectral linewidths in order to have long coherence times as well as polarization alignment of all the lasers. These requirements are extremely difficult for high-power lasers. PMID:26560609

  4. Device for wavefront correction in an ultra high power laser

    DOEpatents

    Ault, Earl R.; Comaskey, Brian J.; Kuklo, Thomas C.

    2002-01-01

    A system for wavefront correction in an ultra high power laser. As the laser medium flows past the optical excitation source and the fluid warms its index of refraction changes creating an optical wedge. A system is provided for correcting the thermally induced optical phase errors.

  5. High Power Electric Propulsion for Deep Space Missions

    NASA Technical Reports Server (NTRS)

    Polk, Jay

    2011-01-01

    Slide presentation reviews: (1) An Electric Propulsion Primer (2) The Flexible Path and the Electric Path (2a) A New Plan for Human Exploration (2b)The Role of Electric Propulsion (3) High Power Electric Thrusters (3a)Hall Thrusters (3b) Magnetoplasmadynamic Thrusters (4)Challenges for the Next Generation of Advanced Propulsion Technologist

  6. Target R and D for high power proton beam applications

    SciTech Connect

    Fabich, A.

    2008-02-21

    High power targets are one of the major issues in an accelerator complex for future HEP physic studies. The paper will review status of studies worldwide. It will focus on the status of the MERIT mercury-jet target experiment at CERN.

  7. Observations of clear air turbulence by high power radar.

    PubMed

    Browning, K A; Watkins, C D

    1970-07-18

    Clear air turbulence is a hazard to aviation and is thought to have important effects on atmospheric dynamics. This article describes the structure and evolution of clear air turbulence at high altitudes as revealed by a high power radar and vertical soundings of wind and temperature.

  8. High-power, high-intensity laser propagation and interactions

    SciTech Connect

    Sprangle, Phillip; Hafizi, Bahman

    2014-05-15

    This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

  9. High-power lasers for directed-energy applications.

    PubMed

    Sprangle, Phillip; Hafizi, Bahman; Ting, Antonio; Fischer, Richard

    2015-11-01

    In this article, we review and discuss the research programs at the Naval Research Laboratory (NRL) on high-power lasers for directed-energy (DE) applications in the atmosphere. Physical processes affecting propagation include absorption/scattering, turbulence, and thermal blooming. The power levels needed for DE applications require combining a number of lasers. In atmospheric turbulence, there is a maximum intensity that can be placed on a target that is independent of the initial beam spot size and laser beam quality. By combining a number of kW-class fiber lasers, scientists at the NRL have successfully demonstrated high-power laser propagation in a turbulent atmosphere and wireless recharging. In the NRL experiments, four incoherently combined fiber lasers having a total power of 5 kW were propagated to a target 3.2 km away. These successful high-power experiments in a realistic atmosphere formed the basis of the Navy's Laser Weapon System. We compare the propagation characteristics of coherently and incoherently combined beams without adaptive optics. There is little difference in the energy on target between coherently and incoherently combined laser beams for multi-km propagation ranges and moderate to high levels of turbulence. Unlike incoherent combining, coherent combining places severe constraints on the individual lasers. These include the requirement of narrow power spectral linewidths in order to have long coherence times as well as polarization alignment of all the lasers. These requirements are extremely difficult for high-power lasers.

  10. In-volume heating using high-power laser diodes

    NASA Astrophysics Data System (ADS)

    Denisenkov, Valentin S.; Kiyko, Vadim V.; Vdovin, Gleb V.

    2015-03-01

    High-power lasers are useful instruments suitable for applications in various fields; the most common industrial applications include cutting and welding. We propose a new application of high-power laser diodes as in-bulk heating source for food industry. Current heating processes use surface heating with different approaches to make the heat distribution more uniform and the process more efficient. High-power lasers can in theory provide in-bulk heating which can sufficiently increase the uniformity of heat distribution thus making the process more efficient. We chose two media (vegetable fat and glucose) for feasibility experiments. First, we checked if the media have necessary absorption coefficients on the wavelengths of commercially available laser diodes (940-980 nm). This was done using spectrophotometer at 700-1100 nm which provided the dependences of transmission from the wavelength. The results indicate that vegetable fat has noticeable transmission dip around 925 nm and glucose has sufficient dip at 990 nm. Then, after the feasibility check, we did numerical simulation of the heat distribution in bulk using finite elements method. Based on the results, optimal laser wavelength and illuminator configuration were selected. Finally, we carried out several pilot experiments with high-power diodes heating the chosen media.

