Sample records for high-power aluminum z-pinch

  1. Time-dependent electron temperature diagnostics for high-power aluminum z-pinch plasmas

    SciTech Connect

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

    1996-08-01

    Time-resolved x-ray pinhole photographs and time-integrated radially-resolved x-ray crystal-spectrometer measurements of azimuthally-symmetric aluminum-wire implosions suggest that the densest phase of the pinch is composed of a hot plasma core surrounded by a cooler plasma halo. The slope of the free-bound x-ray continuum, provides a time-resolved, model-independent diagnostic of the core electron temperature. A simultaneous measurement of the time-resolved K-shell line spectra provides the electron temperature of the spatially averaged plasma. Together, the two diagnostics support a 1-D Radiation-Hydrodynamic model prediction of a plasma whose thermalization on axis produces steep radial gradients in temperature, from temperatures in excess of a kilovolt in the core to below a kilovolt in the surrounding plasma halo.

  2. Experimental astrophysics with high power lasers and Z pinches

    SciTech Connect

    Remington, Bruce A.; Drake, R. Paul; Ryutov, Dmitri D. [Lawrence Livermore National Laboratory, Livermore, California 94450 (United States); University of Michigan, Ann Arbor, Michigan 48109 (United States); Lawrence Livermore National Laboratory, Livermore, California 94450 (United States)

    2006-07-15

    With the advent of high-energy-density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, millimeter-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.

  3. 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.

  4. Structure of stagnated plasma in aluminum wire array Z pinches

    SciTech Connect

    Hall, G. N.; Pikuz, S. A.; Shelkovenko, T. A.; Bland, S. N.; Lebedev, S. V.; Ampleford, D. J.; Palmer, J. B. A.; Bott, S. C.; Rapley, J.; Chittenden, J. P.; Apruzese, J. P. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States); Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2006-08-15

    Experiments with aluminum wire array Z pinches have been carried out on the mega-ampere generator for plasma implosion experiments (MAGPIE) at Imperial College London [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (1996)]. It has been shown that in these arrays, there are two intense sources of radiation during stagnation; Al XII line emission from a precursor-sized object, and both continuum and Al XIII radiation from bright spots of either significantly higher temperature or density randomly distributed around this object so as to produce a hollow emission profile. Spatially resolved spectra produced by spherically bent crystals were recorded, both time-integrated and time-resolved, and were used to show that these two sources of radiation peak at the same time.

  5. Optimization of K-shell emission in aluminum z-pinch implosions: Theory versus experiment

    Microsoft Academic Search

    K. G. Whitney; J. W. Thornhill; J. L. Jr. Giuliani; J. Davis; L. A. Miles; E. E. Nolting; V. L. Kenyon; W. A. Speicer; J. A. Draper; C. R. Parsons; P. Dang; R. B. Spielman; T. J. Nash; J. S. McGurn; L. E. Ruggles; C. Deeney; R. R. Prasad; L. Warren

    1994-01-01

    Two sets of z-pinch experiments were recently completed at the Saturn and Phoenix facilities of Sandia National Laboratories and the Naval Surface Warfare Center, respectively, using aluminum wire arrays of different wire and array diameters. Measurements of the total x-ray yield from the K shell of aluminum were made. In this paper, a comparison of these measurements is made to

  6. Implosion of an aluminum plasma jet onto a coaxial wire: A Z pinch with enhanced stability and energy transfer

    Microsoft Academic Search

    F. J. Wessel; B. Etlicher; P. Choi

    1992-01-01

    We describe Z-pinch experiments imploding an aluminum-plasma jet onto a coaxial, micron-diameter wire. Spatially resolved x-ray pinhole images and time resolved x-ray data indicate that energy is supplied initially to the aluminum-jet plasma and subsequently transferred to the wire. The resultant pinch appears more uniform (stable) than a wire-only or jet-only pinch and demonstrates that an imploding-plasma liner will couple

  7. Analyzing time-resolved spectroscopic data from an azimuthally symmetric, aluminum-wire array, z-pinch implosion

    Microsoft Academic Search

    K. G. Whitney; J. W. Thornhill; P. E. Pulsifer; J. P. Apruzese; T. W. Sanford; T. J. Nash; R. C. Mock; R. B. Spielman

    1997-01-01

    A 90-wire, aluminum, z-pinch experiment was conducted on the Saturn accelerator at the Sandia National Laboratories that exhibited azimuthally symmetric implosions and two x-ray bursts, a main burst and a subsidiary one. These bursts correlated with two consecutive radial implosions and are consistent with predicted magnetohydrodynamics behavior. A variety of time-resolved, accurately timed, spectroscopic measurements were made in this experiment

  8. 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). PMID:23126925

  9. Opacity and gradients in aluminum wire array z-pinch implosions on the Z pulsed power facility

    SciTech Connect

    Ampleford, D. J., E-mail: damplef@sandia.gov; Hansen, S. B.; Jennings, C. A.; Jones, B.; Coverdale, C. A.; Harvey-Thompson, A. J.; Rochau, G. A.; Dunham, G.; Moore, N. W.; Harding, E. C.; Cuneo, M. E. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Chong, Y.-K.; Clark, R. W.; Ouart, N.; Thornhill, J. W.; Giuliani, J.; Apruzese, J. P. [Naval Research Laboratory, Washington, DC 20375 (United States)] [Naval Research Laboratory, Washington, DC 20375 (United States)

    2014-03-15

    Aluminum wire array z pinches imploded on the Z generator are an extremely bright source of 1–2?keV radiation, with close to 400?kJ radiated at photon energies >1?keV and more than 50?kJ radiated in a single line (Al Ly-?). Opacity plays a critical role in the dynamics and K-shell radiation efficiency of these pinches. Where significant structure is present in the stagnated pinch this acts to reduce the effective opacity of the system as demonstrated by direct analysis of spectra. Analysis of time-integrated broadband spectra (0.8–25?keV) indicates electron temperatures ranging from a few 100?eV to a few keV are present, indicative of substantial temperature gradients.

  10. Explosive Z Pinch

    E-print Network

    Francesco Giacosa; Ralf Hofmann; Markus Schwarz

    2006-11-08

    We propose an explanation for the recently observed powerful contained explosion in a Z pinch experiment performed at Sandia National Laboratories. Our arguments are based on the assumption that a pure SU(2) Yang-Mills theory of scale $\\sim 0.5 $MeV is responsible for the emergence of the electron and its neutrino.

  11. 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 [Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

    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.

  12. Fusion with Z-pinches

    SciTech Connect

    Cook, D.

    1998-06-01

    In the past thirty-six months, great progress has been made in x-ray production using high-current z-pinches. Today, the x-ray energy and power output of the Z accelerator (formerly PBFA-II) is the largest available in the laboratory. These z-pinch x-ray sources have the potential to drive high-yield ICF reactions at affordable cost if several challenging technical problems can be overcome. In this paper, the recent technical progress with Z-pinches will be described, and a technical strategy for achieving high-yield ICF with z-pinches will be presented.

  13. 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.

  14. 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.

  15. Development Path for Z-Pinch IFE

    Microsoft Academic Search

    C. Olson; G. Rochau; S. Slutz

    2005-01-01

    The long-range goal of the Z-Pinch IFE program is to produce an economically-attractive power plant using high-yield z-pinch-driven targets (â3GJ) with low rep-rate per chamber (â0.1 Hz). The present mainline choice for a Z-Pinch IFE power plant uses an LTD (Linear Transformer Driver) repetitive pulsed power driver, a Recyclable Transmission Line (RTL), a dynamic hohlraum z-pinch-driven target, and a thick-liquid

  16. Z-Pinch Experiments with Styrofoam Fibres and Plasmajets

    Microsoft Academic Search

    S. Stein; G. Decker; W. Kies; P. Röwekamp; G. Ziethen; K. Baumung; H. Bluhm; W. Ratajczak; D. Rusch; J. M. Bayley

    1994-01-01

    Z-pinch plasmas created from fibres are less prone to macroscopic instabilities than predicted by ideal MHD theory. However, solid fibre experiments at the pulseline KALIF (2 MV, 900 kA) gave disappointing results with respect to driver-load coupling and pinch plasma confinement. High power discharges led to current leaks and plasma expansion presumably due to lacking initial conductivity and compressibility. Therefore

  17. The physics of fast Z pinches

    Microsoft Academic Search

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

    2000-01-01

    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. At present Z pinches are the most intense laboratory x-ray sources (1.8 MJ in 5 ns from a

  18. 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.

  19. The physics of fast Z pinches

    SciTech Connect

    Ryutov, D.D. [Lawrence Livermore National Lab., CA (United States); Derzon, M.S.; Matzen, M.K. [Sandia National Labs., Albuquerque, NM (United States)

    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.

  20. Time-resolved x-ray absorption spectroscopy measurements of foils heated by z-pinch hohlraums

    Microsoft Academic Search

    J. E. Bailey; G. A. Chandler; C. Deeney; M. R. Douglas; D. Jobe; P. Lake; T. J. Nash; D. Nielson; R. B. Spielman; J. J. Macfarlane

    1999-01-01

    Z-pinch radiation is presently being used to heat hohlraums for inertial confinement fusion and high-energy-density physics investigations. A tamped aluminum foil mounted over an aperture in the hohlraum wall is exposed to a combination of tungsten plasma z-pinch radiation and wall re-emission. A time-gated x-ray crystal spectrograph views the pinch plasma through the foil, detecting characteristic tungsten plasma emission with

  1. Use of Z-pinch sources for high-pressure shock wave studies

    SciTech Connect

    Konrad, C.H.; Asay, J.R.; Hall, C.A. [and others

    1998-01-01

    In this paper, we will discuss the use of z-pinch sources for shock wave studies at multi-Mbar pressures. Experimental plans to use the technique for absolute shock Hugoniot measurements are discussed. Recent developments have demonstrated the use of pulsed power techniques for producing intense radiation sources (Z pinches) for driving planar shock waves in samples with spatial dimensions significantly larger than possible with other radiation sources. Initial indications are that using Z pinch sources for producing Planckian radiation sources in secondary hohlraums can be used to drive shock waves in samples with diameters to a few millimeters and thickness approaching one millimeter in thickness. These dimensions provides the opportunity to measure both shock velocity and the particle velocity behind the shock front with accuracy comparable to that obtained with gun launchers. In addition, the peak hohlraum temperatures of nearly 150 eV that are now possible with Z pinch sources result in shock wave pressures approaching 45 Mbar in high impedance materials such as tungsten and 10-15 Mbar in low impedance materials such as aluminum and plastics. In this paper, we discuss the use of Z pinch sources for making accurate absolute EOS measurements in the megabar pressure range.

  2. Progress on Z-pinch Inertial Fusion Energy

    Microsoft Academic Search

    C. L. Olson; G. Rochau; S. Slutz; C. Morrow; R. Olson; A. Parker; M. Cuneo; D. Hanson; G. Bennett; T. Sanford; J. Bailey; W. Stygar; R. Vesey; T. Mehlhorn; K. Struve; M. Mazarakis; M. Savage; A. Owen; T. Pointon; M. Kiefer; S. Rosenthal; L. Schneider; S. Glover; K. Reed; G. Benevides; D. Schroen; W. Krych; C. Farnum; M. Modesto; D. Oscar; L. Chhabildas; J. Boyes; V. Vigil; R. Keith; M. Turgeon; B. Smith; B. Cipiti; E. Lindgren; D. Smith; K. Peterson; V. Dandini; D. McDaniel; J. Quintenz; M. Matzen; J. P. VanDevender; W. Gauster; L. Shephard; M. Walck; T. Renk; T. Tanaka; M. Ulrickson; P. Peterson; J. De Groot; N. Jensen; R. Peterson; G. Pollock; P. Ottinger; J. Schumer; D. Kammer; I. Golovkin; G. Kulcinski; L. El-Guebaly; G. Moses; E. Mogahed; I. Sviatoslavsky; M. Sawan; M. Anderson; R. Gallix; N. Alexander; W. Rickman; H. Tran; P. Panchuk; W. Meier; J. Latkowski; R. Moir; R. Schmitt; R. Abbot; M. Abdou; A. Ying; P. Calderoni; N. Morley; S. Abdel-Khalik; D. Welch; D. Rose; W. Szaroletta; R. Curry; K. McDonald; D. Louie; S. Dean; A. Kim; S. Nedoseev; E. Grabovsky; A. Kingsep; V. Smirnov

    2004-01-01

    The long-range goal of the Z-pinch IFE program is to produce an economically-attractive power plant using high-yield Z-pinch-driven targets (?3 GJ) with low rep-rate per chamber (?0.1 Hz). He present mainline choice for a Z-pinch IFE power plant uses an LTD (Linear Transformer Driver) repetitive pulsed power driver, a Recyclable Transmission Line (RTL), a dynamic hohlraum Z-pinch-driven target, and a

  3. Spectroscopic study in Z-pinch discharge

    SciTech Connect

    Garamoon, A.A.; Saudy, A.H.; Shark, W. [Al-Azhar Univ., Cairo (Egypt)] [and others

    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.

  4. Wire ablation scaling in Z pinches

    NASA Astrophysics Data System (ADS)

    Yu, Edmund; Sinars, Daniel; Mehlhorn, Tom; Oliver, Bryan

    2004-11-01

    We investigate the physical processes involved in wire ablation in Z pinches, using a combination of simple 1D steady-state analytic theory (similar in approach to that described in [1]) and simulations of the Z pinch under constant current drive conditions (using the radiation-MHD code ALEGRA-MHD). Of particular interest is the dependence of mass ablation rate on wire mass and drive current. We benchmark our scaling trends against simulations of a recently conducted series of experiments on Sandia National Laboratories' Z accelerator (Albuquerque, NM), in which only the mass of the wire array was varied. [1] V.V. Aleksandrov et al., Plasma Phys. Reports 27, 89 (2001) *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockhead Martin Company for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  5. 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.

  6. A Z-Pinch Driven Fusion Reactor Concept

    Microsoft Academic Search

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

    1999-01-01

    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

  7. Investigation of plasma instabilities in the stagnated Z pinch.

    PubMed

    Ivanov, V V; Chittenden, J P; Mancini, R C; Papp, D; Niasse, N; Altemara, S D; Anderson, A A

    2012-10-01

    High-resolution laser probing diagnostics at a wavelength of 266 nm allow observation of the internal structure and instabilities in dense stagnated Z pinches, typically hidden by trailing material. The internal structure of the 1-MA Z pinch includes strong kink and sausage instabilities, loops, flares, and disruptions. Mid- and small-scale density perturbations develop in the precursor and main pinch. The three-dimensional shape and dynamics of the wire-array Z pinch are predetermined by the initial configuration of the wire array. Cylindrical, linear, and star wire-array Z pinches present different sets of instabilities seeded to the pinch at the implosion stage. Prolonged implosion of trailing mass can enhance x-ray production in wire arrays. Fast plasma motion with a velocity >100 km/s was observed in the Z pinch at stagnation with two-frame shadowgraphy. Development of instabilities in wire arrays is in agreement with three-dimensional magnetohydrodynamic simulations. PMID:23214696

  8. Z-pinch driven fusion energy

    SciTech Connect

    SLUTZ,STEPHEN A.; OLSON,CRAIG L.; ROCHAU,GARY E.; DERZON,MARK S.; PETERSON,P.F.; DEGROOT,J.S.; JENSEN,N.; MILLER,G.

    2000-05-30

    The Z machine at Sandia National Laboratories (SNL) is the most powerful multi-module synchronized pulsed-power accelerator in the world. Rapid development of z-pinch loads on Z has led to outstanding progress in the last few years, resulting in radiative powers of up to 280 TW in 4 ns and a total radiated x-ray energy of 1.8 MJ. The present goal is to demonstrate single-shot, high-yield fusion capsules. Pulsed power is a robust and inexpensive technology, which should be well suited for Inertial Fusion Energy, but a rep-rated capability is needed. Recent developments have led to a viable conceptual approach for a rep-rated z-pinch power plant for IFE. This concept exploits the advantages of going to high yield (a few GJ) at low rep-rate ({approximately} 0.1 Hz), and using a Recyclable Transmission Line (RTL) to provide the necessary standoff between the fusion target and the power plant chamber. In this approach, a portion of the transmission line near the capsule is replaced after each shot. The RTL should be constructed of materials that can easily be separated from the liquid coolant stream and refabricated for a subsequent shots. One possibility is that most of the RTL is formed by casting FLiBe, a salt composed of fluorine, lithium, and beryllium, which is an attractive choice for the reactor coolant, with chemically compatible lead or tin on the surface to provide conductivity. The authors estimate that fusion yields greater than 1 GJ will be required for efficient generation of electricity. Calculations indicate that the first wall will have an acceptable lifetime with these high yields if blast mitigation techniques are used. Furthermore, yields above 5 GJ may allow the use of a compact blanket direct conversion scheme.

  9. Evidence of stabilization in the Z-pinch.

    PubMed

    Shumlak, U; Golingo, R P; Nelson, B A; Den Hartog, D J

    2001-11-12

    Theoretical studies have predicted that the Z-pinch can be stabilized with a sufficiently sheared axial flow [U. Shumlak and C. W. Hartman, Phys. Rev. Lett. 75, 3285 (1995)]. A Z-pinch experiment is designed to generate a plasma which contains a large axial flow. Magnetic fluctuations and velocity profiles in the plasma pinch are measured. Experimental results show a stable period which is over 700 times the expected instability growth time in a static Z-pinch. The experimentally measured axial velocity shear is greater than the theoretical threshold during the stable period and approximately zero afterwards when the magnetic mode fluctuations are high. PMID:11690481

  10. An ICF system based on Z-pinch radiation produced by an explosive magnetic generator

    NASA Astrophysics Data System (ADS)

    Garanin, S. G.; Ivanovsky, A. V.; Mkhitariyan, L. S.

    2011-10-01

    It is known that a thermonuclear target can be ignited by an implosion accomplished with X-radiation generated by means of laser radiation conversion or by a Z pinch formed by a high-power current pulse. For these purposes laser facility NIF has been constructed in the USA, 'Megajoule' is being constructed in France and there is a project of laser facility UFL in Russia. The project of stationary facility X has been developed in SNL USA to produce a Z pinch capable of generating an x-ray pulse with parameters close to the ignition threshold. There is a great chance, however, that the already tested technologies, including disc explosive magnetic generators (DEMG), systems of current peaking based on electrically exploded foil opening switches and high-voltage switching devices, allow the intriguing problem of the ignition feasibility to be solved and the quickest and cheapest way to accomplish this to be provided. To explore this possibility, the paper will sequentially analyse the ignition conditions. The required parameters of Z pinch X-radiation and the size of the DEMG-based facility to obtain these parameters will be evaluated. Capabilities of the new current sources based on the DEMG and of the devices shaping a current pulse will be presented and compared with those required for the ignition.

  11. Z-Pinch Experiments with Styrofoam Fibres and Plasmajets

    NASA Astrophysics Data System (ADS)

    Stein, S.; Decker, G.; Kies, W.; Röwekamp, P.; Ziethen, G.; Baumung, K.; Bluhm, H.; Ratajczak, W.; Rusch, D.; Bayley, J. M.

    1994-03-01

    Z-pinch plasmas created from fibres are less prone to macroscopic instabilities than predicted by ideal MHD theory. However, solid fibre experiments at the pulseline KALIF (2 MV, 900 kA) gave disappointing results with respect to driver-load coupling and pinch plasma confinement. High power discharges led to current leaks and plasma expansion presumably due to lacking initial conductivity and compressibility. Therefore two alternative schemes have been investigated: Solid fibres were replaced by styrofoam fibres with about 1 % solid density and plasmajets of a deuterium-argon mixture. Analyses of the experimental results showed no major differences between styrofoam and solid fibres. However, the plasmajet experiments resulted in significant improvements with respect to the initial discharge behaviour. Unfortunately, severe pinch disruptions about 40 ns after discharge initiation prevented pinch formation and confinement. The high electric field of the pulseline KALIF and the low density of the jet plasma (E/n > 10-15 Vm2) resulted in runaway electrons and plasma erosion rather than in magnetic confinement to the pinch.