  11. Overview of the NASA high power laser program

    NASA Technical Reports Server (NTRS)

    Lundholm, J. G.

    1976-01-01

    The overall objectives of the NASA High Power Laser Program are reviewed along with their structure and center responsibilities. Present and future funding, laser power transmission in space, selected program highlights, the research and technology schedule, and the expected pace of the program are briefly considered.

  12. The anisotropy of aluminum and aluminum alloys

    NASA Astrophysics Data System (ADS)

    Hosford, William F.

    2006-05-01

    The anisotropy of textured aluminum is approximated by a yield criterion with an exponent of eight. The use of this criterion in metal-forming analyses has improved the understanding of the formability of aluminum and other metals. The effect of anisotropy on the limiting drawing ratio in cupping is less than that expected from the quadratic Hill yield criterion and the effect of texture on forming limit diagrams is negligible. A method of predicting the effect of strain-path changes on forming limit curves of aluminum alloy sheets has proven to agree with experiments.

  13. Thick film fabrication of aluminum nitride microcircuits. Final report

    SciTech Connect

    Perdieu, L.H.

    1994-03-01

    A new substrate material, aluminum nitride (AlN), and 11 new thick film inks were analyzed to determine their chemical compatibility, their electrical properties, their mechanical properties, and their overall suitability for use in the manufacturing of high-power microcircuits with efficient thermal properties. Because high-power chips emit a great deal of heat in a small surface area, a new substrate material was needed to dissipate that heat faster than the substrate material currently in use. Overall, the new materials were found to be acceptable for accomplishing this purpose.

  14. Transient Plasma Photonic Crystals for High-Power Lasers.

    PubMed

    Lehmann, G; Spatschek, K H

    2016-06-01

    A new type of transient photonic crystals for high-power lasers is presented. The crystal is produced by counterpropagating laser beams in plasma. Trapped electrons and electrically forced ions generate a strong density grating. The lifetime of the transient photonic crystal is determined by the ballistic motion of ions. The robustness of the photonic crystal allows one to manipulate high-intensity laser pulses. The scheme of the crystal is analyzed here by 1D Vlasov simulations. Reflection or transmission of high-power laser pulses are predicted by particle-in-cell simulations. It is shown that a transient plasma photonic crystal may act as a tunable mirror for intense laser pulses. Generalizations to 2D and 3D configurations are possible. PMID:27314721

  15. Test Results From a High Power Linear Alternator Test Rig

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur G.; Hervol, David S.; Gardner, Brent G.

    2010-01-01

    Stirling cycle power conversion is an enabling technology that provides high thermodynamic efficiency but also presents unique challenges with regard to electrical power generation, management, and distribution. The High Power Linear Alternator Test Rig (HPLATR) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio is a demonstration test bed that simulates electrical power generation from a Stirling engine driven alternator. It implements the high power electronics necessary to provide a well regulated DC user load bus. These power electronics use a novel design solution that includes active rectification and power factor control, active ripple suppression, along with a unique building block approach that permits the use of high voltage or high current alternator designs. This report describes the HPLATR, the test program, and the operational results.

  16. Test Results from a High Power Linear Alternator Test Rig

    NASA Technical Reports Server (NTRS)

    Birchenough, Arthur G.; Hervol, David S.; Gardner, Brent G.

    2010-01-01

    Stirling cycle power conversion is an enabling technology that provides high thermodynamic efficiency but also presents unique challenges with regard to electrical power generation, management, and distribution. The High Power Linear Alternator Test Rig (HPLATR) located at the NASA Glenn Research Center (GRC) in Cleveland, OH is a demonstration test bed that simulates electrical power generation from a Stirling engine driven alternator. It implements the high power electronics necessary to provide a well regulated DC user load bus. These power electronics use a novel design solution that includes active rectification and power factor control, active ripple suppression, along with a unique building block approach that permits the use of high voltage or high current alternator designs. This presentation describes the HPLATR, the test program, and the operational results.

  17. Designing high power targets with computational fluid dynamics (CFD)

    SciTech Connect

    Covrig, S. D.

    2013-11-07

    High power liquid hydrogen (LH2) targets, up to 850 W, have been widely used at Jefferson Lab for the 6 GeV physics program. The typical luminosity loss of a 20 cm long LH2 target was 20% for a beam current of 100 μA rastered on a square of side 2 mm on the target. The 35 cm long, 2500 W LH2 target for the Qweak experiment had a luminosity loss of 0.8% at 180 μA beam rastered on a square of side 4 mm at the target. The Qweak target was the highest power liquid hydrogen target in the world and with the lowest noise figure. The Qweak target was the first one designed with CFD at Jefferson Lab. A CFD facility is being established at Jefferson Lab to design, build and test a new generation of low noise high power targets.

  18. Designing high power targets with computational fluid dynamics (CFD)

    SciTech Connect

    Covrig, Silviu D.

    2013-11-01

    High power liquid hydrogen (LH2) targets, up to 850 W, have been widely used at Jefferson Lab for the 6 GeV physics program. The typical luminosity loss of a 20 cm long LH2 target was 20% for a beam current of 100 {micro}A rastered on a square of side 2 mm on the target. The 35 cm long, 2500 W LH2 target for the Qweak experiment had a luminosity loss of 0.8% at 180 {micro}A beam rastered on a square of side 4 mm at the target. The Qweak target was the highest power liquid hydrogen target in the world and with the lowest noise figure. The Qweak target was the first one designed with CFD at Jefferson Lab. A CFD facility is being established at Jefferson Lab to design, build and test a new generation of low noise high power targets.

  19. SPALLATION NEUTRON SOURCE HIGH-POWER PROTECTION MODULE TEST STAND

    SciTech Connect

    Lee, Sung-Woo; Ball, Jeffrey Allen; Crofford, Mark T; Davidson Jr, Taylor L; Jones, Stacey L; Hardek, Thomas W

    2010-01-01

    The Spallation Neutron Source (SNS) High-Power Protection Module (HPM) provides interlocks and fast shutdown for the radio frequency (RF) system to protect the accelerating structures and high power RF (HPRF) Distribution System. The HPM has required some functional upgrades since the start of beam operations and an upgrade to the HPM test stand was required to support these added features. The HPM test stand currently verifies functionality, RF channel calibration, and measurement of the speed of shutdown to ensure the specifications are met. The upgraded test stand was implemented in a Field Programmable Gate Array (FPGA) to allow for future growth and flexibility. Work is currently progressing on automation of the test stand to better perform the required module calibration schedule.

  20. High-power slim-hole drilling system

    SciTech Connect

    Cohen, J.H.; Maurer, W.C.; Leitko, C.E.

    1995-12-31

    Economic conditions in the oil and gas industry have encouraged the use of new methods to reduce drilling costs. Slim-hole drilling, abandoned in the past, has found new life because it offers savings by reducing equipment size, tubular products, and environmental impact. A new high-power slim-hole drilling system has been developed that overcomes many of the problems that led to the abandonment of slim holes in the past. This new system is composed of a new high-power positive-displacement motor and new TSP bits developed to run at high horsepowers and produce high drilling rates, The new slim-hole system has the potential for reducing drilling costs by 40 to 60 percent.