  12. Rapid solidification of aluminum die cast alloys by high-power laser radiation

    Microsoft Academic Search

    Heinz Haferkamp; Ferdinand von Alvensleben; Oliver Thuerk

    1998-01-01

    Rapid solidification of aluminum alloys during the remelting process using high power laser radiation results in refined effects of the solidified grain texture and improved wear resistance and material hardness. High temperature gradients can be achieved, and energy coupling into the aluminum alloy is locally restricted and can be precisely controlled. For the adjustment of defined grain textures, the dynamic

  13. Simulation of Wire-Array Z Pinches with ALEGRA

    Microsoft Academic Search

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

    2006-01-01

    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

  14. Self-Organized Structures In Z-Pinch Devices

    NASA Astrophysics Data System (ADS)

    Ortiz-Tapia, Arturo

    2006-12-01

    In several z-pinch devices there has been observation of regular structures, which appear systematically when repeating the experiments. The fact that very identifiable, recurrent, geometrical structures appear in z-pinches, which are relatively long lived, has motivated the analysis of the experimental data from the point of view of self-organization: there is an input of energy in the form of Joule heating, and densely magnetized plasma is formed, stabilized by several MHD effects and the expulsion of entropy.

  15. Energetic Electron Beams in Conical Wire Array Z-Pinches

    NASA Astrophysics Data System (ADS)

    Presura, R.; Wallace, M. S.; Haque, S.; Arias, A.; Quiros, N.

    2013-10-01

    Intense beams of energetic electrons are often inferred in z-pinch experiments. Using magnetic deflection and Faraday cup detection we diagnosed electron beams with energies in the range 0.1-1 MeV produced in conical wire array z-pinches and x-pinches. The experiments were performed on the 1 MA Zebra z-pinch at the Nevada Terawatt Facility. The divergence of the beams and variations in pointing from one emission episode to another reduced the accuracy of these measurements and are subject of further investigation. However, the temporal characteristics of the electron beams can be correlated with the x-ray emission of the z-pinches. Results of these measurements will be presented. Intense beams of energetic electrons are often inferred in z-pinch experiments. Using magnetic deflection and Faraday cup detection we diagnosed electron beams with energies in the range 0.1-1 MeV produced in conical wire array z-pinches and x-pinches. The experiments were performed on the 1 MA Zebra z-pinch at the Nevada Terawatt Facility. The divergence of the beams and variations in pointing from one emission episode to another reduced the accuracy of these measurements and are subject of further investigation. However, the temporal characteristics of the electron beams can be correlated with the x-ray emission of the z-pinches. Results of these measurements will be presented. This work was supported by the U.S. Department of Energy, NNSA grant DE-NA0001834. Use of the Nevada Terawatt Facility was supported by DOE, NNSA, under Contract No. DE-FC52-06NA27616.

  16. Faraday Rotation Measurements on Z-Pinches Final Report

    SciTech Connect

    Greenley, J.B.

    1998-10-01

    The Campus Executive Program sponsored this research at Cornell University. The research was directed toward the implementation of laser-based diagnostics for wire-array Z-pinches. Under this contract we were able to carry out all the necessary preparations to setup the laser diagnostics to complement our x-ray backlighting measurements of the early phase of exploding wire z-pinch plasma formation.

  17. The high density Z-pinch

    SciTech Connect

    McCall, G.H.

    1988-01-01

    During the past few years techniques have been developed for producing pinches in solid deuterium. The conditions which exist in these plasmas are quiet different from those produced earlier. The pinch is formed from a fiber of solid deuterium rather than from a low density gas, and the current is driven by a low impedance, high voltage pulse generator. Because of the high initial density, it is not necessary to compress the pinch to reach thermonuclear conditions, and the confinement time required for energy production is much shorter than for a gas. The experimental results, which have been verified by experiments performed at higher current were quite surprising and encouraging. The pinch appeared to be stable for a time much longer than the Alfven radial transit time. In this paper, however, I argue that the pinch is not strictly stable, but it does not appear to disassemble in a catastrophic fashion. It appears that there may be a distinction between stability and confinement in the high density pinch. In the discussion below I will present the status of the high density Z-pinch experiments at laboratories around the world, and I will describe some of the calculational and experimental results. I will confine my remarks to recent work on the high density pinch. 17 refs. 10 figs.

  18. 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.

  19. 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.

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

    Microsoft Academic Search

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

    2011-01-01

    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

  1. Seeded Perturbations in Wire Array Z-Pinches

    SciTech Connect

    Jones, B.; Deeney, C.; McKenney, J.L.; Garasi, C.J.; Mehlhorn, T.A.; Robinson, A.C.; Wunsch, S.E.; Coverdale, C.A. [Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185 (United States); LePell, P.D. [Ktech Corp., Albuquerque, NM 87123 (United States); Bland, S.N.; Lebedev, S.V.; Chittenden, J.P.; Bott, S.C.; Ampleford, D.J.; Palmer, J.B.A.; Hall, G.N.; Rapley, J. [Blackett Laboratory, Imperial College, London, SW7 2BZ (United Kingdom); Oliver, B.V. [Mission Research Corp., Albuquerque, NM 87110 (United States); Safronova, A.S.; Kantsyrev, V. [Department of Physics, University of Nevada, Reno, NV 89557 (United States)] (and others)

    2006-01-05

    Controlled seeding of perturbations is employed to study the evolution of wire array z-pinch implosion instabilities which strongly impact x-ray production when the 3D plasma stagnates on axis. Wires modulated in radius exhibit locally enhanced magnetic field and imploding bubble formation at discontinuities in wire radius due to the perturbed current path. Wires coated with localized spectroscopic dopants are used to track turbulent material flow. Experiments and MHD modeling offer insight into the behavior of z-pinch instabilities.

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

    PubMed

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

    2010-08-01

    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/mum), 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. PMID:20815603

  3. Seeded perturbations in wire array Z-Pinches.

    SciTech Connect

    Robinson, Allen Conrad; Fedin, Dmitry (University of Nevada, Reno); Kantsyrev, Victor Leonidovich (University of Nevada, Reno); Wunsch, Scott Edward; Oliver, Bryan Velten (Mission Research); Lebedev, Sergey V. (Imperial College); Coverdale, Christine Anne; Ouart, Nicholas D. (University of Nevada, Reno); LePell, Paul David (Ktech Corporation); Safronova, Alla S. (University of Nevada, Reno); Shrestha, I. (University of Nevada, Reno); McKenney, John Lee; Ampleford, David J. (Imperial College); Rapley, J. (Imperial College); Bott, S. C. (Imperial College); Palmer, J. B. A. (Imperial College); Sotnikov, Vladimir Isaakovich (University of Nevada, Reno); Bland, Simon Nicholas (Imperial College); Ivanov, Vladimir V. (University of Nevada, Reno); Chittenden, Jeremy Paul (Imperial College); Jones, B.; Garasi, Christopher Joseph; Hall, Gareth Neville (Imperial College); Yilmaz, M. Faith (University of Nevada, Reno); Mehlhorn, Thomas Alan; Deeney, Christopher; Pokala, S. (University of Nevada, Reno); Nalajala, V. (University of Nevada, Reno)

    2005-07-01

    Controlled seeding of perturbations is employed to study the evolution of wire array z-pinch implosion instabilities which strongly impact x-ray production when the 3D plasma stagnates on axis. Wires modulated in radius exhibit locally enhanced magnetic field and imploding bubble formation at discontinuities in wire radius due to the perturbed current path. Wires coated with localized spectroscopic dopants are used to track turbulent material flow. Experiments and MHD modeling offer insight into the behavior of z-pinch instabilities.

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

    PubMed

    Rochau, Gregory A; Bailey, J E; Macfarlane, J J

    2005-12-01

    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 MgF2 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-->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 1sigma to the best-fit conditions. This agreement indicates that both the driving radiation spectrum and the heating of the Al and MgF2 samples is understood within the accuracy of the spectroscopic method. PMID:16486068

  5. Study of Three-Dimensional Structure in Wire-Array Z Pinches by Controlled Seeding of Axial Modulations in Wire Radius

    SciTech Connect

    Jones, B.; Deeney, C.; McKenney, J.L.; Garasi, C.J.; Mehlhorn, T.A.; Robinson, A.C.; Wunsch, S.E. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Bland, S.N.; Lebedev, S.V.; Chittenden, J.P.; Bott, S.C.; Ampleford, D.J.; Palmer, J.B.A.; Rapley, J.; Hall, G.N. [Blackett Laboratory, Imperial College, London, SW7 2BZ (United Kingdom); Oliver, B.V. [Mission Research Corporation, Albuquerque, New Mexico 87110 (United States)

    2005-11-25

    Three-dimensional perturbations have been seeded in wire-array z pinches by etching 15 {mu}m diameter aluminum wires to introduce 20% modulations in radius with a controlled axial wavelength. These perturbations seed additional three-dimensional imploding structures that are studied experimentally and with magnetohydrodynamics calculations, highlighting the role of current path nonuniformity in perturbation-induced magnetic bubble formation.

  6. Laser pumping by intense discharges in z-pinch geometry.

    PubMed

    Buser, R G; Ramm, D

    1966-04-01

    Optical properties of high-current, low-pressure, noble-gas discharges in z-pinch geometry are studied and compared with theta-pinch discharges and standard commercial light sources. Results indicate possible usefulness in systems where high peak power, high repetition rates or high uv content are demanded. PMID:20048907

  7. Measurement of radiation symmetry in Z-pinch-driven hohlraums

    Microsoft Academic Search

    D. L. Hanson; R. A. Vesey; M. E. Cuneo; J. L. Porter; G. A. Chandler; L. E. Ruggles; W. W. Simpson; J. Torres; J. McGurn; D. Hebron; S. C. Dropinski; J. H. Hammer; G. R. Bennett; H. Seaman; T. L. Gilliland; D. G. Schroen

    2002-01-01

    The Z-pinch-driven hohlraum (ZPDH) [J. H. Hammer et al., Phys. Plasmas 6, 2129 (1999)] is a promising approach to high yield inertial confinement fusion currently being characterized in experiments on the Sandia Z accelerator [M. E. Cuneo et al., Phys. Plasmas 8, 2257 (2001)]. Simulations show that capsule radiation symmetry, a critical issue in ZPDH design, is governed primarily by

  8. 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.

  9. An Inertial-Fusion Z-Pinch Power Plant Concept

    SciTech Connect

    DERZON,MARK S.; ROCHAU,GARY E.; DEGROOT,J.; OLSON,CRAIG L.; PETERSON,P.; PETERSON,R.R.; SLUTZ,STEPHEN A.; ZAMORA,ANTONIO J.

    2000-12-15

    With the promising new results of fast z-pinch technology developed at Sandia National Laboratories, we are investigating using z-pinch driven high-yield Inertial Confinement Fusion (ICF) as a fusion power plant energy source. These investigations have led to a novel fusion system concept based on an attempt to separate many of the difficult fusion engineering issues and a strict reliance on existing technology, or a reasonable extrapolation of existing technology, wherever possible. In this paper, we describe the main components of such a system with a focus on the fusion chamber dynamics. The concept works with all of the electrically-coupled ICF proposed fusion designs. It is proposed that a z-pinch driven ICF power system can be feasibly operated at high yields (1 to 30 GJ) with a relatively low pulse rate (0.01-0.1 Hz). To deliver the required current from the rep-rated pulse power driver to the z-pinch diode, a Recyclable Transmission Line (RTL) and the integrated target hardware are fabricated, vacuum pumped, and aligned prior to loading for each power pulse. In this z-pinch driven system, no laser or ion beams propagate in the chamber such that the portion of the chamber outside the RTL does not need to be under vacuum. Additionally, by utilizing a graded-density solid lithium or fluorine/lithium/beryllium eutectic (FLiBe) blanket between the source and the first-wall the system can breed its own fuel absorb a large majority of the fusion energy released from each capsule and shield the first-wall from a damaging neutron flux. This neutron shielding significantly reduces the neutron energy fluence at the first-wall such that radiation damage should be minimal and will not limit the first-wall lifetime. Assuming a 4 m radius, 8 m tall cylindrical chamber design with an 80 cm thick spherical FLiBe blanket, our calculations suggest that a 20 cm thick 6061-T6 Al chamber wall will reach the equivalent uranium ore radioactivity level within 100 years after a 30 year plant operation. The implication of this low radioactivity is that a z-pinch driven power plant may not require deep geologic waste storage.

  10. Seeded perturbations in wire array z-pinches.

    SciTech Connect

    Robinson, Allen Conrad; Kantsyrev, Victor Leonidovich (University of Nevada, Reno, NV); Wunsch, Scott Edward; Oliver, Bryan Velten (Mission Research Corporation, Albuquerque, NM); Lebedev, Sergey V. (Imperial College, London, UK); Safronova, Alla S. (University of Nevada, Reno, NV); Maxwell, J. (Los Alamos National Laboratory, Los Alamos, NM); McKenney, John Lee; Ampleford, David J. (Imperial College, London, UK); Rapley, J. (Imperial College, London, UK); Bott, S. C. (Imperial College, London, UK); Palmer, J. B. A. (Imperial College, London, UK); Bland, Simon Nicholas (Imperial College, London, UK); Jones, Brent Manley; Chittenden, Jeremy Paul (Imperial College, London, UK); Garasi, Christopher Joseph; Hall, Gareth Neville (Imperial College, London, UK); 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.

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

    Microsoft Academic Search

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

    2008-01-01

    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 >200eV. The time-dependent 300 400 eV electron temperature and 15 35mg\\/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

  12. Capsule implosions driven by a z-pinch dynamic hohlraum

    Microsoft Academic Search

    J. E. Bailey; G. R. Bennett; G. A. Chandler; G. Cooper; D. E. Hebron; J. S. Lash; T. J. Nash; C. L. Ruiz; S. A. Slutz; R. A. Vesey; P. Lake; D. S. Nielson; R. Smelser; D. G. Schroen-Carey; J. J. Macfarlane

    2000-01-01

    Capsule implosions driven by z-pinch dynamic hohlraums are a promising avenue for ICF research. The goal of the experiments described here is to produce Ar K-shell x-rays that can be used to constrain implosion simulations and be exploited in future symmetry measurements. The configuration uses a 2-mm-diameter CH capsule filled with 12 atm D2\\/ 0.012 atm Ar, embedded in a

  13. Architecture of petawatt-class z-pinch accelerators

    NASA Astrophysics Data System (ADS)

    Stygar, W. A.; Cuneo, M. E.; Headley, D. I.; Ives, H. C.; Leeper, R. J.; Mazarakis, M. G.; Olson, C. L.; Porter, J. L.; Wagoner, T. C.; Woodworth, J. R.

    2007-03-01

    We have developed an accelerator architecture that can serve as the basis of the design of petawatt-class z-pinch drivers. The architecture has been applied to the design of two z-pinch accelerators, each of which can be contained within a 104-m-diameter cylindrical tank. One accelerator is driven by slow (˜1?s) Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses (?1?s) required to drive z pinches. The other is powered by linear transformer drivers (LTDs), which are less mature but produce much shorter pulses than conventional Marxes. Consequently, an LTD-driven accelerator promises to be (at a given pinch current and implosion time) more efficient and reliable. The Marx-driven accelerator produces a peak electrical power of 500 TW and includes the following components: (i) 300 Marx generators that comprise a total of 1.8×104 capacitors, store 98 MJ, and erect to 5 MV; (ii) 600 water-dielectric triplate intermediate-store transmission lines, which also serve as pulse-forming lines; (iii) 600 5-MV laser-triggered gas switches; (iv) three monolithic radial-transmission-line impedance transformers, with triplate geometries and exponential impedance profiles; (v) a 6-level 5.5-m-diameter 15-MV vacuum insulator stack; (vi) six magnetically insulated vacuum transmission lines (MITLs); and (vii) a triple-post-hole vacuum convolute that adds the output currents of the six MITLs, and delivers the combined current to a z-pinch load. The accelerator delivers an effective peak current of 52 MA to a 10-mm-length z pinch that implodes in 95 ns, and 57 MA to a pinch that implodes in 120 ns. The LTD-driven accelerator includes monolithic radial transformers and a MITL system similar to those described above, but does not include intermediate-store transmission lines, multimegavolt gas switches, or a laser trigger system. Instead, this accelerator is driven by 210 LTD modules that include a total of 1×106 capacitors and 5×105 200-kV electrically triggered gas switches. The LTD accelerator stores 182 MJ and produces a peak electrical power of 1000 TW. The accelerator delivers an effective peak current of 68 MA to a pinch that implodes in 95 ns, and 75 MA to a pinch that implodes in 120 ns. Conceptually straightforward upgrades to these designs would deliver even higher pinch currents and faster implosions.

  14. X-ray power increase from symmetrized wire-array z-pinch implosions

    SciTech Connect

    Sanford, T.W.L.; Allshouse, G.O.; Marder, B.M. [and others

    1996-08-01

    A systematic experimental study of annular aluminum-wire z-pinches on the Saturn accelerator shows that, for the first time, the measured spatial characteristics and x-ray powers can approach those of two-dimensional, radiation-magneto-hydrodynamic simulations when large numbers of wires are used. Calculations show that the implosion begins to transition from that of individual plasma wires to that of a continuous plasma shell, when the circumferential gap between wires in the array is reduced below 1.4+1.3/-0.7 mm. This calculated gap coincides with the measured transition of 1.4 {+-}0.4 mm between the observed regimes of slow and rapid improvement in power output with decreasing gap. In the plasma shell regime, x-ray powers in excess of a factor of three over that generated in the plasma-wire region are measured.

  15. Plasma channel and z-pinch dynamics for heavy ion transport

    Microsoft Academic Search

    David Miguel Ponce-Marquez

    2002-01-01

    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

  16. The study of the framing technology on Z-Pinch plasma imaging diagnosticate

    Microsoft Academic Search

    Shaotong Zhou; Xianbin Huang; Libing Yang; Rongguo Zhou; Wenda Peng; Jinyuan Liu; Lihong Niu

    2008-01-01

    The study of Z-Pinch plasma dynamics is base on space and time resolution diagnosticate. The article introduces that the principle and the configuration of a x-ray framing camera which is used on Z-pinch plasma dynamics process diagnosticate. The technology about anti-jamming and the frame pulse synchronization and delay was studied in experiments. The legible framing images of Z-Pinch plasma was

  17. A time-resolved spectroscopic diagnostic based on fast scintillator and optical fiber array for z-pinch plasmas.

    PubMed

    Ye, Fan; Qin, Yi; Jiang, Shuqing; Xue, Feibiao; Li, Zhenghong; Yang, Jianlun; Xu, Rongkun; Anan'ev, S S; Dan'ko, S A; Kalinin, Yu G

    2009-10-01

    We report a specially designed type of temporal resolved x-ray spectroscopic diagnostic using a spherically bent quartz crystal for z-pinch plasmas. Registration of time-resolved spectra was accomplished by coupling fast plastic scintillator, an optical fiber array, an optical streak camera, and a charge coupled device as the recording medium of this diagnostic. The diagnostic has been tested in imploding wire array experiments on S-300 pulsed power facility. Time-resolved K-shell lines were successfully obtained for aluminum wire array implosion plasmas. PMID:19895094

  18. The Prospects for High-Yield ICF with a Z-Pinch Driven Dynamic Hohlraum

    SciTech Connect

    CHANDLER, GORDON A.; CHRIEN, R.; COOPER, GARY WAYNE; DERZON, MARK S.; DOUGLAS, MELISSA R.; HEBRON, DAVID E.; LASH, JOEL S.; LEEPER, RAMON J.; MATZEN, M. KEITH; MEHLHORN, THOMAS A.; NASH, THOMAS J.; OLSON, RICHARD E.; PETERSON, D.L.; RUIZ, CARLOS L.; SANFORD, THOMAS W. L.; SLUTZ, STEPHEN A.

    1999-09-07

    Recent success with the Sandia Z machine has renewed interest in utilizing fast z-pinenes for ICF. One promising concept places the ICF capsule internal to the imploding z-pinch. At machine parameters relevant to achieving high yield, the imploding z-pinch mass has sufficient opacity to trap radiation giving rise to a dynamic hohlraum. The concept utilizes a 12 MJ, 54 MA z-pinch driver producing a capsule drive temperature exceeding 300 eV to realize a 550 MJ thermonuclear yield. They present the current high-yield design and its development that supports high-yield ICF with a z-pinch driven dynamic hohlraum.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

    2014-12-01

    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 scaling analyses will be presented. In addition to studying fundamental plasma science and high energy density physics, the ZaP and ZaP-HD experiments can be applied to laboratory astrophysics.