  1. High Power Laser Hybrid Welding - Challenges and Perspectives

    NASA Astrophysics Data System (ADS)

    Nielsen, Steen Erik

    High power industrial lasers at power levels up to 100 kW is now available on the market. Therefore, welding of thicker materials has become of interest for the heavy metal industry e.g. shipyards and wind mill producers. Further, the power plant industry, producers of steel pipes, heavy machinery and steel producers are following this new technology with great interest. At Lindø Welding Technology (LWT), which is a subsidiary to FORCE Technology, a 32-kwatt disc laser is installed. At this laser facility, welding procedures related to thick section steel applications are developed. Material thicknesses between 40 and 100 mm are currently of interest. This paper describes some of the challenges that are related to the development of the high power hybrid laser welding process as well as to the perspectives for the technology as a production tool for the heavy metal industry.

  2. Inductance effects in the high-power transmitter crowbar system

    NASA Technical Reports Server (NTRS)

    Daeges, J.; Bhanji, A.

    1987-01-01

    The effective protection of a klystron in a high-power transmitter requires the diversion of all stored energy in the protected circuit through an alternate low-impedance path, the crowbar, such that less than 1 joule of energy is dumped into the klystron during an internal arc. A scheme of adding a bypass inductor in the crowbar-protected circuit of the high-power transmitter was tested using computer simulations and actual measurements under a test load. Although this scheme has several benefits, including less power dissipation in the resistor, the tests show that the presence of inductance in the portion of the circuit to be protected severely hampers effective crowbar operation.

  3. High power microwave components for space communications satellite

    NASA Technical Reports Server (NTRS)

    Jankowski, H.; Geia, A.

    1972-01-01

    Analyzed, developed, and tested were high power microwave components for communications satellites systems. Included were waveguide and flange configurations with venting, a harmonic filter, forward and reverse power monitors, electrical fault sensors, and a diplexer for two channel simultaneous transmission. The assembly of 8.36 GHz components was bench tested, and then operated for 60 hours at 3.5 kW CW in a high vacuum. The diplexer was omitted from this test pending a modification of its end irises. An RF leakage test showed only that care is required at flange junctions; all other components were RF tight. Designs were extrapolated for 12 GHz and 2.64 GHz high power satellite systems.

  4. HIGH POWER OPERATIONS AT THE LOW ENERGY DEMONSTRATION ACCELERATOR (LEDA)

    SciTech Connect

    M. DURAN; V. R. HARRIS

    2001-01-01

    Recently, the Low-Energy Demonstration Accelerator (LEDA) portion of the Accelerator Production of Tritium (APT) project reached its 100-mA, 8-hr continuous wave (CW) beam operation milestone. The LEDA accelerator is a prototype of the low-energy front-end of the linear accelerator (linac) that would have been used in an APT plant. LEDA consists of a 75-keV proton injector, 6.7-MeV, 350-MHz CW radio-frequency quadrupole (RFQ) with associated high-power and low-level RF systems, a short high-energy beam transport (HEBT) and high-power (670-kW CW) beam dump. Details of the LEDA design features will be discussed along with the operational health physics experiences that occurred during the LEDA commissioning phase.

  5. Photoconductive switching for HPM (high power microwave) generation

    SciTech Connect

    Pocha, M.D.; Hofer, W.W.

    1990-01-01

    Photoconductive switching has been explored at LLNL and demonstrated to be a viable technology for high power microwave (HPM) generation. This technology enables the development of compact, portable, and efficient HPM sources. At LLNL we have successfully switched 35 KV in <200 ps using laser triggered, 1 {times} 5 {times} 20 mm GaAs switches. Based on these results we are developing an HPM generator with applications for HPM weapons and high power, wideband radar. The paper will discuss the physics limits and tradeoffs in the application of this technology. Among the topics discussed will be switching efficiency, candidate switch materials, laser requirements, applicable laser technologies, generator configurations, and cooling requirements and techniques. In addition to presenting theoretical and practical considerations, the paper will discuss on-going work at LLNL and elsewhere. 11 refs., 2 figs., 1 tab.

  6. High-Power Ka-Band Window and Resonant Ring

    SciTech Connect

    Jay L. Hirshfield

    2006-11-29

    A stand-alone 200 MW rf test station is needed for carrying out development of accelerator structures and components for a future high-gradient multi-TeV collider, such as CLIC. A high-power rf window is needed to isolate the test station from a structure element under test. This project aimed to develop such a window for use at a frequency in the range 30-35 GHz, and to also develop a high-power resonant ring for testing the window. During Phase I, successful conceptual designs were completed for the window and the resonant ring, and cold tests of each were carried out that confirmed the designs.

  7. High-power laser chains used for laser isotope separation

    NASA Astrophysics Data System (ADS)

    Lompre, Louis A.

    2000-01-01

    Since 1985, France has chosen to focus on the selective photo-ionization process called SILVA for uranium enrichment. The general SILVA schedule has led to the construction of a pilot facility called ASTER, aimed to a general assessment of SILVA. It utilizes a mid power dye laser chain pumped by copper vapor laser chains. An alternative solution to pump dye laser is under development. It is based on high-power diode-pumped frequency doubled Nd:YAG modules. Performances as high as 150 Watts, at 532 nm, 10 kHz and pulse duration shorter than 75 ns have been obtained. The electrical efficiency overpasses 5 percent. The paper will give a description of the high power laser chains used or proposed for laser isotope separation.

  8. Transient Plasma Photonic Crystals for High-Power Lasers

    NASA Astrophysics Data System (ADS)

    Lehmann, G.; Spatschek, K. H.

    2016-06-01

    A new type of transient photonic crystals for high-power lasers is presented. The crystal is produced by counterpropagating laser beams in plasma. Trapped electrons and electrically forced ions generate a strong density grating. The lifetime of the transient photonic crystal is determined by the ballistic motion of ions. The robustness of the photonic crystal allows one to manipulate high-intensity laser pulses. The scheme of the crystal is analyzed here by 1D Vlasov simulations. Reflection or transmission of high-power laser pulses are predicted by particle-in-cell simulations. It is shown that a transient plasma photonic crystal may act as a tunable mirror for intense laser pulses. Generalizations to 2D and 3D configurations are possible.

  9. High power l-band fast phase shifter

    SciTech Connect

    Terechkine, I.; Khabiboulline, T.; Solyak, N.; /Fermilab

    2008-10-01

    Following successful testing of a concept prototype of a waveguide-based high power phase shifter, a design of a fast, high power device has been developed. The shifter uses two magnetically biased blocks of Yttrium Iron Garnet (YIG) positioned along the side walls of a rectangular waveguide. The cross-section of the waveguide is chosen to suppress unwanted RF modes that could otherwise compromise performance of the phase shifter. Static bias field in the YIG blocks is created by employing permanent magnets. Low inductance coils in the same magnetic circuit excite fast component of the bias field. Design of the device ensures effective heat extraction from the YIG blocks and penetration of the fast magnetic field inside the waveguide with minimum delay. This paper summarizes main steps in this development and gives brief description of the system.

  10. Gate Drive For High Speed, High Power IGBTs

    SciTech Connect

    Nguyen, M.N.; Cassel, R.L.; de Lamare, J.E.; Pappas, G.C.; /SLAC

    2007-06-18

    A new gate drive for high-voltage, high-power IGBTs has been developed for the SLAC NLC (Next Linear Collider) Solid State Induction Modulator. This paper describes the design and implementation of a driver that allows an IGBT module rated at 800A/3300V to switch up to 3000A at 2200V in 3{micro}S with a rate of current rise of more than 10000A/{micro}S, while still being short circuit protected. Issues regarding fast turn on, high de-saturation voltage detection, and low short circuit peak current will be presented. A novel approach is also used to counter the effect of unequal current sharing between parallel chips inside most high-power IGBT modules. It effectively reduces the collector-emitter peak current, and thus protects the IGBT from being destroyed during soft short circuit conditions at high di/dt.

  11. High power continuous-wave Alexandrite laser with green pump

    NASA Astrophysics Data System (ADS)

    Ghanbari, Shirin; Major, Arkady

    2016-07-01

    We report on a continuous-wave (CW) Alexandrite (Cr:BeAl2O4) laser, pumped by a high power green source at 532 nm with a diffraction limited beam. An output power of 2.6 W at 755 nm, a slope efficiency of 26%, and wavelength tunability of 85 nm have been achieved using 11 W of green pump. To the best of our knowledge, this is the highest CW output power of a high brightness laser pumped Alexandrite laser reported to date. The results obtained in this experiment can lead to the development of a high power tunable CW and ultrafast sources of the near-infrared or ultraviolet radiation through frequency conversion.