  1. Radiating shock measurements in the Z-pinch dynamic hohlraum.

    PubMed

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

    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. PMID:18517878

  2. Reversed current structure in a Z-pinch plasma

    PubMed

    Lee; Kim; Kim

    2000-10-30

    The current profile of a Z-pinch plasma is investigated using a one-dimensional magnetohydrodynamic code. Simulation results reveal the formation of a reversed current profile, its propagation, and an ejection of plasma at boundary region, which have been observed in previous experiments. A new physical mechanism is proposed to account for such phenomena. The physical mechanism involves the propagation of a shock wave. It is found that a reversed current profile appears when a shock wave reflected at axis expands in a compressing plasma column. PMID:11041939

  3. Nonlinear Rayleigh-Taylor instabilities in fast Z pinches

    SciTech Connect

    Miles, Aaron R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    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.

  4. Nonlinear Rayleigh-Taylor instabilities in fast z-pinches

    SciTech Connect

    Miles, A R

    2008-09-16

    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 (RT) 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 (CR) attainable for an axially coherent pinch. Both the implosion and instability models are validated with results from high-resolution numerical simulations.

  5. Investigation of trailing mass in Z-pinch implosions and comparison to experiment

    NASA Astrophysics Data System (ADS)

    Yu, Edmund

    2007-11-01

    Wire-array Z pinches represent efficient, high-power x-ray sources with application to inertial confinement fusion, high energy density plasmas, and laboratory astrophysics. The first stage of a wire-array Z pinch is described by a mass ablation phase, during which stationary wires cook off material, which is then accelerated radially inwards by the JxB force. The mass injection rate varies axially and azimuthally, so that once the ablation phase concludes, the subsequent implosion is highly 3D in nature. In particular, a network of trailing mass and current is left behind the imploding plasma sheath, which can significantly affect pinch performance. In this work we focus on the implosion phase, electing to model the mass ablation via a mass injection scheme. Such a scheme has a number of injection parameters, but this freedom also allows us to gain understanding into the nature of the trailing mass network. For instance, a new result illustrates the role of azimuthal correlation. For an implosion which is 100% azimuthally correlated (corresponding to an azimuthally symmetric 2D r-z problem), current is forced to flow on the imploding plasma sheath, resulting in strong Rayleigh-Taylor (RT) growth. If, however, the implosion is not azimuthally symmetric, the additional azimuthal degree of freedom opens up new conducting paths of lower magnetic energy through the trailing mass network, effectively reducing RT growth. Consequently the 3D implosion experiences lower RT growth than the 2D r-z equivalent, and actually results in a more shell-like implosion. A second major goal of this work is to constrain the injection parameters by comparison to a well-diagnosed experimental data set, in which array mass was varied. In collaboration with R. Lemke, M. Desjarlais, M. Cuneo, C. Jennings, D. Sinars, E. Waisman

  6. Time-Resolved 1-D X-ray Imaging Technique for Z-Pinch Plasma Diagnosis

    SciTech Connect

    Yang, J.L.; Li, Z.H.; Xu, R.K.; Li, L.B.; Ning, J.M.; Guo, C.; Song, F.J.; Xu, Z.P.; Xia, G.X. [Institute of Nuclear Physics and Chemistry, P.O.Box 919-212, Mianyang 621900 (China)

    2006-01-05

    A sensitive time-resolved 1-D x-ray imaging system with linear energy response to 100eV-2keV x-rays is developed and applied in Z-Pinch experiments to investigate time dependent x-ray distribution with one-dimensional(1-D) spatial resolution of 0.1mm{approx}0.4mm and temporal resolution of 3ns. A slit in the system relays the 1-D image of the pinch plasma to a plastic scintillator foil with a thickness of 0.2mm which converts x-ray to visible and near-infrared light and has linear response to x-ray energy. With an optical fiber array consisting of 40 linearly arranged individual fibers behind the scintillator foil, it is capable of transmitting the 1-D image out from within the vacuum chamber. The optical fiber array is subsequently coupled to a streak camera via optical fiber bundle consisting of 40 individual 30-meter-long fibers to allow the investigation of time-resolved 1D x-ray distribution. To avoid viewing the plasma-generated visible light and covering aluminum foil on the scintillator, both the scintillator foil and the fiber array are tilted at an angle of 45 degrees from the line of sight. This diagnostic system has been successfully applied in gas-puff and tungsten wire-array Z-Pinch experiments carried out on Qiang-Guang-1, S-300, and Angara-5-1 facilities for time-resolved measurement of x-ray power distribution along the axis or radius of the imploding plasma. In these experiments, the current is in the range of 1-3MA and the x-ray radiation energy is in the order of 10-50kJ. Some experimental results will be presented in this paper.

  7. Self-organized structures in z-pinch devices

    NASA Astrophysics Data System (ADS)

    Ortíz-Tapia, Arturo

    2002-11-01

    In several z-pinch devices there has been observation of regular structures, which appear systematically when repeating the experiments. The fact that very identifiable, recurrent, geometrical structures appear in z-pinches, which are relatively long lived, has motivated the analysis of the experimental data in a way that would cast light over these structures. In order to study this problem, diagnostic methods such as Schlieren photography, Quadro camera diagnostics, X-ray diagnostics, interferometry measurements and streak camera were used. This work includes analysis of experimental results, and the determination of some of the parameters which probably give rise to self-organized structures and some regular structures. It was found that a major contributor, for self-organization to occur, was the dominance of electromagnetic energy over the kinetic energy in the wire corona. The induction of an azimuthal magnetic field contributed to the generation of azimuthal currents, which in turn induced an axial magnetic field. Both axial and azimuthal magnetic fields contributed to the formation of helical-like structures, at least until the pinch began to dissipate. An important stabilizing factor for the plasma channel could have been played by the solid remains of part of the fiber inside the channel. There is a positive strong correlation between the expulsion of entropy and the persistence in the existence of self-organized structures.

  8. Thermal Analysis of the Z-Pinch Power Plant Concept

    SciTech Connect

    Modesto, M.A.; Lindgren, E.R.; Morrow, C.W. [Sandia National Laboratories (United States)

    2005-04-15

    In this work, a preliminary thermal model for the Z-Pinch Power Plant is presented. This power plant utilizes fusion energy to generate electric energy in the GW range. The Z-Pinch Technology consists of compressing high-density plasma to produce X-rays to indirectly heat to ignition a deuterium/tritium fusion capsule. This ignition releases a minimum of 3 GJ every 10 seconds. The thermal energy generated is absorbed by the primary cycle fluid, and it is later used to power a Brayton or Rankine cycle. An advanced heat exchanger is used as the interface between the two cycles. This heat exchanger plays an important role in power plant performance. Three fluids (Flibe, Pb-17Li, and Li) were used for the plant performance analysis. The thermodynamic properties of the selected fluids determine the maximum operating temperature of the power cycles. Model results show that high temperatures (over 1000 deg. C) are developed in the primary cycle as needed to efficiently run the secondary cycle. The results of the performance parametric study demonstrated that the Brayton cycle exhibits better performance characteristics than the Rankine cycle for this type of application.

  9. Z pinch driven inertial confinement fusion target physics research at Sandia National Laboratories

    Microsoft Academic Search

    R. J. Leeper; T. E. Alberts; J. R. Asay; P. M. Baca; K. L. Baker; S. P. Breeze; G. A. Chandler; D. L. Cook; G. W. Cooper; C. Deeney; M. S. Derzon; M. R. Douglas; D. L. Fehl; T. Gilliland; D. E. Hebron; M. J. Hurst; D. O. Jobe; J. W. Kellogg; J. S. Lash; S. E. Lazier; M. K. Matzen; D. H. McDaniel; J. S. McGurn; T. A. Mehlhorn; A. R. Moats; R. C. Mock; D. J. Muron; T. J. Nash; R. E. Olson; J. L. Porter; J. P. Quintenz; P. V. Reyes; L. E. Ruggles; C. L. Ruiz; T. W. L. Sanford; F. A. Schmidlapp; J. F. Seamen; R. B. Spielman; M. A. Stark; K. W. Struve; W. A. Stygar; D. R. Tibbetts-Russell; J. A. Torres; M. Vargas; T. C. Wagoner; C. Wakefield; J. H. Hammer; D. D. Ryutov; M. Tabak; S. C. Wilks; R. L. Bowers; K. D. McLenithan; D. L. Peterson

    1999-01-01

    Three hohlraum concepts are being pursued at Sandia National Laboratories (SNL) to investigate the possibility of using pulsed power driven magnetic implosions (Z pinches) to drive targets capable of fusion yields in the range 200-1000 MJ. This research is being conducted on SNL's Z facility, which is capable of driving peak currents of 20 MA in various Z pinch load

  10. High-power 266 nm ultraviolet generation in yttrium aluminum borate.

    PubMed

    Liu, Qiang; Yan, Xingpeng; Gong, Mali; Liu, Hua; Zhang, Ge; Ye, Ning

    2011-07-15

    A yttrium aluminum borate [YAl(3)(BO(3))(4)] (YAB) crystal with UV cutoff wavelength of 165 nm is used as the nonlinear optical crystal for fourth harmonic generation. The fundamental frequency laser at 1064 nm from an Nd:YVO(4) master oscillator power amplifier laser was frequency doubled to 532 nm. Using the type I phase-matching YAB crystal, a 5.05 W average power 266 nm UV laser was obtained at the pulse repetition frequency of 65 kHz, corresponding to the conversion efficiency of 12.3% from 532 to 266 nm. The experimental results show great potential for the application of using YAB as a nonlinear optical crystal to get high-power fourth harmonic generation. PMID:21765498

  11. High-power 266?nm ultraviolet generation in yttrium aluminum borate

    NASA Astrophysics Data System (ADS)

    Liu, Qiang; Yan, Xingpeng; Gong, Mali; Liu, Hua; Zhang, Ge; Ye, Ning

    2011-07-01

    A yttrium aluminum borate [YAl3(BO3)4] (YAB) crystal with UV cutoff wavelength of 165nm is used as the nonlinear optical crystal for fourth harmonic generation. The fundamental frequency laser at 1064nm from an Nd:YVO4 master oscillator power amplifier laser was frequency doubled to 532nm. Using the type I phase-matching YAB crystal, a 5.05W average power 266nm UV laser was obtained at the pulse repetition frequency of 65kHz, corresponding to the conversion efficiency of 12.3% from 532 to 266nm. The experimental results show great potential for the application of using YAB as a nonlinear optical crystal to get high-power fourth harmonic generation.

  12. 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,

  13. Fusion burn dynamics in dense Z-pinches (DZP)

    SciTech Connect

    Krakowski, R.A.; Miller, R.L.; Bathke, C.G.; Werley, K.A.; Hagenson, R.L. (Los Alamos National Lab., NM (USA); Phillips Petroleum Co., Bartlesville, OK (USA))

    1989-01-01

    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 endless, 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 are examined. 25 refs., 9 figs.

  14. The stability of the High-Density Z-Pinch

    SciTech Connect

    Glasser, A.H.; Nebel, R.A.

    1989-01-01

    Fiber-initiated High Density Z-Pinches at Los Alamos, NRL, and Karlsruhe have shown anomalously good stability. Kink modes are never seen, and sausage modes are at least delayed until late in the discharge. The success of these devices in reaching fusion conditions may depend on maintaining and understanding this anomalous stability. We have developed two numerical methods to study the stability in the regime where fluid theory is valid. While our methods are applicable to all modes, we will describe them only for the m = 0 sausage mode. The appearance of sausage modes late in the discharge and the total absence of kink modes suggest that an understanding of sausage modes is more urgent, and it is also simpler. 14 refs., 8 figs.

  15. Implosion dynamics in double planar wire array Z pinches

    SciTech Connect

    Williamson, K. M.; Kantsyrev, V. L.; Esaulov, A. A.; Safronova, A. S.; Cox, P.; Shrestha, I.; Osborne, G. C.; Weller, M. E.; Ouart, N. D.; Shlyaptseva, V. V. [Department of Physics, University of Nevada Reno, 1664 N. Virginia St. MS220 Reno, Nevada 89557 (United States)

    2010-11-15

    The double planar wire array (DPWA) Z pinch is a highly efficient radiation source with unique implosion dynamics and precursor formations. The inductively divided current successively ablates the wires and injects the material to the interior of the array. Three uniquely imploding DPWA load types were identified and classified according to the critical load parameter: low, intermediate, or high aspect ratio. Radiation pulse shaping was obtained from secondary precursors: off-axis mass carrying high current densities during the implosion phase. Time-gated EUV spectroscopy of off-axis mass accumulations is used to assess a 60 eV electron temperature prior to the implosion phase. These structures are shown to form by a different mechanism than the secondary precursors. High yields, compact size, and shaped radiation pulses merit further consideration of the DPWA as a candidate for inertial confinement fusion research.

  16. 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.

  17. Spectroscopic diagnosis of foam z-pinch plasmas on SATURN

    SciTech Connect

    Nash, T.J.; Derzon, M.S.; Allshouse, G.; Deeney, C.; Jobe, D.; McGurn, J. [Sandia National Labs., Albuquerque, NM (United States); MacFarlane, J.J.; Wang, P. [Wisconsin Univ., Madison, WI (United States)

    1996-06-01

    Solid and annular silicon aerogel and agar foams were shot on the accelerator SATURN to study plasma initiation, acceleration, and stagnation. SATURN delivers 7 MA with a 50 nsec rise time to these foam loads. We fielded several spectroscopic diagnostics to measure plasma parameters throughout the z-pinch discharge. A spatially resolved single frame time-gated EUV spectrometer measured the extent of plasma ablation off the surface foam. A time integrated crystal spectrometer showed that characteristic K shell radiation of silicon in the aerogel and of S and Na impurities in the agar were all attenuated when the foam loads were coated with a conductive layer of gold. The time resolved pinhole camera showed that in general the quality of the pinch implosions was poor but improved with increasing efforts to improve current continuity such as prepulse and conductive coatings.

  18. Spectroscopic diagnosis of foam z-pinch plasmas on SATURN

    SciTech Connect

    Nash, T.J.; Derzon, M.S.; Allshouse, G.; Deeney, C.; Jobe, D.; Seaman, J.; Gilliland, T.; McGurn, J. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1193 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-1193 (United States); MacFarlane, J.J.; Wang, P. [University of Wisconsin, Madison, Wisconsin (United States)] [University of Wisconsin, Madison, Wisconsin (United States)

    1997-01-01

    Solid and annular silicon aerogel and agar foams were imploded on the SATURN accelerator to study plasma initiation, acceleration, and stagnation. SATURN delivers 7 MA with a 50 ns rise time to these foam loads. We fielded several spectroscopic diagnostics to measure plasma parameters throughout the z-pinch discharge. A spatially resolved single frame time-gated extreme ultraviolet spectrometer measured the extent of plasma ablation off the surface of the foam. A time integrated crystal spectrometer showed that characteristic K shell radiation of silicon in the aerogel and of sulfur and sodium impurities in the agar were attenuated when the foam loads were coated with a conductive layer of gold. A time-resolved pinhole camera showed that in general the quality of the pinch implosions was poor but improved with increasing efforts to improve current continuity such as prepulse and conductive coatings. {copyright} {ital 1997 American Institute of Physics.}

  19. The effect of load thickness on Rayleigh-Taylor mitigation in high velocity, annular z pinch implosion

    SciTech Connect

    DOUGLAS,MELISSA R.; DEENEY,CHRISTOPHER; RODERICK,NORMAN F.

    2000-05-16

    Numerical calculations have been performed to investigate the role that load thickness may play in the performance of fast annular z pinch implosions. In particular, the effects of load thickness on the mitigation of the magnetically-driven Rayleigh-Taylor (RT) instability and energy coupling between the load and generator are addressed. using parameters representative of the Z accelerator [R.B.Spielman et al., Phys.Plasmas, 5, 2105 (1998)] at Sandia National Laboratories, two dimensional magnetohydrodynamic (MHD) simulations show that increased shell thickness results in lower amplitude, slightly longer wavelength RT modes. In addition, there appears to be an optimum in load velocity which is directly associated with the thickness of the sheath and subsequent RT growth. Thin, annular loads, which should couple efficiently to the accelerator, show a large reduction in implosion velocity due to extreme RT development and increased load inductance. As a consequence, thicker loads on the order of 5 mm, couple almost as efficiently to the generator since the RT growth is reduced. This suggests that z-pinch loads can be tailored for different applications, depending on the need for uniformity or high powers.

  20. X-ray imaging measurements of capsule implosions driven by a Z-pinch dynamic hohlraum.

    PubMed

    Bailey, J E; Chandler, G A; Slutz, S A; Bennett, G R; Cooper, G; Lash, J S; Lazier, S; Lemke, R; Nash, T J; Nielsen, D S; Moore, T C; Ruiz, C L; Schroen, D G; Smelser, R; Torres, J; Vesey, R A

    2002-08-26

    The radiation and shock generated by impact of an annular tungsten Z-pinch plasma on a 10-mm diam 5-mg/cc CH(2) foam are diagnosed with x-ray imaging and power measurements. The radiative shock was virtually unaffected by Z-pinch plasma instabilities. The 5-ns-duration approximately 135-eV radiation field imploded a 2.1-mm-diam CH capsule. The measured radiation temperature, shock radius, and capsule radius agreed well with computer simulations, indicating understanding of the main features of a Z-pinch dynamic-hohlraum-driven capsule implosion. PMID:12190409

  1. Progress in symmetric ICF capsule implosions and wire-array z-pinch source physics for double z-pinch driven hohlraums.

    SciTech Connect

    Bliss, David Emery; Vesey, Roger Alan; Rambo, Patrick K.; Lebedev, Sergey V. (Blackett Laboratory, Imperial College, London, UK); Hanson, David L.; Nash, Thomas J.; Yu, Edmund P.; Matzen, Maurice Keith; Afeyan, Bedros B. (Polymath Research, Inc., Pleasanton, CA); Smith, Ian Craig; Stygar, William A.; Porter, John Larry, Jr.; Cuneo, Michael Edward; Bennett, Guy R.; Campbell, Robert B.; Sinars, Daniel Brian; Chittenden, Jeremy Paul (Blackett Laboratory, Imperial College, London, UK); Waisman, Eduardo Mario; Mehlhorn, Thomas Alan

    2005-07-01

    Over the last several years, rapid progress has been made evaluating the double-z-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas 6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough to drive a high yield ICF capsule. The secondary hohlraum is irradiated from two sides by z-pinches to produce low odd-mode radiation asymmetry. This double-pinch source is driven from a single electrical power feed (Cuneo et al 2002 Phys. Rev. Lett. 88 215004) on the 20 MA Z accelerator. The double z-pinch has imploded ICF capsules with even-mode radiation symmetry of 3.1 {+-} 1.4% and to high capsule radial convergence ratios of 14-21 (Bennett et al 2002 Phys. Rev. Lett. 89 245002; Bennett et al 2003 Phys. Plasmas 10 3717; Vesey et al 2003 Phys. Plasmas 10 1854). Advances in wire-array physics at 20 MA are improving our understanding of z-pinch power scaling with increasing drive current. Techniques for shaping the z-pinch radiation pulse necessary for low adiabat capsule compression have also been demonstrated.

  2. Preliminary experiments on the production of high photon energy continuum radiation from a Z-pinch at the Z accelerator

    NASA Astrophysics Data System (ADS)

    Coverdale, C. A.; Deeney, C.; Harper-Slaboscewica, V. J.; Lepell, P. D.; Velikovich, A. L.; Davis, J.; Oreshkin, V. I.

    2003-10-01

    Traditionally, the generation of multi-keV x-ray radiation from Z-pinch plasmas has focused on K-shell emissions from moderate Z materials. While this approach has worked well, it requires increasingly higher energies be coupled to each ion to produce substantial output as the photon energy increases. An alternate approach to generating multi-keV radiation, proposed in Ref. 1, utilizes lower Z materials than are necessary to generate the appropriate K-shell lines, but tailors the Z-pinch load to overheat the plasma in order to enhance the recombination radiation that is generated. Initial experiments have been performed at the Z Accelerator to evaluate the level of recombination radiation that can be generated through the tailoring of initial load radius and mass with Aluminum and Titanium wire arrays. In this paper, the results of these experiments will be presented. Measurements of yield were made for several photon energy ranges and spectra were collected to evaluate the high energy continuum. These results will be compared with simulations and theoretical predictions to evaluate the feasibility of an overheated plasma for generating higher photon energy emissions. This work is supported by the Defense Threat Reduction Agency and the Department of Energy. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AI85000. *Ktech Corporation [1] A.L. Velikovich, et. al., Phys. Plasmas 8, 4509 (2001).

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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.