  12. High-Power Microwave Transmission and Mode Conversion Program

    SciTech Connect

    Vernon, Ronald J.

    2015-08-14

    This is a final technical report for a long term project to develop improved designs and design tools for the microwave hardware and components associated with the DOE Plasma Fusion Program. We have developed basic theory, software, fabrication techniques, and low-power measurement techniques for the design of microwave hardware associated gyrotrons, microwave mode converters and high-power microwave transmission lines. Specifically, in this report we discuss our work on designing quasi-optical mode converters for single and multiple frequencies, a new method for the analysis of perturbed-wall waveguide mode converters, perturbed-wall launcher design for TE0n mode gyrotrons, quasi-optical traveling-wave resonator design for high-power testing of microwave components, and possible improvements to the HSX microwave transmission line.

  13. A Lemon Cell Battery for High-Power Applications

    NASA Astrophysics Data System (ADS)

    Muske, Kenneth R.; Nigh, Christopher W.; Weinstein, Randy D.

    2007-04-01

    This article discusses the development of a lemon cell battery for high-power applications. The target application is the power source of a dc electric motor for a model car constructed by first-year engineering students as part of their introductory course design project and competition. The battery is composed of a series of lemon juice cells made from UV vis cuvets that use a magnesium anode and copper cathode. Dilution of the lemon juice to reduce the rate of corrosion of the magnesium anode and the addition of table salt to reduce the internal resistance of the cell are examined. Although our specific interest is the use of this lemon cell battery to run an electric dc motor, high-power applications such as radios, portable cassette or CD players, and other battery-powered toys are equally appropriate for demonstration and laboratory purposes using this battery.

  14. Aspects of aluminum toxicity

    SciTech Connect

    Hewitt, C.D.; Savory, J.; Wills, M.R. )

    1990-06-01

    Aluminum is the most abundant metal in the earth's crust. The widespread occurrence of aluminum, both in the environment and in foodstuffs, makes it virtually impossible for man to avoid exposure to this metal ion. Attention was first drawn to the potential role of aluminum as a toxic metal over 50 years ago, but was dismissed as a toxic agent as recently as 15 years ago. The accumulation of aluminum, in some patients with chronic renal failure, is associated with the development of toxic phenomena; dialysis encephalopathy, osteomalacic dialysis osteodystrophy, and an anemia. Aluminum accumulation also occurs in patients who are not on dialysis, predominantly infants and children with immature or impaired renal function. Aluminum has also been implicated as a toxic agent in the etiology of Alzheimer's disease, Guamiam amyotrophic lateral sclerosis, and parkinsonism-dementia. 119 references.

  15. An innovative demonstration of high power density in a compact MHD (magnetohydrodynamic) generator

    SciTech Connect

    Schmidt, H.J.; Lineberry, J.T.; Chapman, J.N.

    1990-06-01

    The present program was conducted by the University of Tennessee Space Institute (UTSI). It was by its nature a high risk experimental program to demonstrate the feasibility of high power density operation in a laboratory scale combustion driven MHD generator. Maximization of specific energy was not a consideration for the present program, but the results have implications in this regard by virtue of high energy fuel used. The power density is the ratio of the electrical energy output to the internal volume of the generator channel. The MHD process is a volumetric process and the power density is therefore a direct measure of the compactness of the system. Specific energy, is the ratio of the electrical energy output to consumable energy used for its production. The two parameters are conceptually interrelated. To achieve high power density and implied commensurate low system volume and weight, it was necessary to use an energetic fuel. The high energy fuel of choice was a mixture of powdered aluminum and carbon seeded with potassium carbonate and burned with gaseous oxygen. The solid fuel was burned in a hybrid combustion scheme wherein the fuel was cast within a cylindrical combustor in analogy with a solid propellant rocket motor. Experimental data is limited to gross channel output current and voltage, magnetic field strength, fuel and oxidizer flow rates, flow train external temperatures and combustor pressure. Similarly, while instantaneous oxidizer flow rates were measured, only average fuel consumption based on pre and post test component weights and dimensions was possible. 4 refs., 60 figs., 9 tabs.