  4. Aluminum-doped lithium nickel cobalt oxide electrodes for high-power lithium-ion batteries.

    SciTech Connect

    Chen, C. H.; Liu, J.; Stoll, M. E.; Henriksen, G.; Vissers, D. R.; Amine, K.; Chemical Engineering; Univ. of Science and Technology of China

    2004-04-05

    Non-doped and aluminum-doped LiNi{sub 0.8}Co{sub 0.2}O{sub 2} cathodes from three industrial developers coupled with graphite anodes were made into lithium-ion cells for high-power applications. The powder morphology of the active cathode materials was examined by a scanning electron microscope. The electrochemical performance of these cells was investigated by hybrid pulse power characterization (HPPC) testing, accelerated aging, and AC impedance measurement of symmetric cells. Although all of the fresh cells are found to meet and exceed the power requirements set by PNGV, the power capability of those cells with non-doped LiNi {sub 0.8}Co{sub 0.2}O{sub 2} cathodes fades rapidly due to the rise of the cell impedance. Al-doping is found very effective to suppress the cell impedance rise by stabilizing the charge-transfer impedance on the cathode side. The stabilization mechanism may be related to the low average oxidation state of nickel ions in the cathode. The powder morphology also plays a secondary role in determining the impedance stabilization.

  5. Optimization of power density by decreasing the length of tungsten wire array Z pinches

    NASA Astrophysics Data System (ADS)

    Deeney, C.; Peterson, D. L.; Spielman, R. B.; Struve, K. W.; Chandler, G. A.

    1998-07-01

    Reducing the length of 30 mm diam tungsten wire arrays on the 20 MA Z pulsed power accelerator [R. B. Spielman, S. F. Breeze, C. Deeney et al., Proceedings of the 11th International Conference on Particle Beams, Prague, Czech Republic, edited by K. Junwirth and J. Ullschmied (Czech Academy of Sciences, Prague, 1996), p. 150] from 2 to 0.75 cm has shown that the radiated powers are energies that remain constant at 170±30 TW and 1600±150 kJ. The length-independent nature of the power and energy results in the radiated power per unit length increasing from 85±10 to 240±30 TW/cm. These high-power densities should result in approximately a 20% increase in radiation temperatures produced by a Z-pinch-driven vacuum or internal hohlarums. Two-dimensional radiation magnetohydrodynamic calculations indicate that the constant radiated energies with varying pinch lengths is consistent with the energy input being due to the work done by the Lorentz forces during the radial collapse, resulting in kinetic energy and during the on-axis pinch phase, resulting in pdV or compressional heating.

  6. Preliminary Results of a 10 kJ Z-Pinch

    SciTech Connect

    Cortazar, O. D.; Piriz, A. R.; Prieto, G. Rodriguez [Universidad de Castilla-La Mancha. E.T.S.I.I. Laboratorio de Plasmas y Descargas Electricas Campus de Ciudad Real-13071 Ciudad Real-Spain (Spain); Hoffmann, D. H. H.; Tahir, N. A. [G.S.I Darmstadt--Plasma Physics Division Planckstr 1-64291 Darmstadt--Germany (Germany)

    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.

  7. Preliminary Results of a 10 kJ Z-Pinch

    NASA Astrophysics Data System (ADS)

    Cortázar, O. D.; Piriz, A. R.; Prieto, G. Rodríguez; Hoffmann, D. H. H.; Tahir, N. A.

    2008-04-01

    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 ?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 SF6 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 107-108 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.

  8. 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%. PMID:23944569

  9. Study of the internal structure and small-scale instabilities in the dense Z pinch.

    PubMed

    Ivanov, V V; Chittenden, J P; Altemara, S D; Niasse, N; Hakel, P; Mancini, R C; Papp, D; Anderson, A A

    2011-10-14

    High-resolution laser diagnostics at the wavelength of 266 nm were applied for the investigation of Z pinches at the 1-MA generator. The internal structure of the stagnated Z pinches was observed in unprecedented detail. A dense pinch with strong instabilities was seen inside the column of the trailing plasma. Kink instability, disruptions, and micropinches were seen at the peak of the x-ray pulse and later in time. The three-dimensional structure of the stagnated Z pinch depends on the initial wire-array configuration and implosion scenario. Small-scale density perturbations were found in the precursor plasma and in the stagnated Z pinch. Development of instabilities is in agreement with three-dimensional magnetohydrodynamic simulations. PMID:22107394

  10. 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. [Cornell University Laboratory of Plasma Studies, 439 Rhodes Hall, Ithaca, NY 14853 (United States)

    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 and implosion phases. X-ray yield was increased with soldered arrays in negative polarity with long pulses. The bolometer also showed a 50% increase in radial power emitted for soldered arrays. 4-frame images showed soldered arrays have a more pronounced 'Christmas Tree' effect originating from the cathode. The inductive voltage monitor showed, with both long and short pulses, that soldered and no-solder arrays reached the same minimum current radius at the same time. However, with long pulses soldered arrays radiate x-rays at the time of minimum current radius while no-solder array x-ray output is delayed by {approx}20 ns, resulting in decreased x-ray yield.

  11. Advanced Space Propulsion Based on the Flow-Stabilized Z-Pinch Fusion Concept

    Microsoft Academic Search

    U. Shumlak; R. C. Lilly; C. S. Adams; R. P. Golingo; S. L. Jackson; S. D. Knecht; B. A. Nelson

    2006-01-01

    A fusion space thruster based on the flow-stabilized Z-pinch may be possible in the near-term and provide many advantages over other fusion-based thruster concepts. The Z- pinch equilibrium is classically unstable to gross disruption modes according to theoretical, numerical, and experimental evidence. However, a new stabilization mechanism has been discovered that can stabilize these modes with plasma flow. The stabilizing

  12. Designs, tests and plans for MAIZE: a 1 MA LTD-driven z-pinch

    Microsoft Academic Search

    R. M. Gilgenbach; M. R. Gomez; J. Zier; W. Tang; B. W. Hoff; N. Jordan; E. Cruz; Y. Y. Lau; M. G. Mazarakis; M. Cuneo; M. D. Johnston; B. V. Oliver; T. A. Mehlhorn; A. A. Kim; V. A. Sinebryukhov

    2008-01-01

    We present designs, resistive-load test results and experimental plans of the first 1 MA z-pinch in the USA to be driven by a Linear Transformer Driver (LTD). The Michigan Accelerator for Inductive Z-pinch Experiments, (MAIZE), is based on the LTD developed at the Institute for High Current Electronics in collaboration with Sandia National Labs. This LTD utilizes 80 capacitors and

  13. Optical Spectroscopy Measurements of Preheat in Z-Pinch Driven Hohlraums

    Microsoft Academic Search

    James E. Bailey

    1998-01-01

    A variety of z-pinch driven hohlraum configurations have been proposed for Inertial Confinement Fusion applications. One concern common to all of them is the possibility of preheat of the fusion capsule by radiation during the Z-Pinch implosion, un-intended current flow through the hohlraum, or high energy charged particles. We describe measurements of the preheat in hohlraums driven by the Z

  14. X-Ray Imaging Measurements of Capsule Implosions Driven by a Z-Pinch Dynamic Hohlraum

    Microsoft Academic Search

    J. E. Bailey; G. A. Chandler; S. A. Slutz; G. R. Bennett; G. Cooper; J. S. Lash; S. Lazier; R. Lemke; T. J. Nash; D. S. Nielsen; T. C. Moore; C. L. Ruiz; D. G. Schroen; R. Smelser; J. Torres; R. A. Vesey

    2002-01-01

    The radiation and shock generated by impact of an annular tungsten Z-pinch plasma on a 10-mm diam 5-mg\\/cc CH2 foam are diagnosed with x-ray imaging and power measurements. The radiative shock was virtually unaffected by Z-pinch plasma instabilities. The 5-ns-duration ~135-eV radiation field imploded a 2.1-mm-diam CH capsule. The measured radiation temperature, shock radius, and capsule radius agreed well with

  15. Magnetoelectric confinement and stabilization of Z pinch in a soft-x-ray Ar(+8) laser.

    PubMed

    Szasz, J; Kiss, M; Santa, I; Szatmari, S; Kukhlevsky, S V

    2013-05-01

    Magnetoelectric confinement and stabilization of the plasma column in a soft-x-ray Ar(+8) laser, which is excited by a capillary Z pinch, via the combined magnetic and electric fields of the gliding surface discharge is experimentally demonstrated. Unlike soft-x-ray lasers excited by the conventional capillary Z pinches, the magnetoelectric confinement and stabilization of plasma do provide the laser operation without using any external preionization circuit. PMID:23683196

  16. Characteristics and scaling of tungsten-wire-array z -pinch implosion dynamics at 20 MA

    Microsoft Academic Search

    M. E. Cuneo; E. M. Waisman; S. V. Lebedev; J. P. Chittenden; W. A. Stygar; G. A. Chandler; R. A. Vesey; E. P. Yu; T. J. Nash; D. E. Bliss; G. S. Sarkisov; T. C. Wagoner; G. R. Bennett; D. B. Sinars; J. L. Porter; W. W. Simpson; L. E. Ruggles; D. F. Wenger; C. J. Garasi; B. V. Oliver; R. A. Aragon; W. E. Fowler; M. C. Hettrick; G. C. Idzorek; D. Johnson; K. Keller; S. E. Lazier; J. S. McGurn; T. A. Mehlhorn; T. Moore; D. S. Nielsen; J. Pyle; S. Speas; K. W. Struve; J. A. Torres

    2005-01-01

    We present observations for 20-MA wire-array z pinches of an extended wire ablation period of 57%±3% of the stagnation time of the array and non-thin-shell implosion trajectories. These experiments were performed with 20-mm-diam wire arrays used for the double- z -pinch inertial confinement fusion experiments [M. E. Cuneo , Phys. Rev. Lett. 88, 215004 (2002)] on the Z accelerator [R.

  17. Effect of Radiation Cooling and Plasma Atomic Number on Z-Pinch Dynamics

    Microsoft Academic Search

    James Edward Bailey

    1984-01-01

    A gas puff z-pinch is operated by injecting a gas annulus into the space between two electrodes, then applying a voltage pulse (supplied by a 5 KJ, 30 KV capacitor bank) to initiate a z-pinch discharge. During the pinched stage, the plasma electron density reaches 10('20)cm(' -3) and T(,e) (DBLTURN) 100 eV. At these parameters, moderate atomic number atoms emit

  18. Analytic model for the dynamic Z-pinch

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

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

    SciTech Connect

    Spielman, R.B.; Breeze, S.F.; Deeney, C. [and others

    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.

  20. 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 implosion time tau(i). For an accelerator coupled to a double-pinch-driven hohlraum that drives the implosion of an ICF fuel capsule, we find that the accelerator power and energy required to achieve high-yield fusion scale as tau(i)0.36 and tau(i)1.36, respectively. Thus the accelerator requirements decrease as the implosion time is decreased. However, the x-ray-power and thermonuclear-yield efficiencies of such a coupled system increase with tau(i). We also find that increasing the anode-cathode gap of the pinch from 2 to 4 mm increases the requisite values of P(a) and E(a) by as much as a factor of 2. PMID:16196715

  1. 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.

  2. Experimental investigation of phase explosion by irradiating thin aluminum targets with high power pulsed laser beam

    NASA Astrophysics Data System (ADS)

    Mahdieh, M. H.; Akbari Jafarabadi, M.; Firozyar, Sh.; Hajiani, Sh.

    2012-01-01

    In this paper phase explosion in aluminum targets induced by Nd:YAG pulsed laser beam is studied. The phase explosion occurs in ablation process when the Nd:YAG laser beam (single pulse) is focused on the surface of target in ambient air. The phase explosion was investigated by monitoring the transmission of a cw laser probe beam through the ablating region. Two different aluminum targets were used in this study; a thin film aluminum on a quartz substrate, and a thick aluminum foil. The results show that the probe beam transmission through the ablated region is enhanced significantly when the laser fluence is enough for the phase explosion to be occurred.

  3. Axial x-ray backlighting of wire-array Z-pinches using X pinches.

    PubMed

    Blesener, I C; Greenly, J B; Pikuz, S A; Shelkovenko, T A; Vishniakou, S; Hammer, D A; Kusse, B R

    2009-12-01

    For the first time, a geometry has been developed to allow for an axial imaging system for wire-array Z-pinch experiments that produce high-resolution x-ray images. The new geometry required a significant redesign of the electrode hardware. Calibrated areal density measurements of the Z-pinch plasma including wire cores, coronal plasma, streaming plasma, and the precursor were obtained. The system used eight-wire molybdenum (Mo) X pinches in series with and directly below the Z-pinch axis to provide micron-scale x-rays sources for point-projection radiography. The images formed on the x-ray sensitive film had a 15 mm diameter field of view at the center height of the array and a magnification of about 7.5:1. Titanium (Ti) filters in front of the film transmitted radiation in the spectral range of 3-5 keV. For calibration, a separate film with the same thickness Ti filter was placed the same distance from the X pinch. This film had an unobstructed path that bypasses the Z-pinch but included step wedges for calibration of the Z-pinch plasma. The step wedges had thicknesses of tungsten (W) ranging from 0.015 to 1.1 microm to obtain areal density measurements of the W plasma from the wire-array. Images had subnanosecond temporal resolution and about 10 microm spatial resolution. PMID:20059143

  4. Insights and Applications of 2-D Simulations to Z-Pinch Experiments

    NASA Astrophysics Data System (ADS)

    Peterson, Darrell L.

    1998-11-01

    A two-dimensional (2-D) Eulerian radiation-magnetohydrodynamic code has been used to successfully simulate z-pinch experiments fielded on several facilities with a wide variety of drive conditions, timescales and loads.(Peterson, et al, Phys. Plasmas) 3, 368 (1996); Matuska, et al, Phys. Plasmas 3, 1415 (1996); and Peterson, et al, Phys. Plasmas to be published Sept. 1998 The 2-D simulations of these experiments reproduce important quantities of interest including the radiation pulse energy, power and pulsewidth. To obtain this agreement a variable parameter, the level of random density perturbations imposed early in the implosion, is adjusted which then seeds the development of magnetically driven Rayleigh-Taylor instabilities. The instabilities greatly affect the dynamics of the implosion and the resulting production of radiation. Analysis of such simulations allows insights into the physical processes by which these calculations reproduce the experimental results. As an example, simulations of Sandia ``Z'' accelerator experiments have shown a short-wavelength growth phase, saturation after breaking through the plasma shell, followed by longer wavelength development. This effect seems to be responsible in the simulations for the survival of the imploding plasma shell as a coherent entity, and the resultant high quality of the radiation pulse. At the same time, the thickened shell allows for an extended time period of energy deposition by the Lorentz force into the plasma which then accounts for the high energy yields. As another example, the insights gained from the simulations have allowed for investigation of possible physical processes which produce high powers in ``nested array'' implosions and high temperatures within ``dynamic hohlraum'' loads. Building on these insights, the 2-D code has been used in designing new experiments to optimize the desired physical conditions and in interpreting the experimental results obtained. These examples and others will be discussed as well as examples of simulation results where improvement is needed and what steps are being taken to make that improvement.

  5. Investigation of the role of ion stopping power in Z-pinch stagnation physics

    NASA Astrophysics Data System (ADS)

    Mehlhorn, Thomas; Giuliani, John; Thornhill, Ward; Maron, Yitzhak

    2013-10-01

    A recent paper shows that for Z-pinches implosions optimized to produce K-shell radiation, the stagnating plasma pressure is balanced by the implosion pressure and the radiation energy is provided by the implosion kinetic energy. This result is valid for both neon gas-puff loads at the Weizmann Institute (500 kA, 500 ns) and for nested aluminum-titanium wire arrays on Sandia's Z-machine (20 MA, 100 ns). Multi-frame pinhole photography and spectroscopic analysis of the neon gas puff shows the radius of the stagnation plasma increasing from r = 0.2 mm to r = 0.45 mm in 3.5 ns and that the density is nearly constant during the K-shell emission period. Table I in Ref. 1 lists the implosion velocity as 2.3e7 cm/s, Z-bar = 8.7, Te = 0.2 keV, and ni = 6e19/cc for the Weizmann gas puff. A very similar phenomenology is observed for Sandia's imploding wire arrays with radius growing from 0.6 to 2.1 mm in 6 ns with an implosion velocity = 7e7 cm/s resulting in stagnation plasmas with Zbar = 14.1, Te = 2.5 keV and ni = 3.5e19/cc. In this presentation we will study what role the kinetic energy loss of the imploding ions in the stagnation plasma may play in determining the initial scale, density, and evolution of these plasmas. A recent paper shows that for Z-pinches implosions optimized to produce K-shell radiation, the stagnating plasma pressure is balanced by the implosion pressure and the radiation energy is provided by the implosion kinetic energy. This result is valid for both neon gas-puff loads at the Weizmann Institute (500 kA, 500 ns) and for nested aluminum-titanium wire arrays on Sandia's Z-machine (20 MA, 100 ns). Multi-frame pinhole photography and spectroscopic analysis of the neon gas puff shows the radius of the stagnation plasma increasing from r = 0.2 mm to r = 0.45 mm in 3.5 ns and that the density is nearly constant during the K-shell emission period. Table I in Ref. 1 lists the implosion velocity as 2.3e7 cm/s, Z-bar = 8.7, Te = 0.2 keV, and ni = 6e19/cc for the Weizmann gas puff. A very similar phenomenology is observed for Sandia's imploding wire arrays with radius growing from 0.6 to 2.1 mm in 6 ns with an implosion velocity = 7e7 cm/s resulting in stagnation plasmas with Zbar = 14.1, Te = 2.5 keV and ni = 3.5e19/cc. In this presentation we will study what role the kinetic energy loss of the imploding ions in the stagnation plasma may play in determining the initial scale, density, and evolution of these plasmas. Work supported by DOE/NNSA.

  6. Study of the 3D Structure of the Stagnated Z-Pinch

    NASA Astrophysics Data System (ADS)

    Anderson, Austin; Ivanov, Vladimir

    2014-10-01

    Z pinches are the most powerful laboratory sources of x-ray radiation. Z pinches represent an unstable plasma configuration and are subjected by strong plasma instabilities at the ablation, implosion, and stagnation stages. MHD instability produce necks, kinks, and micropinches at stagnation. Knowledge of the 3D plasma distribution is important for interpreting 2D images of the pinch, as well as understanding the effectiveness of models that assume azimuthal symmetry using Abel inversion. Recent experiments were conducted with 266 nm laser shadowgrams from 4 channels, evenly spaced in 45 degree increments. Channels were timed with 100 ps temporal accuracy to provide simultaneous imaging. Results and discussion on the azimuthal non-uniformity of the Z pinch are presented.

  7. Measurement of temperature, density, and particle transport with localized dopants in wire-array Z pinches.

    PubMed

    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. PMID:18352197

  8. PHYSICAL REVIEW E 84, 056408 (2011) Doppler measurement of implosion velocity in fast Z-pinch x-ray sources

    E-print Network

    Starobinets, Alexander

    2011-01-01

    PHYSICAL REVIEW E 84, 056408 (2011) Doppler measurement of implosion velocity in fast Z-pinch x implosion velocities of up to 70 cm/s in wire-array and gas-puff Z pinches at drive currents of 15­20 MA. These data can benchmark numerical implosion models, which produce reasonable agreement with the measured

  9. On the Vlasov fluid stability of the m = 0 mode in a pure Z pinch

    NASA Astrophysics Data System (ADS)

    Coppins, M.; Bond, D. J.; Haines, M. G.

    1984-08-01

    The possibility of using the Vlasov fluid model to describe large ion Larmor radius effects in a Z pinch is discussed. It is shown that the Vlasov fluid formulation can be applied to the m = 0 mode, but the comparison theorem which states that systems which are MHD stable are also Vlasov fluid stable, is shown to be inapplicable in this case.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    The ZaP-HD flow Z-pinch project investigates scaling the sheared flow Z-pinch to HEDP conditions by using sheared flow stabilization. Z-pinch plasmas have been produced that are 100 cm long with a 1 cm radius and are quiescent for many radial Alfven times and axial flow times. 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, and NIMROD. 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 of density, flow, electron & ion temperature, and magnetic field. Wall stabilization is investigated computationally and experimentally by removing 70% of the surrounding conducting wall. The flow Z-pinch concept provides an approach to achieve HED plasmas, which are large and persist for extended durations. The new experiment, ZaP-HD, has been built to investigate this approach. Experimental results and scaling analyses are presented. This work is supported by grants from US DoE and NNSA.

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

    Microsoft Academic Search

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

    2000-01-01

    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

  12. 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.

  13. 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. PMID:24655260

  14. Feasibility of a nitrogen-recombination soft-x-ray laser using capillary discharge Z pinch.

    PubMed

    Kampel, N S; Rikanati, A; Be'ery, I; Ben-Kish, A; Fisher, A; Ron, A

    2008-11-01

    Capillary discharge Z pinches have been shown to be efficient drivers for x-ray lasers (XRLs). In this work we examine the possibility of realizing a H_{alpha} nitrogen recombination laser ( 3-->2 transition) at lambda=13.4nm , using a capillary discharge Z pinch. A pulsed power generator with 60kA peak current and 70ns quarter period have been used to generate Z -pinch plasma in a 90-mm -long and 5-mm -diameter capillary. The plasma conditions were evaluated experimentally, using a filtered x-ray diode detector and time-integrated spectroscopy. The conditions required for the XRL were analytically estimated based on simple steady-state rate equations and then compared to experimental results. We demonstrated above 10% N7+ abundance at pinch time, while at least 50% is required. Then, in the expansion phase, the plasma is cooled in a time less than 5ns to temperatures below 60eV , as needed for the recombination laser. These results suggest that the required conditions for nitrogen-recombination lasing could be achieved in a capillary discharge Z pinch, but a higher-power driver might be needed. PMID:19113223

  15. Physics of wire array Z-pinch implosions: experiments at Imperial College

    Microsoft Academic Search

    S. V. Lebedev; D. J. Ampleford; S. N. Bland; S. C. Bott; J. P. Chittenden; J. Goyer; C. Jennings; M. G. Haines; G. N. Hall; D. A. Hammer; J. B. A. Palmer; S. A. Pikuz; T. A. Shelkovenko; T. Christoudias

    2005-01-01

    A review of recent experiments on the MAGPIE generator (1 MA, 250 ns) aimed at studying the implosion dynamics of wire array Z-pinches is presented. The first phase of implosion is dominated by the gradual ablation of stationary wire cores and gradual redistribution of the array mass by the precursor plasma flow. It is found that the rate of wire

  16. High yield inertial confinement fusion target design for a {ital z}-pinch-driven hohlraum

    SciTech Connect

    Hammer, J.H.; Tabak, M.; Wilks, S.C.; Lindl, J.D.; Bailey, D.S.; Rambo, P.W.; Toor, A.; Zimmerman, G.B. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Porter, J.L. Jr. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1191 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-1191 (United States)

    1999-05-01

    Calculations are presented for a high yield inertial fusion design, employing indirect drive with a double-ended {ital z}-pinch-driven hohlraum radiation source. A high current ({approximately}60 MA) accelerator implodes {ital z} pinches within an enclosing hohlraum. Radial spoke arrays and shine shields isolate the capsule from the pinch plasma, magnetic field, and direct x-ray shine. Our approach places minimal requirements on {ital z}-pinch uniformity and stability, usually problematic due to magneto-Rayleigh{endash}Taylor instability. Large inhomogeneities of the pinch and spoke array may be present, but the hohlraum adequately smooths the radiation field at the capsule. Simultaneity and reproducibility of the pinch x-ray output to better than 7{percent} are required, however, for good symmetry. Recent experiments suggest a pulse shaping technique, through implosion of a multishell {ital z} pinch. X-ray bursts are calculated and observed to occur at each shell collision. A capsule absorbing 1 MJ of x rays at a peak drive temperature of 210 eV is found to have adequate stability and to produce 400 MJ of yield. A larger capsule absorbs 2 MJ with a yield of 1200 MJ. {copyright} {ital 1999 American Institute of Physics.}

  17. 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.

  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, ?) 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-array plasma acceleration, shock generation and production, hohlraum formation, radiation ablation and fuel compression.

  19. Numerical simulations of annular wire-array z-pinches in (x,y), (r,{theta}), and (r,z) geometries

    SciTech Connect

    Marder, B.M.; Sanford, T.W.L.; Allshouse, G.O.

    1997-12-01

    The Total Immersion PIC (TIP) code has been used in several two-dimensional geometries to understand better the measured dynamics of annular, aluminum wire-array z-pinches. The areas investigated include the formation of the plasma sheath from current-induced individual wire explosions, the effects of wire number and symmetry on the implosion dynamics, and the dependence of the Rayleigh-Taylor instability growth on initial sheath thickness. A qualitative change in the dynamics with increasing wire number was observed, corresponding to a transition between a z-pinch composed of non-merging, self-pinching individual wires, and one characterized by the rapid formation and subsequent implosion of a continuous plasma sheath. A sharp increase in radiated power with increasing wire number has been observed experimentally near this calculated transition. Although two-dimensional codes have correctly simulated observed power pulse durations, there are indications that three dimensional effects are important in understanding the actual mechanism by which these pulse lengths are produced.

  20. 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. PMID:19044418

  1. 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 [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    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.

  2. History of HERMES III diode to z-pinch breakthrough and beyond : learning about pulsed power and z-pinch ICF.

    SciTech Connect

    Sanford, Thomas W. L.

    2013-04-01

    HERMES III and Z are two flagship accelerators of Sandia's 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.

  3. 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. [Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation)] [Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation); Oreshkin, V. I.; Batrakov, A. V. [Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation) [Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation); Tomsk Polytechnic University, Tomsk (Russian Federation); Baksht, R. B. [Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation) [Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation); Tel-Aviv University, Tel Aviv (Israel)

    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)].

  4. Determination of the inductance of imploding wire array Z-pinches using measurements of load voltage

    SciTech Connect

    Burdiak, G. C.; Lebedev, S. V.; Hall, G. N.; Harvey-Thompson, A. J.; Suzuki-Vidal, F.; Swadling, G. F.; Khoory, E.; Pickworth, L.; Bland, S. N.; Grouchy, P. de; Skidmore, J. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom)

    2013-03-15

    The inductance of imploding cylindrical wire array z-pinches has been determined from measurements of load voltage and current. A thorough analysis method is presented that explains how the load voltage of interest is found from raw signals obtained using a resistive voltage divider. This method is applied to voltage data obtained during z-pinch experiments carried out on the MAGPIE facility (1.4 MA, 240 ns rise-time) in order to calculate the load inductance and thereafter the radial trajectory of the effective current sheath during the snowplough implosion. Voltage and current are monitored very close to the load, allowing these calculations to be carried out without the need for circuit modelling. Measurements give a convergence ratio for the current of between 3.1 and 5.7 at stagnation of the pinch.

  5. Use of Z-pinch radiation sources for high-pressure shock wave studies

    SciTech Connect

    Asay, J.R.; Konrad, C.H.; Hall, C.A.; Trott, W.M.; Chandler, G.A.; Fleming, K.J.; Trucano, T.G.

    1998-08-01

    The authors are developing a new shock wave diagnostic using Z pinch sources for high-pressure equation of state (EOS) measurements. Specifically, they are employing VISAR interferometry to measure the particle velocity of shocked materials and fiber optic probes to measure the shock speed. Combination of these measurements will allow absolute EOS data with Z accelerators. This report is a progress report on the development of this new approach to EOS measurements; however, preliminary data obtained with the diagnostics are encouraging. With further development of Z pinch sources, it is envisioned that a variety of EOS and constitutive property measurements can be made. Time-resolved wave profile measurements will then provide a variety of EOS and material property data, such as isentropic EOS, initial compressive strength and shock-induced compressive strength, dynamic tensile strength, kinetics of phase transitions, and surface stability studies.

  6. Radiation characteristics of high repetition rate capillary Z-pinch EUV source

    Microsoft Academic Search

    Y. Teramoto; Hiroto Sato; Kazunori Bessho; Gohta Niimi; Takahiro Shirai; Daiki Yamatani; Tetsu Takemura; Toshio Yokota; Khokan C. Paul; Kiyoyuki Kabuki; K. Miyauchi; M. Ikeuchi; K. Okubo; K. Hotta; M. Yoshioka; K. Toyoda

    2004-01-01

    An extreme ultraviolet (EUV) source as a candidate for a light source in next generation lithography systems has been studied. A xenon capillary Z-pinch source was coupled with an all-solid-state magnetic pulse compression (MPC) generator. In order to evaluate the source performance, radiation characteristics such as radiation energy, spectrum and angular radiation distribution were observed, as well as the energy

  7. Laser-driven hydrodynamic perturbation in an overdense Z-pinch plasma

    Microsoft Academic Search

    J. G. Ackenhusen; D. R. Bach

    1979-01-01

    Holographic interferometry of the interaction of a radially incident intense CO2 laser beam (10 to the 11th W\\/sq cm, 38-nsec FWHM pulse) with an overdense helium Z-pinch plasma (n sub e greater than 10 to the 19th e\\/cu cm, T sub e of about 20 eV, L = 100 microns) has indicated the presence of a laser-driven shock. The radial

  8. X-Ray Lithography and Microscopy Using a Small - Z-Pinch Device

    Microsoft Academic Search

    Irving Norman Weinberg

    1985-01-01

    The demands of the microelectronics industry for high resolution microlithography of integrated circuitry have generated interest in the plasma z-pinch device as an intense soft x-ray source. In addition there is a desire within the scientific community for an inexpensive pulsed source of soft x-rays for microscopy and elemental analysis. This dissertation describes the construction, testing, and application of a

  9. Measurement and analysis of gas-puff density distributions for plasma radiation source z pinches

    Microsoft Academic Search

    D. Mosher; B. V. Weber; B. Moosman; R. J. Commisso; P. Coleman; E. Waisman; H. Sze; Y. Song; D. Parks; P. Steen; J. Levine; B. Failor; A. Fisher

    2001-01-01

    High-sensitivity interferometry measurements of initial density distributions are reviewed for a wide range of gas-puff nozzles used in plasma radiation source (PRS) z-pinch experiments. Accurate gas distributions are required for determining experimental load parameters, modeling implosion dynamics, understanding the radiation properties of the stagnated pinch, and for predicting PRS performance in future experiments. For a number of these nozzles, a

  10. Z-Pinch-Driven Hemispherical Capsule Implosions for Fast Ignitor Fuel Assembly

    Microsoft Academic Search

    D. L. Hanson; R. A. Vesey; D. B. Sinars; M. E. Cuneo; R. G. Adams; S. A. Slutz; J. L. Porter; R. R. Johnston; D. F. Wenger; D. G. Schroen; C. Russell

    2004-01-01

    Rad-hydro simulations indicate that partial-sphere fusion capsules can be compressed to peak densities of interest for fast ignition experiments with the symmetry control available in a single-ended indirect drive vacuum hohlraum configuration. We are presently investigating this approach to fast ignitor fuel assembly using pulsed-power driver technology. Current from the Sandia Z accelerator implodes a single wire-array z-pinch in the

  11. ALEGRA Modeling of Gas Puff Z-Pinch Experiments at the ZR Facility

    Microsoft Academic Search

    C. S. Kueny; C. A. Coverdale; D. G. Flicker; M. Krishnan; P. L. Coleman

    2010-01-01

    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

  12. ZPMHD-a Rep-rated Z-Pinch Power Plant Direct Conversion Concept

    Microsoft Academic Search

    John S. de Groot; El Houssein Alki

    2001-01-01

    We have performed a preliminary conceptual study of ZPMHD, a z-pinch driven IFE power plant with Compact Fusion Advanced Rankine (CFARII) MHD direct conversion [B. G. Logan, Fusion Eng. and Des. 22, 151 (1993)]. We find that a competitive power plant could be built that has a Cost of Electricity (CoE) Å 40 mills\\/kWh for a compact blanket of Lithium

  13. Post-implosion evolution of high-current, radiating Z-pinches

    Microsoft Academic Search

    D. Mosher

    1989-01-01

    High-current, high-atomic-number z-pinches created from the implosion of gas puffs and wire arrays radiate strongly in the XUV to keV regime when the plasma assembles on the axis of symmetry. Here, the development of the pinch following assembly is studied using equilibrium relations and a 1d radial, self-similar code for the dynamics. Likely evolutionary paths are determined in terms of

  14. Identification of the governing parameters of self-organizing structures in z-pinch plasmas

    NASA Astrophysics Data System (ADS)

    Ortiz-Tapia, Arturo; Kubeš, Pavel

    2000-03-01

    Using the S-300 device for wire plasma corona generation and streak, obscure and x-frame cameras for diagnostics, it was possible to determine the values of several parameters inside helical and toroidal structures formed in z-pinch. We concluded that the number of particles in the Debye sphere could be N D <1, which makes evident the non-ideal character of plasmas in the helical tube, allowing for long-range correlations and self-organization.

  15. Wire initiation critical for radiation symmetry in z-pinch-driven dynamic hohlraums.

    PubMed

    Sanford, T W L; Jennings, C A; Rochau, G A; Rosenthal, S E; Sarkisov, G S; Sasorov, P V; Stygar, W A; Bennett, L F; Bliss, D E; Chittenden, J P; Cuneo, M E; Haines, M G; Leeper, R J; Mock, R C; Nash, T J; Peterson, D L

    2007-02-01

    Axial symmetry in x-ray radiation of wire-array z pinches is important for the creation of dynamic hohlraums used to compress inertial-confinement-fusion capsules. We present the first evidence that this symmetry is directly correlated with the magnitude of the negative radial electric field along the wire surface. This field (in turn) is inferred to control the initial energy deposition into the wire cores, as well as any current shorting to the return conductor. PMID:17358953

  16. Hot Dense Capsule-Implosion Cores Produced by Z-Pinch Dynamic Hohlraum Radiation

    Microsoft Academic Search

    J. E. Bailey; G. A. Chandler; S. A. Slutz; I. Golovkin; P. W. Lake; J. J. Macfarlane; R. C. Mancini; T. J. Burris-Mog; G. Cooper; R. J. Leeper; T. A. Mehlhorn; T. C. Moore; T. J. Nash; D. S. Nielsen; C. L. Ruiz; D. G. Schroen; W. A. Varnum

    2004-01-01

    Hot dense capsule implosions driven by Z-pinch xrays have been measured using a ˜220 eV dynamic hohlraum to implode 1.7 2.1mm diameter gas-filled CH capsules. The capsules absorbed up to ˜20 kJ of xrays. Argon tracer atom spectra were used to measure the Te˜1 keV electron temperature and the ne˜1 4×1023 cm-3 electron density. Spectra from multiple directions provide core

  17. High yield inertial fusion design for a z-pinch accelerator

    SciTech Connect

    Hammer, J H; Lindl, J; Porter, J L; Rambo, P W; Tabak, M; Toor, A; Wilks, S; Zimmerman, G B

    1998-10-01

    In this paper we discuss design calculations for high yield inertial fusion capsules, indirectly driven by a double-ended z-pinch-driven hohlraum radiation source. The z-pinches are imploded by a high current (- 60 MA) accelerator while enclosed within a hohlraum. Radial spoke arrays and shine shields isolate the capsule from the pinch plasma, magnetic field and direct x-ray shine. Our approach places minimal requirements on z-pinch uniformity and stability, usually problematic due to magneto- Rayleigh Taylor (MRT) instability. The hohlraum smooths the radiation field at the capsule, even in the presence of large millimeter scale inhomogeneities of the pinch and the high-spatial-frequency pertur- bation of the spoke array. The design requires simultaneity and reproducibility of the x-ray output to 5- 10%, however. Reproducibility at this level may be achievable based on experience with the Z and Sat- urn accelerators. Recent Z experiments also suggest a method for generating the required x-ray pulse shape, through implosion of a multi-shell z-pinch. X-ray bursts are calculated and observed to occur at each shell collision. Variation of shell masses and radii allows considerable latitude for creating the desired pulse shape. For the design considered, a capsule absorbing 1 MJ of x-rays at a peak drive tem- perature of 210 eV is found to have adequate stability and produces 400 MJ of yield. A larger capsule with slightly longer drive and similar peak temperature absorbs 2 MJ with a yield of 1200 MJ.

  18. Three-dimensional effects in trailing mass in the wire-array Z pinch

    Microsoft Academic Search

    Edmund P. Yu; M. E. Cuneo; M. P. Desjarlais; R. W. Lemke; D. B. Sinars; T. A. Haill; E. M. Waisman; G. R. Bennett; C. A. Jennings; T. A. Mehlhorn; T. A. Brunner; H. L. Hanshaw; J. L. Porter; W. A. Stygar; L. I. Rudakov

    2008-01-01

    The implosion phase of a wire-array Z pinch is investigated using three-dimensional (3D) simulations, which model the mass ablation phase and its associated axial instability using a mass injection boundary condition. The physical mechanisms driving the trailing mass network are explored, and it is found that in 3D the current paths though the trailing mass can reduce bubble growth on

  19. X-ray imaging measurements of capsule implosions driven by a z-pinch dynamic hohlraum

    Microsoft Academic Search

    J. E. Bailey; G. A. Chandler; G. Cooper; D. E. Hebron; J. S. Lash; R. W. Lemke; J. McGurn; T. J. Nash; C. L. Ruiz; S. A. Slutz; J. Torres; W. Varnum; R. A. Vesey; G. R. Bennett; D. O. Jobe; P. Lake; S. Lazier; T. C. Moore; D. S. Nielson; Smelser; D. G. Schroen; J. J. Macfarlane

    2001-01-01

    We report on the first time-resolved measurements of an imploding capsule radius driven by radiation within a z-pinch dynamic hohlraum (ZPDH). The configuration uses a gas-filled 2-mm-diameter CH capsule embedded in a cylindrical CH foam. The pinch plasma impact with the foam creates radiation that drives the capsule. The radiation is measured with a filtered XRD array and the capsule

  20. Comparison Between Laser Initiated Hollow Gas Embedded Z-pinches with Different Initial Radius

    Microsoft Academic Search

    Felipe Veloso; Hernán Chuaqui; Raúl Aliaga-Rossel; Mario Favre; Ian Mitchell; Edmund Wyndham

    2006-01-01

    An experimental study of the effect of the initial radius on the formation of hollow gas embedded z-pinches is presented. These hollow pinches are formed using a ring precursor plasma generated by focussing a 10ns, 0.2J, 1064nm, Nd:YAG laser pulse onto the cathode surface. The laser pulse is focussed into a ring shape, by using a combination of a converging

  1. Generation and anisotropy of neutron emission from a condensed Z-pinch

    NASA Astrophysics Data System (ADS)

    Bakshaev, Yu. L.; Bryzgunov, V. A.; Vikhrev, V. V.; Volobuev, I. V.; Dan'ko, S. A.; Kazakov, E. D.; Korolev, V. D.; Klír, D.; Mironenko-Marenkov, A. D.; Pimenov, V. G.; Smirnova, E. A.; Ustroev, G. I.

    2014-06-01

    The paper presents results of measurements of neutron emission generated in the constriction of a fast Z-pinch at the S-300 facility (2 MA, 100 ns). An increased energy concentration was achieved by using a combined load the central part of which was a microporous deuterated polyethylene neck with a mass density of 100 mg/cm3 and diameter of 1-1.5 mm. The neck was placed between two 5-mm-diameter agar-agar cylinders. The characteristics of neutron emission in two axial and two radial directions were measured by the time-of-flight method. The neutron spectrum was recovered from the measured neutron signals by the Monte Carlo method. In all experiments, the spatiotemporal characteristics of plasma in the Z-pinch constriction were measured by means of the diagnostic complex of the S-300 facility, which includes frame photography in the optical, VUV, and soft X-ray (SXR) spectral regions; optical streak imaging; SXR detection; and time-integrated SXR photography. The formation of hot dense plasma in the Z-pinch constriction was accompanied by the generation of hard X-ray (with photon energies E > 30 keV), SXR (with photon energies E > 1 keV and duration of 2-4 ns), and neutron emission. Anisotropy of the neutron energy distribution in the axial direction was revealed. The mean neutron energies measured in four directions at angles of 0° (above the anode), 90°, 180° (under the cathode), and 270° with respect to the load axis were found to be of 2.1 ± 0.1, 2.5 ± 0.1, 2.6 ± 0.2, and 2.4 ± 0.1 MeV, respectively. For a 1-mm-diameter neck, the maximum integral neutron yield was 6 × 109 neutrons. The anisotropy of neutron emission for a Z-pinch with a power-law distribution of high-energy ions is calculated.

  2. MHD simulation of deuterium-fiber-initiated Z-pinches with two-fluid effects

    SciTech Connect

    Sheehey, P. [California Univ., Los Angeles, CA (United States). Dept. of Physics; Lindemuth, I.R. [Los Alamos National Lab., NM (United States)

    1993-05-01

    Two-dimensional ``cold-start`` resistive MHD computations of formation and evolution of deuterium-fiber-initiated Z-pinches have been extended to include separate ion and electron energy equations and finite-Larmor-radius ordered terms. In the Ohm`s Law (magnetic field evolution) equation, Hall and diamagnetic pressure terms have been added, and corresponding terms have been added to the energy equations. Comparison is made of the results of these computations with previous computations and with experiments.