  16. Optical design of a high power fiber optic coupler

    SciTech Connect

    English, R.E. Jr.; Halpin, J.M.; House, F.A.; Paris, R.D.

    1991-06-19

    Fiber optic beam delivery systems are replacing conventional mirror delivery systems for many reasons (e.g., system flexibility and redundancy, stability, and ease of alignment). Commercial products are available that use of fiber optic delivery for laser surgery and materials processing. Also, pump light of dye lasers can be delivered by optical fibers. Many laser wavelengths have been transported via optical fibers; high power delivery has been reported for argon, Nd:YAG, and excimer. We have been developing fiber optic beam delivery systems for copper vapor laser light; many of the fundamental properties of these systems are applicable to other high power delivery applications. A key element of fiber optic beam delivery systems is the coupling of laser light into the optical fiber. For our application this optical coupler must be robust to a range of operating parameters and laser characteristics. We have access to a high power copper vapor laser beam that is generated by a master oscillator/power amplifier (MOPA) chain comprised of three amplifiers. The light has a pulse width of 40--50 nsec with a repetition rate of about 4 kHz. The average power (nominal) to be injected into a fiber is 200 W. (We will refer to average power in this paper.) In practice, the laser beam's direction and collimation change with time. These characteristics plus other mechanical and operational constraints make it difficult for our coupler to be opto-mechanically referenced to the laser beam. We describe specifications, design, and operation of an optical system that couples a high-power copper vapor laser beam into a large core, multimode fiber. The approach used and observations reported are applicable to fiber optic delivery applications. 6 refs., 6 figs.

  17. High-power laser diodes at various wavelengths

    SciTech Connect

    Emanuel, M.A.

    1997-02-19

    High power laser diodes at various wavelengths are described. First, performance and reliability of an optimized large transverse mode diode structure at 808 and 941 nm are presented. Next, data are presented on a 9.5 kW peak power array at 900 nm having a narrow emission bandwidth suitable for pumping Yb:S-FAP laser materials. Finally, results on a fiber-coupled laser diode array at {approx}730 nm are presented.

  18. Method and apparatus for improved high power impulse magnetron sputtering

    DOEpatents

    Anders, Andre

    2013-11-05

    A high power impulse magnetron sputtering apparatus and method using a vacuum chamber with a magnetron target and a substrate positioned in the vacuum chamber. A field coil being positioned between the magnetron target and substrate, and a pulsed power supply and/or a coil bias power supply connected to the field coil. The pulsed power supply connected to the field coil, and the pulsed power supply outputting power pulse widths of greater that 100 .mu.s.

  19. High power millimeter and submillimeter wave lasers and gyrotrons

    NASA Astrophysics Data System (ADS)

    Temkin, R. J.; Cohn, D. R.; Danly, B. G.; Kreischer, K. E.; Woskoboinikow, P.

    1985-10-01

    High power sources of coherent radiation in the millimeter and submillimeter wavelength range are useful in a number of applications, including plasma heating, plasma diagnostics, radar and communications. Two of the most important sources in this wavelength range are the optically pumped laser and the gyrotron. Major recent advances in both laser and gyrotron research are described. Possible techniques for improving the efficiency and operating characteristics of these devices are also reviewed.

  20. High power operational experience with the LANSCE Linac

    SciTech Connect

    Rybarcyk, Lawrence J

    2008-01-01

    The heart of the Los Alamos Neutron Science Center (LANSCE) is a pulsed linear accelerator that is used to simultaneously provide H+ and H- beams to several user facilities. This accelerator contains two Cockcroft-Walton style injectors, a 100-MeV drift tube linac and an 800-MeV coupled cavity linac. This presentation will touch on various aspects of the high power operation including performance, tune-up strategy, beam losses and machine protection.