  3. MHD simulation of deuterium-fiber-initiated Z-pinches with two-fluid effects

    SciTech Connect

    Sheehey, P. (California Univ., Los Angeles, CA (United States). Dept. of Physics); Lindemuth, I.R. (Los Alamos National Lab., NM (United States))

    1993-01-01

    Two-dimensional cold-start'' resistive MHD computations of formation and evolution of deuterium-fiber-initiated Z-pinches have been extended to include separate ion and electron energy equations and finite-Larmor-radius ordered terms. In the Ohm's Law (magnetic field evolution) equation, Hall and diamagnetic pressure terms have been added, and corresponding terms have been added to the energy equations. Comparison is made of the results of these computations with previous computations and with experiments.

  4. A conceptual fusion reactor based on the high-plasma-density Z-pinch

    Microsoft Academic Search

    C. W. Hartman; G. Carlson; M. Hoffman; R. Werner; D. Y. Cheng

    1977-01-01

    Conceptual DT and DD fusion reactors are discussed based on magnetic confinement with the high-plasma-density Z-pinch. The reactor concepts have no 'first wall', the fusion neutrons and plasma energy being absorbed directly into a surrounding lithium vortex blanket. Efficient systems with low recirculated power are projected, based on a flow-through pinch cycle for which overall Q values can approach 10.

  5. A New High Current Fast 100ns LTD Based Driver for Z-pinch IFE at Sandia

    Microsoft Academic Search

    M. G. Mazarakis; C. L. Olson

    2005-01-01

    Sandia is actively pursuing the development of new accelerators based on the novice technology of linear transformer driver (LTD). LTD based drivers are currently considered for many applications including future very high current Z-pinch drivers like ZX and z-pinch IFE (inertial fusion energy). LTD is a new method for constructing high-current, high-voltage pulsed accelerators. The salient feature of the approach

  6. The Physics of the Dense Z-Pinch in Theory and in Experiment With Application to Fusion Reactor

    Microsoft Academic Search

    M G Haines

    1982-01-01

    A new generation of Z-pinches employing high voltage, high current pulsed lines as power sources produce dense hot plasmas with enhanced stability properties. Three methods of Z-pinch formation are currently in use: (1) cylindrical collapse and compression of a pre-ionised gas; (2) laser initiation and Joule heating of a gas embedded pinch, and (3) hollow gas puff and subsequent collapse

  7. Characteristics for the occurrence of a high-current, Z-pinch aurora as recorded in antiquity

    Microsoft Academic Search

    Anthony L. Peratt

    2003-01-01

    The discovery that objects from the Neolithic or Early Bronze Age carry patterns associated with high-current Z-pinches provides a possible insight into the origin and meaning of these ancient symbols produced by man. This paper directly compares the graphical and radiation data from high-current Z-pinches to these patterns. The paper focuses primarily, but not exclusively, on petroglyphs. It is found

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

    PubMed

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

    2011-10-01

    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. PMID:22181284

  9. 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. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)] [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Chittenden, J. P.; Niasse, N. [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)] [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Pikuz, S. A.; Shelkovenko, T. A. [P.N. Lebedev Physical Institute, Moscow 119991 (Russian Federation)] [P.N. Lebedev Physical Institute, Moscow 119991 (Russian Federation)

    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.

  10. Radiative cooling of two-component wire-array Z-pinch plasma

    SciTech Connect

    Ivanov, V. V.; Mancini, R. C.; Papp, D.; Hakel, P.; Durmaz, T. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Florido, R. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Departamento de Física, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria (Spain)

    2014-08-15

    Wire-array two-component Z-pinch plasmas containing Al and other elements were studied experimentally and the observations interpreted with the help of theoretical modeling. Special attention was given to achieving reproducible implosions. Cascading implosions in star wire arrays mix components during the implosion phase and implosion dynamics were not affected by changes in concentration. A reduction in Al K-shell radiation and an increase in soft x-ray radiation emission were observed in Al-W plasma with 84% concentration of Al ions compared to only-Al plasma. Plasma with 84% of Al ions has radiative properties like those of W Z-pinches. The analysis of Al K-shell x-ray spectra with a collisional-radiative atomic kinetics model shows a drop of the electron temperature from 400?eV in pure Al plasma to below 300?eV in the Al-W mix. Al-Au Z-pinches present radiation features similar to Al-W plasma. This is indicative of a similar plasma cooling effect due to the presence of a high-Z element.

  11. 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.

  12. Grazing incidence extreme ultraviolet spectrometer fielded with time resolution in a hostile z-pinch environment.

    PubMed

    Williamson, K M; Kantsyrev, V L; Safronova, A S; Wilcox, P G; Cline, W; Batie, S; LeGalloudec, B; Nalajala, V; Astanovitsky, A

    2011-09-01

    This recently developed diagnostic was designed to allow for time-gated spectroscopic study of the EUV radiation (4 nm < ? < 15 nm) present during harsh wire array z-pinch implosions. The spectrometer utilizes a 25 ?m slit, an array of 3 spherical blazed gratings at grazing incidence, and a microchannel plate (MCP) detector placed in an off-Rowland position. Each grating is positioned such that its diffracted radiation is cast over two of the six total independently timed frames of the MCP. The off-Rowland configuration allows for a much greater spectral density on the imaging plate but only focuses at one wavelength per grating. The focal wavelengths are chosen for their diagnostic significance. Testing was conducted at the Zebra pulsed-power generator (1 MA, 100 ns risetime) at the University of Nevada, Reno on a series of wire array z-pinch loads. Within this harsh z-pinch environment, radiation yields routinely exceed 20 kJ in the EUV and soft x-ray. There are also strong mechanical shocks, high velocity debris, sudden vacuum changes during operation, energic ion beams, and hard x-ray radiation in excess of 50 keV. The spectra obtained from the precursor plasma of an Al double planar wire array contained lines of Al IX and AlX ions indicating a temperature near 60 eV during precursor formation. Detailed results will be presented showing the fielding specifications and the techniques used to extract important plasma parameters using this spectrometer. PMID:21974586

  13. X-ray Spectroscopy of K- and L-shell Z-pinch and Astrophysical Plasmas

    SciTech Connect

    Dasgupta, A.; Davis, J.; Giuliani, J. G. [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States); Clark, R. W. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States)

    2009-09-10

    In recent years, there have been significant advances in instrumental capabilities for making X-ray spectroscopic measurements of astrophysical plasmas. There have been corresponding improvements in X-ray diagnostics for advanced multi-mega-ampere pulse power machines that produce increasingly large radiative yields from gas-puff and wire array Z pinch plasmas. Analysis used for Z pinches can be used to study ICF and also astrophysical plasmas where laboratory measurements and simulations are the only means to interpret observed data. The astrophysical data for Fe, the most cosmically abundant high Z element, can provide a wealth of information about cosmic plasmas. Fe is also the key element in stainless steel (SS) wire arrays that are investigated as an intense X-ray radiation source at the Z machine at Sandia National Laboratories. The implosion dynamics of an array of wires on the Z and/or refurbished Z accelerator produces an abundance of radiation from the K- and L-shell ionization stages. These dynamic plasmas are inherently non-LTE, with opacity and other factors influencing the X-ray output. As the plasma assembles on axis, a number of time resolved snapshots provide temperature and density profiles and map the emitting region. We will analyze the ionization dynamics and generate K- and L-shell spectra using the conditions generated in the Z and/or refurbished Z accelerator, described by a 1-D non-LTE radiation-hydrodynamics model. Diagnostics based on spectral shape of L-shell emissions are inherently more difficult than those based on K-shell emissions because of more complex multiplet structures and line overlaps. The non-LTE populations are obtained by using detailed atomic models that include all important excitation, ionization, and recombination processes. We will highlight the connection between laboratory Z-pinch plasma simulations and astrophysical plasmas.

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

    SciTech Connect

    Chang, T.; Fisher, A.; Van Drie, A. (Department of Physics, University of California, Irvine, California 92717 (US))

    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.

  15. 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. 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.

  16. Study of the stability of the Z pinch under fusion conditions using the Hall fluid model

    SciTech Connect

    Coppins, M.; Bond, D.J.; Haines, M.G.

    1984-12-01

    The Hall fluid model (a quasineutral two-fluid model with T/sub e/ = 0) is used to investigate the effect of the Hall term on the m = 0 instability in a pure Z pinch. The problem is treated numerically by a linearized initial value code. Two different equilibria are investigated. The growth rate of the fastest growing magnetohydrodynamic mode is increased for one equilibrium and reduced for the other by the inclusion of the Hall term, and in the second case new modes with high growth rates are found. The possibility of Hall term destabilization of MHD stable equilibria is suggested.

  17. 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. [Laboratory of Plasma Studies, Cornell University, 369 Upson Hall, Ithaca, New York 14853 (United States); Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

    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.

  18. Fully kinetic particle-in-cell simulations of a deuterium gas puff z pinch.

    PubMed

    Welch, D R; Rose, D V; Clark, R E; Mostrom, C B; Stygar, W A; Leeper, R J

    2009-12-18

    We present the first fully kinetic, collisional, and electromagnetic simulations of the complete time evolution of a deuterium gas puff z pinch. Recent experiments with 15-MA current pinches have suggested that the dominant neutron-production mechanism is thermonuclear. We observe distinct differences between the kinetic and magnetohydrodynamic simulations in the pinch evolution with the kinetic simulations producing both thermonuclear and beam-target neutrons. The kinetic approach demonstrated in this Letter represents a viable alternative for performing future plasma physics calculations. PMID:20366259

  19. High energy density z-pinch plasma conditions with picosecond time resolution.

    PubMed

    Pikuz, S A; Sinars, D B; Shelkovenko, T A; Chandler, K M; Hammer, D A; Ivanenkov, G V; Stepniewski, W; Skobelev, I Yu

    2002-07-15

    Using an X-pinch configuration, we have determined that micropinches produced by exploding-wire z pinches can have densities approaching solid density and temperatures of 0.5-1.8 keV, depending upon the wire material used. These plasma parameters, determined from x-ray spectra recorded using an x-ray streak camera, vary drastically on time scales ranging from <10 to 100 ps. Computer simulations require radiation loss to reproduce the observed plasma implosion, suggesting that a radiative-collapse hypothesis for micropinch plasma formation may be correct. PMID:12144399

  20. Radiation energetics of ICF-relevant wire-array Z pinches.

    PubMed

    Sinars, D B; Lemke, R W; Cuneo, M E; Lebedev, S V; Waisman, E M; Stygar, W A; Jones, B; Jones, M C; Yu, E P; Porter, J L; Wenger, D F

    2008-04-11

    Short-implosion-time 20-mm diameter, 300-wire tungsten arrays maintain high peak x-ray powers despite a reduction in peak current from 19 to 13 MA. The main radiation pulse on tests with a 1-mm on-axis rod may be explained by the observable j x B work done during the implosion, but bare-axis tests require sub-mm convergence of the magnetic field not seen except perhaps in >1 keV emission. The data include the first measurement of the imploding mass density profile of a wire-array Z pinch that further constrains simulation models. PMID:18518042

  1. Effect of radial-electric-field polarity on wire-array Z-pinch dynamics.

    PubMed

    Bland, S N; Lebedev, S V; Chittenden, J P; Ampleford, D J; Bott, S C; Gómez, J A; Haines, M G; Hall, G N; Hammer, D A; Mitchell, I H; Palmer, J B A

    2005-09-23

    The formation of plasma in wire-array Z-pinch experiments was found to depend upon the polarity of the radial-electric field near the wires. Reversing the radial-electric field midway along the length of an array resulted in the ablation rate of one-half of the array being reduced by 50%, significantly delaying the start of its implosion and altering its acceleration towards the axis. The observed phenomena cannot be explained by the standard magnetohydrodynamic models of array behavior, suggesting that effects such as electron emission may be important, especially during wire initiation. PMID:16197143

  2. Demonstration of radiation symmetry control for inertial confinement fusion in double Z-pinch hohlraums.

    PubMed

    Vesey, R A; Cuneo, M E; Bennett, G R; Porter, J L; Adams, R G; Aragon, R A; Rambo, P K; Ruggles, L E; Simpson, W W; Smith, I C

    2003-01-24

    Simulations of a double Z-pinch hohlraum, relevant to the high-yield inertial-confinement-fusion concept, predict that through geometry design the time-integrated P2 Legendre mode drive asymmetry can be systematically controlled from positive to negative coefficient values. Studying capsule elongation, recent experiments on Z confirm such control by varying the secondary hohlraum length. Since the experimental trend and optimum length are correctly modeled, confidence is gained in the simulation tools; the same tools predict capsule drive uniformity sufficient for high-yield fusion ignition. PMID:12570498

  3. Time-resolved voltage measurements of Z-pinch radiation sources with a vacuum voltmeter.

    PubMed

    Murphy, D P; Allen, R J; Weber, B V; Commisso, R J; Apruzese, J P; Phipps, D G; Mosher, D

    2008-10-01

    A vacuum-voltmeter (VVM) was fielded on the Saturn pulsed power generator during a series of argon gas-puff Z-pinch shots. Time-resolved voltage and separately measured load current are used to determine several dynamic properties as the load implodes, namely, the inductance, L(t), net energy coupled to the load, E(coupled)(t), and the load radius, r(t). The VVM is a two-stage voltage divider, designed to operate at voltages up to 2 MV. The VVM is presently being modified to operate at voltages up to 6 MV for eventual use on the Z generator. PMID:19044468

  4. Doppler measurement of implosion velocity in fast Z-pinch x-ray sources.

    PubMed

    Jones, B; Jennings, C A; Bailey, J E; Rochau, G A; Maron, Y; Coverdale, C A; Yu, E P; Hansen, S B; Ampleford, D J; Lake, P W; Dunham, G; Cuneo, M E; Deeney, C; Fisher, D V; Fisher, V I; Bernshtam, V; Starobinets, A; Weingarten, L

    2011-11-01

    The observation of Doppler splitting in K-shell x-ray lines emitted from optically thin dopants is used to infer implosion velocities of up to 70 cm/?s in wire-array and gas-puff Z pinches at drive currents of 15-20 MA. These data can benchmark numerical implosion models, which produce reasonable agreement with the measured velocity in the emitting region. Doppler splitting is obscured in lines with strong opacity, but red-shifted absorption produced by the cooler halo of material backlit by the hot core assembling on axis can be used to diagnose velocity in the trailing mass. PMID:22181529

  5. Modeling nonlinear Rayleigh-Tayor instabilities in fast z-pinches

    SciTech Connect

    Miles, A R

    2008-09-16

    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 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. Characteristics of ICF Relevant Hohlraums Driven by X-Rays from a Z-Pinch

    SciTech Connect

    BOWERS,R.L.; CHANDLER,GORDON A.; HEBRON,DAVID E.; LEEPER,RAMON J.; MATUSKA,W.; MOCK,RAYMOND CECIL; NASH,THOMAS J.; OLSON,RICHARD E.; PETERSON,D.L.; PETERSON,R.R.; RUGGLES,LAURENCE E.; RUIZ,CARLOS L.; SANFORD,THOMAS W. L.; SIMPSON,WALTER W.; VESEY,ROGER A.

    1999-11-03

    Radiation environments characteristic of those encountered during the low-temperature foot pulse and subsequent higher-temperature early-step pulses (without the foot pulse) required for indirect-drive ICF ignition on the National ignition Facility have been produced in hohlraums driven by x-rays from a z-pinch. These environments provide a platform to better understand the dynamics of full-scale NIF hohlraums, ablator material, and capsules prior to NIF completion. Radiation temperature, plasma fill, and wall motion of these hohlraums are discussed.

  7. Effect of Radiation Cooling and Plasma Atomic Number on Z-Pinch Dynamics.

    NASA Astrophysics Data System (ADS)

    Bailey, James Edward

    A gas puff z-pinch is operated by injecting a gas annulus into the space between two electrodes, then applying a voltage pulse (supplied by a 5 KJ, 30 KV capacitor bank) to initiate a z-pinch discharge. During the pinched stage, the plasma electron density reaches 10('20)cm(' -3) and T(,e) (DBLTURN) 100 eV. At these parameters, moderate atomic number atoms emit large amounts of line radiation, primarily in the ultra-soft (10 eV < h(nu) < 1 KeV) x-ray region. The time-resolved x-ray emission was measured with an x-ray diode array. The energy radiated is typically 250 J. The integrated radiation power exceeds 5 GW, which is comparable to the rate at which the magnetic field does work on the plasma. This has led us to study the influence of radiation emission on the pinch dynamics. We have also studied the relation between the dynamics and the atomic number of the working gas. The evolution of the plasma density in space and time was determined with a mach-Zehnder interferometer. The gases studied were hydrogen, deuterium, helium, argon, krypton, deuterium-argon mixtures, and helium -krypton mixtures. The radiation from helium was negligible. The addition of 1.5% krypton to the helium plasma increased the radiation power to 3 GW. The spectrum from the He -Kr mixtures was harder (i.e., the number of higher energy photons increased) than the spectrum from krypton. This could be important for application of the z-pinch as a radiation source. The minimum radius reached by the 98.5% He-1.5% Kr mixture was 0.06 cm, compared to 0.14 cm for helium. Thus, the density increased by a factor of five. The main effect of radiative energy loss is to cool the plasma during the compression, so that a smaller radius and higher density are reached before the plasma pressure balances the magnetic pressure. Some of the gas mixtures resulted in a separation of the annulus into two concentric hollow shells. The lower-Z atoms run in towards the axis ahead of the higher-Z atoms. These results show that both radiation and collisions must be included in an accurate model of z-pinch dynamics.

  8. 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. [Laboratory of Plasma Studies, Cornell University, 439 Rhodes Hall, Ithaca, New York 14853 (United States)

    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.

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

    SciTech Connect

    Baksht, Rina B. [Institutes of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation) [Institutes of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation); Tel-Aviv University, Tel Aviv (Israel); Oreshkin, Vladimir I. [Institutes of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation) [Institutes of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation); Tomsk Polytechnic University, Tomsk (Russian Federation); Rousskikh, Alexander G. [Institutes of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation)] [Institutes of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, Tomsk (Russian Federation)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

    2014-12-01

    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 ?m 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˜5×107 cm/s and the radial convergence ratio is between 10 and 20.

  11. Analysis of spatially resolved Z-pinch spectra to investigate the nature of ``bright spots''

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    Localized, intensely radiating regions are often observed in Z pinches. High resolution images of such areas have been recorded at least as far back as the 1970s. However, there is as yet no widely accepted consensus on the nature of these "bright spots" or how they are formed. This phenomenon has also been referred to "hot spots" or "micropinches." To shed further light on this issue, we have analyzed axially resolved K-shell spectra from 4 Z pinches driven by the refurbished Z generator ("ZR") at Sandia National Laboratories, and the previous version of the Z machine ("Z"). The atomic numbers of the loads varied from 13 to 29. We find that higher spatial K-shell intensity in the Al pinch correlates with density. The K-shell intensity within a copper shot taken on ZR correlates strongly with increased electron temperature, but another, somewhat less well-diagnosed copper shot from Z shows correlation with density. The bright spots in a Ti pinch correlate with neither density nor temperature, but do correlate with the product of density and diameter (proportional to opacity). This opacity correlation is also observed in the other 3 pinches.

  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. Three-dimensional electromagnetic model of the pulsed-power Z-pinch accelerator

    NASA Astrophysics Data System (ADS)

    Rose, D. V.; Welch, D. R.; Madrid, E. A.; Miller, C. L.; Clark, R. E.; Stygar, W. A.; Savage, M. E.; Rochau, G. A.; Bailey, J. E.; Nash, T. J.; Sceiford, M. E.; Struve, K. W.; Corcoran, P. A.; Whitney, B. A.

    2010-01-01

    A three-dimensional, fully electromagnetic model of the principal pulsed-power components of the 26-MA ZR accelerator [D. H. McDaniel , in Proceedings of the 5th International Conference on Dense Z-Pinches (AIP, New York, 2002), p. 23] has been developed. This large-scale simulation model tracks the evolution of electromagnetic waves through the accelerator’s intermediate-storage capacitors, laser-triggered gas switches, pulse-forming lines, water switches, triplate transmission lines, and water convolute to the vacuum insulator stack. The insulator-stack electrodes are coupled to a transmission-line circuit model of the four-level magnetically insulated vacuum-transmission-line section and double-post-hole convolute. The vacuum-section circuit model is terminated by a one-dimensional self-consistent dynamic model of an imploding z-pinch load. The simulation results are compared with electrical measurements made throughout the ZR accelerator, and are in good agreement with the data, especially for times until peak load power. This modeling effort demonstrates that 3D electromagnetic models of large-scale, multiple-module, pulsed-power accelerators are now computationally tractable. This, in turn, presents new opportunities for simulating the operation of existing pulsed-power systems used in a variety of high-energy-density-physics and radiographic applications, as well as even higher-power next-generation accelerators before they are constructed.

  14. Comparison Between Laser Initiated Hollow Gas Embedded Z-pinches with Different Initial Radius

    SciTech Connect

    Veloso, Felipe; Chuaqui, Hernan; Aliaga-Rossel, Raul; Favre, Mario; Mitchell, Ian; Wyndham, Edmund [Departamento de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

    2006-12-04

    An experimental study of the effect of the initial radius on the formation of hollow gas embedded z-pinches is presented. These hollow pinches are formed using a ring precursor plasma generated by focussing a 10ns, 0.2J, 1064nm, Nd:YAG laser pulse onto the cathode surface. The laser pulse is focussed into a ring shape, by using a combination of a converging lens and an axicon. Ring radius variation give place to different initial radius of hollow z-pinches. The experiments were carried out on the Gepopu generator at 110kA, 50ns rise time using flat electrodes. The anode had a central hole, allowing the laser to be focussed onto the cathode surface. Experiments were performed in hydrogen at 1/3 of atmosphere. Schlieren and interferometry are the main plasma diagnostics using the second harmonic of the same laser. Comparison between initial radius of 2 and 3mm are presented, where electron densities on the order of 1018 cm-3 were measured in both cases. Temperature estimates using Bennett relation are of 185 eV and 75 eV respectively. Pinch effect was observed for current density {approx} 5MA/cm2.

  15. Comparison Between Laser Initiated Hollow Gas Embedded Z-pinches with Different Initial Radius

    NASA Astrophysics Data System (ADS)

    Veloso, Felipe; Chuaqui, Hernán; Aliaga-Rossel, Raúl; Favre, Mario; Mitchell, Ian; Wyndham, Edmund

    2006-12-01

    An experimental study of the effect of the initial radius on the formation of hollow gas embedded z-pinches is presented. These hollow pinches are formed using a ring precursor plasma generated by focussing a 10ns, 0.2J, 1064nm, Nd:YAG laser pulse onto the cathode surface. The laser pulse is focussed into a ring shape, by using a combination of a converging lens and an axicon. Ring radius variation give place to different initial radius of hollow z-pinches. The experiments were carried out on the Gepopu generator at 110kA, 50ns rise time using flat electrodes. The anode had a central hole, allowing the laser to be focussed onto the cathode surface. Experiments were performed in hydrogen at 1/3 of atmosphere. Schlieren and interferometry are the main plasma diagnostics using the second harmonic of the same laser. Comparison between initial radius of 2 and 3mm are presented, where electron densities on the order of 1018 cm-3 were measured in both cases. Temperature estimates using Bennett relation are of 185 eV and 75 eV respectively. Pinch effect was observed for current density ˜ 5MA/cm2.

  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. An alternative scaling model for neutron production in Z-pinch devices

    SciTech Connect

    Bures, Brian L.; Krishnan, Mahadevan [Alameda Applied Sciences Corporation, 3077 Teagarden St., San Leandro, California 94577 (United States)

    2012-11-15

    The DD neutron yield (Y{sub n}) from z-pinches, either dense plasma foci or fast radial pinches, has been fitted for decades to the scaling model Y{sub n} {approx} {alpha}(I{sub max}){sup {delta}}, where {alpha} is a numerical scaling coefficient, I{sub max} the peak current, and 3 < {delta} < 5. The data from 12 000 pulses analyzed from eight different z-pinches presented in this paper show that Y{sub n} varies by as much as {+-}15 000% about the best fit value of the conventional scaling model with {delta} = 4. A revised scaling model derived from the reaction rate equation and a circuit model that includes the time derivative of the current dI/dt (normalized to its initial value) reduces the scatter in data from {+-}15 000% to {+-}100%. For the special case of very high normalized dI/dt, the standard deviation between the revised scaling prediction and the measured neutron yields is reduced to just {+-}30%. Implications of this revised scaling for higher current pinches are discussed.

  18. 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.

  19. 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, configuration, and materials of the nozzle must meet many severe requirements. The configuration would focus, in a conical manner, the Deuterium-Tritium (D-T) fuel and Lithium-6/7 liner fluid to meet at a specific point that acts as a cathode so the Li-6 can serve as a current return path to complete the circuit. In addition to serving as a current return path, the Li liner also serves as a radiation shield. The advantage to this configuration is the reaction between neutrons and Li-6 results in the production of additional Tritium, thus adding further fuel to the fusion reaction and boosting the energy output. To understand the applicability of Z-Pinch propulsion to interplanetary travel, it is necessary to design a concept vehicle that uses it. The propulsion system significantly impacts the design of the electrical, thermal control, avionics, radiation shielding, and structural subsystems of a vehicle. The design reference mission is the transport of crew and cargo to Mars and back, with the intention that the vehicle be reused for other missions. Several aspects of this vehicle are based on a previous crewed fusion vehicle study called Human Outer Planet Exploration (HOPE), which employed a Magnetized Target Fusion (MTF) propulsion concept. Analysis of this propulsion system concludes that a 40-fold increase of Isp over chemical propulsion is predicted. This along with a greater than 30% predicted payload mass fraction certainly warrants further development of enabling technologies. The vehicle is designed for multiple interplanetary missions and conceivably may be suited for an automated one-way interstellar voyage.

  20. Effects of mass ablation on the scaling of X-ray power with current in wire-array Z pinches.

    PubMed

    Lemke, R W; Sinars, D B; Waisman, E M; Cuneo, M E; Yu, E P; Haill, T A; Hanshaw, H L; Brunner, T A; Jennings, C A; Stygar, W A; Desjarlais, M P; Mehlhorn, T A; Porter, J L

    2009-01-16

    X-ray production by imploding wire-array Z pinches is studied using radiation magnetohydrodynamics simulation. It is found that the density distribution created by ablating wire material influences both x-ray power production, and how the peak power scales with applied current. For a given array there is an optimum ablation rate that maximizes the peak x-ray power, and produces the strongest scaling of peak power with peak current. This work is consistent with trends in wire-array Z pinch x-ray power scaling experiments on the Z accelerator. PMID:19257285

  1. Visualization of the magnetic field and current path in Z-pinch and X-pinch plasmas

    NASA Astrophysics Data System (ADS)

    Anderson, A. A.; Ivanov, V. V.; Papp, D.

    2015-06-01

    Laser diagnostics at the wavelength of 266 nm allow investigation of wire array Z-pinches and X-pinches at the 1 MA pulse power generator. Faraday rotation diagnostics at 266 nm is applied to study MG magnetic fields in Z-pinch plasma. Faraday diagnostics can qualitatively visualize magnetic fields in dense plasma and give additional information about the current flow even if the plasma density cannot be reconstructed with interferometry. A comparison of images from the three-channel polarimeter shows strong localized magnetic fields, revealing the path for the electric current inside the plasma. Faraday images present current switched to the trailing plasma.

  2. Development of a Flying Coil Valve and Precision Nozzle Throats to Achieve Uniform and Repeatable Cylindrical Gas Puffs for Z-Pinches

    Microsoft Academic Search

    Susan Lee; Kristi Wilson; Alex Bixler; Jason Knight; Anastasia Jarema; John Thompson; Mahadevan Krishnan; Philip Coleman; Ajay Verma

    2005-01-01

    Summary form only given. Z pinches are a well established method to produce pulsed X-rays (plasma radiating sources, PRS). Depending on the application, different spectral contents are desired which means that a range of atomic numbers should be available for use in the Z-pinch load. Gas puff loads complement the capabilities provided by wire array loads, offering the use of

  3. 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.

  4. The study of hard x-ray emission and electron beam generation in wire array Z-pinch and X-pinch plasmas at university-scale generators

    NASA Astrophysics Data System (ADS)

    Shrestha, Ishor Kumar

    The studies of hard x-ray (HXR) emission and electron beam generation in Z-pinch plasmas are very important for Inertial Confinement Fusion (ICF) research and HXR emission application for sources of K-shell and L-shell radiation. Energetic electron beams from Z-pinch plasmas are potentially a problem in the development of ICF. The electron beams and the accompanying HXR emission can preheat the fuel of a thermonuclear target, thereby preventing the fuel compression from reaching densities required for the ignition of a fusion reaction. The photons above 3-4 keV radiated from a Z pinch can provide detailed information about the high energy density plasmas produced at stagnation. Hence, the investigation of characteristics of hard x-rays and electron beams produced during implosions of wire array loads on university scale-generators may provide important data for future ICF, sources of K-shell and L-shell radiations and basic plasma research. This dissertation presents the results of experimental studies of HXR and electron beam generation in wire-array and X-pinch on the 1.7 MA, 100-ns current rise time Zebra generator at University of Nevada, Reno and 1-MA 100-ns current rise-time Cornell Beam Research Accelerator (COBRA) at Cornell University. The experimental study of characteristics of HXR produced by multi-planar wire arrays, compact cylindrical wire array (CCWA) and nested cylindrical wire array (NCWA) made from Al, Cu, Mo, Ag, W and Au were analyzed. The dependence of the HXR yield and power on geometry of the load, the wire material, and load mass was observed. The presence of aluminum wires in the load with the main material such as stainless steel, Cu, Mo, Ag, W or Au in combined wire array decreases HXR yield. The comparison of emission characteristics of HXR and generation of electron beams in CCWA and NCWA on both the high impedance Zebra generator and low impedance COBRA generator were investigated. Some of the "cold" K- shell spectral lines (0.7-2.3Á) and cold L-shell spectral lines (1-1.54Á) in the HXR region were observed only during the interaction of electron beam with load material and anode surface. These observations suggest that the mechanism of HXR emission should be associated with non-thermal mechanisms such as the interaction of the electron beam with the load material. In order to estimate the characteristics of the high-energetic electron beam in Z-pinch plasmas, a hard x-ray polarimeter (HXP) has been developed and used in experiments on the Zebra generator. The electron beams (energy more than 30keV) have been investigated with measurements of the polarization state of the emitted bremsstrahlung radiation from plasma. We also analyzed characteristics of energetic electron beams produced by implosions of multi-planar wire arrays, compact cylindrical and nested wire arrays as well as X-pinches. Direct indications of electron beams (electron cutoff energy EB from 42-250 keV) were obtained by using the measured current of a Faraday cup placed above the anode or mechanical damage observed in the anode surface. A comparison of total electron beam energy and the spatial and spectral analysis of the parameters of plasmas were investigated for different wire materials. The dependences of the total electron beam energy (E b) on the wire material and the geometry of the wire array load were studied.

  5. Indirect Drive Inertial Confinement Fusion Hohlraum Physics Using A 1-2 MJ Z-pinch X-ray Source

    Microsoft Academic Search

    R. J. Leeper

    2003-01-01

    An indirect drive inertial confinement fusion (ICF) research program using Z-pinch driven hohlraums is being pursued at Sandia National Laboratories (SNL). Indirect drive ICF uses a soft x-ray radiation field located in a radiation cavity or hohlraum to drive a DT capsule implosion. This research is being conducted on SNL's Z facility, which is capable of driving peak currents of

  6. Production of Thermonuclear Neutrons from Deuterium-Filled Capsule Implosions Driven by Z-Pinch Dynamic Hohlraums

    Microsoft Academic Search

    C. L. Ruiz; G. W. Cooper; S. A. Slutz; J. E. Bailey; G. A. Chandler; T. J. Nash; T. A. Mehlhorn; R. J. Leeper; D. Fehl; A. J. Nelson; J. Franklin; L. Ziegler

    2004-01-01

    Evidence for the first production of thermonuclear neutrons by Z-pinch dynamic hohlraum driven deuterium-filled capsules is presented. The average neutron energy and yield isotropy measured is consistent with thermonuclear fusion production. The addition of Xe gas to certain capsules suppressed the fusion neutron yields by an order of magnitude, consistent with a thermonuclear production process. The ion temperature deduced from

  7. Wavelets, Curvelets and Multiresolution Analysis Techniques in Fast Z Pinch Research

    E-print Network

    Afeyan, Bedros; Starck, Jean Luc; Cuneo, Michael

    2012-01-01

    Z pinches produce an X ray rich plasma environment where backlighting imaging of imploding targets can be quite challenging to analyze. What is required is a detailed understanding of the implosion dynamics by studying snapshot images of its in flight deformations away from a spherical shell. We have used wavelets, curvelets and multiresolution analysis techniques to address some of these difficulties and to establish the Shell Thickness Averaged Radius (STAR) of maximum density, r*(N, {\\theta}), where N is the percentage of the shell thickness over which we average. The non-uniformities of r*(N, {\\theta}) are quantified by a Legendre polynomial decomposition in angle, {\\theta}, and the identification of its largest coefficients. Undecimated wavelet decompositions outperform decimated ones in denoising and both are surpassed by the curvelet transform. In each case, hard thresholding based on noise modeling is used.

  8. Self-organization observed in numerical simulations of a hard-core diffuse Z pinch

    SciTech Connect

    Makhin, V.; Siemon, R.E.; Bauer, B.S.; Esaulov, A.; Lindemuth, I.R.; Sotnikov, V.I.; Ryutov, D.D.; Sheehey, P.T. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2005-04-15

    A hard-core Z-pinch plasma (metal conductor on axis) with an unstable pressure profile can rearrange itself through m=0 interchange motions to produce a stable pressure profile. In this paper the self-organization process is demonstrated in numerical simulations of an experimental plasma formation process, using a two-dimensional compressible two-fluid magnetohydrodynamic code. The stabilization process results in m=0 turbulence, which has a level of kinetic energy that is saturated typically at a few percent of the plasma thermal energy. Using idealized initial conditions for simulations with an axial sinusoidal density perturbation, it is possible to observe in detail the development of instability and then turbulence. At first a coherent Rayleigh-Taylor type motion grows exponentially, with localized isentropic heating and cooling associated with the motion. Then the bubble and spike structure breaks up and incoherent m=0 turbulence develops.

  9. Wavelets, curvelets, and multiresolution analysis techniques in fast Z-pinch research

    NASA Astrophysics Data System (ADS)

    Afeyan, Bedros; Won, Kirk; Starck, Jean-Luc; Cuneo, Michael

    2003-11-01

    Z pinches produce an X ray rich plasma environment where backlighting imaging of imploding targets can be quite challenging to analyze. What is required is a detailed understanding of the implosion dynamics by studying snapshot images of its in flight deformations away from a spherical shell. We have used wavelets, curvelets and multiresolution analysis techniques to address some of these difficulties and to establish the Shell Thickness Averaged Radius (STAR) of maximum density, r*(N,?) where N is the percentage of the shell thickness over which we average. The non-uniformities of r*(N,?) are quantified by a Legendre polynomial decomposition in angle, ?, and the identification of its largest coefficients. Undecimated wavelet decompositions outperform decimated ones in denoising and both are surpassed by the curvelet transform. In each case, hard thresholding based on noise modeling is used.

  10. 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

  11. Evaluation of the gas puff z pinch as an x-ray lithograhy and microscopy source

    SciTech Connect

    Bailey, J.; Ettinger, Y.; Fisher, A.; Feder, R.

    1982-01-01

    Soft x rays (100--10 000 eV), due to their short wavelength (0.1--10 nm) can play an important role in high resolution microscopy and lithography. The gas puff Z pinch is an intense source of soft x rays. Calorimeter and x ray diode measurements showed that 10% of the stored electrical energy was converted to radiation in the range of 1--10 nm. Commercial photoresist polymethyl methacrylate (PMMA) and some new resists: CR 39, nitrocellulose, were exposed to the pinch radiation. The developed images on the resists have been studied with a scanning electron microscope. The resolution was found to be source limited, but a simple modification can improve the resolution by more than an order of magnitude.

  12. Evaluation of the gas puff z pinch as an x-ray lithography and microscopy source

    NASA Astrophysics Data System (ADS)

    Bailey, J.; Ettinger, Y.; Fisher, A.; Feder, R.

    1982-01-01

    Soft x rays (100-10 000 eV), due to their short wavelength (0.1-10 nm) can play an important role in high resolution microscopy and lithography. The gas puff Z pinch is an intense source of soft x rays. Calorimeter and x ray diode measurements showed that 10% of the stored electrical energy was converted to radiation in the range of 1-10 nm. Commercial photoresist polymethyl methacrylate (PMMA) and some new resists—CR 39, nitrocellulose, were exposed to the pinch radiation. The developed images on the resists have been studied with a scanning electron microscope. The resolution was found to be source limited, but a simple modification can improve the resolution by more than an order of magnitude.

  13. 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. [Institute of High Current Electronics, Siberian Branch, Russian Academy of Sciences, Tomsk 634055 (Russian Federation); Baksht, R. B. [Tel Aviv University, Electrical Discharge and Plasma Laboratory, Tel Aviv 69101 (Israel)

    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.

  14. A compact capacitive probe for high-voltage diagnostic in Z-pinches.

    PubMed

    Wang, Liangping; Han, Juanjuan; Li, Mo; Zhang, Xinjun; Sun, Tieping; Lei, Tianshi

    2013-03-01

    A capacitive divider was arranged on Qiangguang pulsed power generator during a series of wire-array Z-pinch experiments. This divider was designed to measure the voltage acted on the gap of the cathode and anode boards. The probe has a compact construction and is conveniently assembled on the facility. It is also a cheap voltage probe and easy to build by research groups. The probe can monitor a 1 MV high voltage with a 100 ns rise time. The calibration results showed that the probe had an attenuation ratio of 3.3 × 10(5) and a response time less than 5 ns. The uncertainty was estimated to be 3%. PMID:23556818

  15. Use of Faraday probing to estimate current distribution in wire array z pinches

    SciTech Connect

    Bland, S. N.; Ampleford, D. J.; Bott, S. C.; Guite, A.; Hall, G. N.; Hardy, S. M.; Lebedev, S. V.; Shardlow, P.; Harvey-Thompson, A.; Suzuki, F.; Kwek, K. H. [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Department of Physics, University of Malaysia, Kuala Lumpur 50603 (Malaysia)

    2006-10-15

    In order to understand the formation and dynamics of plasma in wire array z-pinch experiments, measurements of the distribution of current throughout the array are required. We present details of two Faraday probing diagnostics aimed at exploring the magnetic fields and hence distribution of current in an array. An imaging Faraday system utilizes a short laser pulse to make estimates of the current distribution in the precursor column formed on axis before implosion. In a second system, a rod of high Verdet constant glass is placed close to the wires of an array and the polarization of a cw laser passing through the rod is monitored to examine the variance of current with time.

  16. X-ray spectroscopy of Cu impurities on NSTX and comparison with Z-pinch plasmas.

    PubMed

    Safronova, A S; Ouart, N D; Lepson, J K; Beiersdorfer, P; Stratton, B; Bitter, M; Kantsyrev, V L; Cox, P G; Shlyaptseva, V; Williamson, K M

    2010-10-01

    X-ray spectroscopy of mid-Z metal impurities is important in the study of tokamak plasmas and may reveal potential problems if their contribution to the radiated power becomes substantial. The analysis of the data from a high-resolution x-ray and extreme ultraviolet grating spectrometer, XEUS, installed on NSTX, was performed focused on a detailed study of x-ray spectra in the range 7-18 A?. These spectra include not only commonly seen iron spectra but also copper spectra not yet employed as an NSTX plasma impurity diagnostic. In particular, the L-shell Cu spectra were modeled and predictions were made for identifying contributions from various Cu ions in different spectral bands. Also, similar spectra, but from much denser Cu plasmas produced on the UNR Z-pinch facility and collected using the convex-crystal spectrometer, were analyzed and compared with NSTX results. PMID:21034004

  17. Measurement of instability growth in a magnetized Z pinch in the finite-Larmor-radius regime.

    PubMed

    Davies, H M; Dangor, A E; Coppins, M; Haines, M G

    2001-10-01

    The development of the m = 0 instability in a Z pinch was followed and the measured growth rates compared with 2D MHD simulations. Where MHD is valid, the measured growth rates agree well with simulation. Where the ions are magnetized, i.e., where the ion-cyclotron frequency is smaller than the ion-collision frequency and the ratio of the ion Larmor radius to pinch radius is of the order of 0.1, the growth rate was smaller than expected by a factor of 2.5. This is as predicted by finite-Larmor-radius theory. The product of the wave number and the pinch radius was ka approximately 2pi and was the same for all conditions. Perturbations as large as 30% of the pinch radius were observed; no nonlinear saturation was evident. PMID:11580657

  18. Symmetric inertial-confinement-fusion-capsule implosions in a double-z-pinch-driven hohlraum.

    PubMed

    Bennett, G R; Cuneo, M E; Vesey, R A; Porter, J L; Adams, R G; Aragon, R A; Caird, J A; Landen, O L; Rambo, P K; Rovang, D C; Ruggles, L E; Simpson, W W; Smith, I C; Wenger, D F

    2002-12-01

    An inertial-confinement-fusion (ICF) concept using two 60-MA Z pinches to drive a cylindrical hohlraum to 220 eV has been recently proposed. The first capsule implosions relevant to this concept have been performed at the same physical scale with a lower 20-MA current, yielding a 70+/-5 eV capsule drive. The capsule shell shape implies a polar radiation symmetry, the first high-accuracy measurement of this type in a pulsed-power-driven ICF configuration, within a factor of 1.6-4 of that required for scaling to ignition. The convergence ratio of 14-21 is to date the highest in any pulsed-power ICF system. PMID:12484951

  19. Hot dense capsule-implosion cores produced by Z-pinch dynamic Hohlraum radiation.

    PubMed

    Bailey, J E; Chandler, G A; Slutz, S A; Golovkin, I; Lake, P W; MacFarlane, J J; Mancini, R C; Burris-Mog, T J; Cooper, G; Leeper, R J; Mehlhorn, T A; Moore, T C; Nash, T J; Nielsen, D S; Ruiz, C L; Schroen, D G; Varnum, W A

    2004-02-27

    Hot dense capsule implosions driven by Z-pinch x rays have been measured using a approximately 220 eV dynamic Hohlraum to implode 1.7-2.1 mm diameter gas-filled CH capsules. The capsules absorbed up to approximately 20 kJ of x rays. Argon tracer atom spectra were used to measure the T(e) approximately 1 keV electron temperature and the n(e) approximately 1-4 x 10(23) cm(-3) electron density. Spectra from multiple directions provide core symmetry estimates. Computer simulations agree well with the peak emission values of T(e), n(e), and symmetry, indicating reasonable understanding of the Hohlraum and implosion physics. PMID:14995784

  20. Ultradense reproducible Z-pinch suitable for CO2 laser-pellet simulation experiments.

    PubMed

    Steel, D G; Rockett, P D; Bach, D R; Colestock, P L

    1978-04-01

    The design and operating characteristics of a unique reproducible linear, high-density (> 10(19) e(-)/cm(3)), low-temperature (17Z-pinch are presented in this paper. It is shown that the temperature and critical density scale length (70-200 microm) of the pinched plasma are favorable for simulating CO(2) laser-pellet experiments. Focused CO(2) laser intensities of 10(12) W/cm(2) result in v(0)/v(th) approximately equal to 2.8 at the critical layer, where v(0) is the quiver velocity of an electron in the laser electric field and v(th) is the electron thermal velocity. PMID:18699124

  1. Two-dimensional magneto-hydrodynamic modeling of carbon fiber Z-pinch experiments

    SciTech Connect

    Chittenden, J.P.; Aliaga Rossel, R.; Lebedev, S.V.; Mitchell, I.H.; Tatarakis, M.; Bell, A.R.; Haines, M.G. [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)] [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

    1997-12-01

    A two-dimensional magneto-hydrodynamic simulation incorporating cold start conditions is used to explain the early phase of carbon fiber Z-pinch experiments. The rapid development of large scale, nonlinear m=0 perturbations in the plasma corona is reproduced. X-ray bright spot formation in the necks of the instability is followed by bright spot bifurcation and fast axial motion. Bright spot bifurcation is found to be due to axial components of the {bold j{times}B} force and occurs off-axis due to the presence of a residual core of unionized carbon. Artificial diagnostic images are generated from the simulations data to allow direct comparison with experimental x-ray imaging and laser probing diagnostics. The accurate reproduction of the experimental images provides confirmation that the experimentally observed features are a repercussion of the non-linear development of the m=0 instability in an ionizing medium. {copyright} {ital 1997 American Institute of Physics.}

  2. Time-resolved K-shell line spectra measurement of z-pinch plasmas

    NASA Astrophysics Data System (ADS)

    Yang, Qingguo; Zhou, Shaotong; Chen, Guanhua; Huang, Xianbin; Cai, Hongchun; Li, Zeren

    2013-11-01

    A Johann-type crystal spectrometer integrated with x-ray PIN diodes has been developed for measuring the time-resolved K-shell line spectra of the imploding Al wire array. In this spectrometer, the PIN diodes are mounted on the Rowland circle of the cylindrical bent crystal with an appointed position to collect the line emissions from z-pinch plasmas. The spectrometer with four typical channels, which are keyed to the Al ion hydrogen-like (H?, 0.7171 nm and H?, 0.6052 nm) and helium-like (He?, 0.7757 nm and He?, 0.6634 nm) resonance lines is designed and fabricated. Example data from the experiment on the Yang accelerator are shown and the time-dependent electron temperature is determined from the signal ratios of Al ion H? line to He? line using the collisional and radiative model.

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

    SciTech Connect

    Derzon, M.; Nash, T.; Allshouse, G. [and others

    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.

  4. Z-pinch X-ray spectra obtained with a polarization splitting crystal

    NASA Astrophysics Data System (ADS)

    Presura, R.; Wallace, M. S.; Pereira, N. R.

    2014-10-01

    Anisotropy in a plasma may cause polarization of the spectral lines emitted. For example, the X-rays emitted by Z-pinch plasmas may be polarized if electron beams are present. To detect the polarization, we developed an X-ray spectropolarimeter using a single polarization-splitting crystal. Reflections on intersecting internal planes of the crystal select lines with mutually orthogonal linear polarization. The (10-10) internal planes of a quartz crystal can be used to split several lines of the Al K-shell spectrum according to polarization. We applied this technique to several types of Al wire arrays (cylindrical, conical, and X-pinches), expected to produce increasing beam contributions to the electron population. Peculiarities of the instrument set-up and of the spectra analysis will be presented. This work was supported by DOE, NNSA Grant DE-NA0001834 and cooperative Agreement DE-FC52-06NA27616.

  5. 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.

  6. A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source.

    PubMed

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

    2009-01-01

    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. PMID:20198115

  7. A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source

    PubMed Central

    Silterra, J; Holber, W

    2009-01-01

    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. PMID:20198115

  8. 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 h? = 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.

  9. Amplitude reduction of nonuniformities induced by magnetic Rayleigh-Taylor instabilities in Z-pinch dynamic hohlraums

    NASA Astrophysics Data System (ADS)

    Lemke, R. W.; Bailey, J. E.; Chandler, G. A.; Nash, T. J.; Slutz, S. A.; Mehlhorn, T. A.

    2005-01-01

    Z-pinch plasmas are susceptible to the magnetic Rayleigh-Taylor (MRT) instability. The Z-pinch dynamic hohlraum (ZPDH), as implemented on the Z machine at Sandia National Laboratories, is composed of an annular tungsten plasma that implodes onto a coaxial foam convertor. The collision between tungsten Z pinch and convertor launches a strong shock in the foam. Shock heating generates radiation that is trapped by the tungsten Z pinch. The radiation can be used to implode a fuel-filled, inertial confinement fusion capsule. Hence, it is important to understand the influence that the MRT instability has on shock generation. This paper presents results of an investigation to determine the affect that the MRT instability has on characteristics of the radiating shock in a ZPDH. Experiments on Z were conducted in which a 1.5cm tall, nested array (two arrays with initial diameters of 2.0 and 4.0cm), tungsten wire plasma implodes onto a 5mg/cc, CH2 foam convertor to create a ˜135eV dynamic hohlraum. X-ray pinhole cameras viewing along the ZPDH axis recorded time and space resolved images of emission produced by the radiating shock. These measurements showed that the shock remained circular to within ±30-60?m as it propagated towards the axis, and that it was highly uniform along its height. The measured emission intensities are compared with synthetic x-ray images obtained by postprocessing two-dimensional, radiation magnetohydrodynamic simulations in which the amplitude of MRT perturbations is varied. These simulations accurately reproduce the measured shock trajectory and spatial profiles of the dynamic hohlraum interior emission as a function of time, even for large MRT amplitudes. Furthermore, the radiating shock remains relatively uniform in the axial direction regardless of the MRT amplitude because nonuniformities are tamped by the interaction of the tungsten Z-pinch plasma with the foam. These results suggest that inertial confinement fusion implosions driven by a ZPDH should be relatively free from random radiation symmetry variations produced by Z-pinch instabilities.

  10. Magnetic Rayleigh-Taylor Instability Mitigation and Efficient Radiation Production in Gas Puff Z-Pinch Implosions

    NASA Astrophysics Data System (ADS)

    Sze, Henry

    2006-10-01

    For a long time it was believed that tightness and uniformity of Z-pinch plasmas imploded from large radii are inherently low because the adverse effect of the magnetic Rayleigh-Taylor (RT) instability that distorts the imploding plasma column is stronger for a longer acceleration path. None of the wire-array implosions from a diameter exceeding 7 cm were successful; a significant decrease of the argon K-shell radiation yield was observed when a 2.5 cm diameter annular shell load was replaced with a 4 cm diameter one. We report how we solved the problem of imploding z-pinch plasmas from large initial radii, making it possible to efficiently produce x-ray radiation with z pinches driven by longer current pulses than previously thought possible. Our novel load design[1] that mitigates the RT instability and enhances energy coupling to the radiating plasma column consists of a ``pusher,'' outer region plasma that carries the current and couples energy from the driver, a ``stabilizer,'' inner region plasma that stabilizes the implosion and a ``radiator,'' high-density center jet plasma that radiates. It increased the Ar K-shell yield at 3.46 MA in 200-ns implosions from 12-cm initial diameter by a factor of two, to 21 kJ, matching the yields obtained earlier on the same accelerator with 100-ns implosions. Test results of this load on all other major US accelerators will be presented [2]. Using laser shearing images, we illustrate the RT growth, its suppression and stabilization of an imploding plasma in a structured gas puff load that lead to a high compression, high yield z pinch. Similar images obtained for gas puff loads whose design does not ensure stabilization show the evolution of highly unstable z pinches which perform poorly as radiators. This research points the way to improved z-pinch implosions from large initial radii, either in the form of wire arrays or gas puffs. [1] H. Sze et al., Phys. Rev. Lett. 95, 105001 (2005) [2] J. Levine et al., Phys. Plasma (August 2006)

  11. Z-pinches as intense x-ray sources for high energy density physics applications

    NASA Astrophysics Data System (ADS)

    Matzen, M. Keith

    1996-11-01

    Fast z-pinch implosions can convert more than 10% of the stored electrical energy in a pulsed-power accelerator into x rays. These x rays are produced when an imploding cylindrical plasma, driven by the magnetic field pressure associated with very large axial currents, stagnates upon the cylindrical axis of symmetry. On the Saturn pulsed-power accelerator at Sandia National Laboratories, for example, currents of 6 to 8 MA with a risetime of less than 50 ns are driven through cylindrically-symmetric loads (typically gas jets, arrays of wires, thin foils, or low density foams), producing implosions velocities as high as 100 cm/?s and x-ray energies as high as 500 kJ. The keV component of the resulting x-ray spectrum has been used for many years as a source for material response studies. Alternatively, the x-ray output can be thermalized into a near-Planckian x-ray source by containing it within a large cylindrical radiation case (a hohlraum). These large volume ( 6000 mm^3), long-lived ( 20 ns) radiation sources have recently been used for ICF-relevant ablator physics experiments as well as astrophysical opacity and radiation-material interaction experiments. Magneto-Rayleigh-Taylor instabilities and load symmetry are critical, limiting factors in determining the assembled plasma densities and temperatures, and thus in the x-ray pulsewidths that can be produced on these accelerators. In recent experiments on the Saturn accelerator, these implosion nonuniformities have been minimized by using uniform-fill gas puff loads or by using wire arrays with as many a 192 wires. These techniques produced significant improvements in the pinched plasma quality, reproducibility, and x-ray output power. X-ray pulsewidths of less than 5 ns and peak powers of 75?10 TW have been achieved with arrays of 120 tungsten wires. These powers represent greater than a factor of three in power amplification over the electrical power of the accelerator, and are a record for x-ray powers in the laboratory. When the modification to enable z-pinch implosions on PBFA II is completed, x-ray energies in excess of 1.5 MJ at powers in excess of 150 TW should be reached. These intense x-ray sources offer the potential for performing many new basic physics and fusion-relevant experiments. *This work supported by the U.S. Department of Energy under Contract DE-AC04- 94AL85000.

  12. Effects of compressibility on the magneto-Rayleigh-Taylor instability in Z-pinch implosions with sheared axial flows

    SciTech Connect

    Zhang Yang; Ding Ning [Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China); Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China) and CCAST (World Laboratory), P.O. Box 8730, Beijing 100080 (China)

    2006-02-15

    A linear analysis of the ideal magnetohydrodynamic (MHD) stability of the compressible Z-pinch plasma with axial flow is presented. Comparing with results of incompressible models, compressibility can reduce the growth rate of the magneto-Rayleigh-Taylor (MRT)/Kelvin-Helmholtz (KH) instability and allow sheared axial flows to mitigate the MRT instability far more effectively. The effect of magnetic field, which cannot be detected in an incompressible model, is also investigated. The result indicates that the mitigation effect of magnetic field on the MRT instability becomes significant as the perturbation wave-number increases. Therefore, with the cooperation of sheared axial flow, magnetic field, and plasma compressibility, the stability of the Z-pinch plasma is improved remarkably. In addition, the analysis also suggests that in an early stage of the implosion, because the plasma temperature is relatively low, the compressible model is much more suitable than the incompressible one based on the framework of MHD theory.

  13. The True Symmetry of Double Z Pinch Driven Imploding Shells Using Multiresolution Denoising Techniques on X Ray Backlighting Generated Images

    NASA Astrophysics Data System (ADS)

    Won, Kirk; Afeyan, B.; Stark, J. L.; Cuneo, M.; Bennet, G.; Vesey, R.

    2003-10-01

    We have used various advanced image processing and denoising techniques based on multiresolution analysis to obtain useful X ray images of Double Z Pinch driven imploding shells. The shell thickness averaged (highest density) radius (STAR) is defined for a number of asymmetric shots and STAR curves vs angle are Legendre polynomial decomposed in order to characterize the asymmetry in traditional ICF parlance. The powerful hybrid techniques utilizd in this study include wavelets, curvelets and variational minimization iterations to obtain highly reliable denoising based on data extracted noise modeling as well. Pattern detection based on multiresolution analysis hold very good promise in various applications associated with Z pinches and ICF symmetry studies. STAR performance of various implosions can be optimally tuned using these techniques.

  14. 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. [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States); Mosher, D.; Young, F. C. [L-3 Communications/Titan Group, Reston VA 20190 (United States); Levine, J. S.; Failor, B. H.; Sze, H.; Qi, N.; Banister, J. W. [L-3 Communications/Pulse Sciences, San Leandro CA 94577 (United States); Coleman, P. L. [Alameda Applied Sciences Corporation, San Leandro CA 94577 (United States); Coverdale, C. A.; Deeney, C. [Sandia National Laboratories, Albuquerque NM 87545 (United States)

    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.

  15. The effect of the initial gas density and gas shell profile in a small gas-puff Z-pinch

    Microsoft Academic Search

    Chengrong Li; Tsinchi Yang; Chengmu Luo; Min Han

    1990-01-01

    Summary form only given. The authors determined the thickness and mass of the initial gas shell from three different kinds of nozzles and measured the corresponding X-ray yield (2 keVZ-pinch device which consists of a fast valve, a supersonic nozzle of Mach 4, and a capacitor bank charged to 25-30 kV. They also studied

  16. Polar RadiationFlux Symmetry Measurements in Z-Pinch-Driven Hohlraums with Symmetric Double-Pinch Drive

    Microsoft Academic Search

    D. L. Hanson; R. A. Vesey; M. E. Cuneo Porter Jr.; G. A. Chandler; L. E. Ruggles; W. W. Simpson; H. Seamen; P. Primm; J. Torres; J. McGurn; T. L. Gilliland; P. Reynolds; D. E. Hebron; S. C. Dropinski; D. G. Schroen-Carey; J. H. Hammer; O. Landen; J. Koch

    2000-01-01

    We are currently exploring symmetry requirements of the z-pinch-driven hohlraum concept [1] for high-yield inertial confinement fusion. In experiments on the Z accelerator, the burnthrough of a low-density self-backlit foam ball has been used to diagnose the large time-dependent flux asymmetry of several single-sided-drive hohlraum geometries [2]. We are currently applying this technique to study polar radiation flux symmetry in

  17. Demonstration of Radiation Pulse Shaping with Nested-Tungsten-Wire-Array Z Pinches for High-Yield Inertial Confinement Fusion

    Microsoft Academic Search

    M. E. Cuneo; R. A. Vesey; D. B. Sinars; E. M. Waisman; R. W. Lemke; D. E. Bliss; W. A. Stygar; J. L. Porter; M. G. Mazarakis; G. A. Chandler; T. A. Mehlhorn; J. P. Chittenden; S. V. Lebedev; D. G. Schroen

    2005-01-01

    Nested wire-array Z pinches are shown to generate soft x-ray radiation pulse shapes required for three-shock isentropic compression and hot-spot ignition of high-yield inertial confinement fusion capsules. We demonstrate a reproducible and tunable foot pulse (first shock) produced by interaction of the outer and inner arrays. A first-step pulse (second shock) is produced by inner array collision with a central

  18. Space and time resolved electron density and current measurements in a dense plasma focus Z-pinch

    Microsoft Academic Search

    Niansheng Qi; Steven F. Fulghum; Rahul R. Prasad; Mahadevan Krishnan

    1998-01-01

    Plasma density and current profiles in a Z-pinch are important parameters to understand the implosion and radiation physics. This paper describes measurements of electron density and current at radii of ⩾200 ?m from the axis of a dense plasma focus (DPF) pinch plasma that is imploded by a ≈0.3 MA current pulse. These measurements use laser interferometry and polarimetry. The

  19. Mass profile and instability growth measurements for 300-wire z-pinch implosions driven by 14-18, MA

    Microsoft Academic Search

    Michael Edward Cuneo; Edmund P. Yu; Thomas J. Nash; David Emery Bliss; Porter John Larry Jr; Daniel Brian Sinars; C. Deeney; M. Mazarakis; G. Sarkisov; D. Wenger

    2004-01-01

    We present the first comprehensive study of high wire-number, wire-array Z-pinch dynamics at 14-18 MA using x-ray backlighting and optical shadowgraphy diagnostics. The cylindrical arrays retain slowly expanding, dense wire cores at the initial position up to 60% of the total implosion time. Azimuthally correlated instabilities at the array edge appear during this stage which continue to grow in amplitude

  20. X-ray emission from z pinches at 107 A: Current scaling, gap closure, and shot-to-shot fluctuations

    Microsoft Academic Search

    W. A. Stygar; H. C. Ives; D. L. Fehl; M. E. Cuneo; M. G. Mazarakis; J. E. Bailey; G. R. Bennett; D. E. Bliss; G. A. Chandler; R. J. Leeper; M. K. Matzen; D. H. McDaniel; J. S. McGurn; J. L. McKenney; L. P. Mix; D. J. Muron; J. L. Porter; J. J. Ramirez; L. E. Ruggles; J. F. Seamen; W. W. Simpson; C. S. Speas; R. B. Spielman; K. W. Struve; J. A. Torres; R. A. Vesey; T. C. Wagoner; T. L. Gilliland; M. L. Horry; D. O. Jobe; S. E. Lazier; J. A. Mills; T. D. Mulville; J. H. Pyle; T. M. Romero; J. J. Seamen; R. M. Smelser

    2004-01-01

    We have measured the x-ray power and energy radiated by a tungsten-wire-array z pinch as a function of the peak pinch current and the width of the anode-cathode gap at the base of the pinch. The measurements were performed at 13- and 19-MA currents and 1-, 2-, 3-, and 4-mm gaps. The wire material, number of wires, wire-array diameter, wire-array

  1. Two-dimensional gas density and velocity distributions of a 12-cm-diameter, triple-nozzle argon Z-pinch load

    Microsoft Academic Search

    Niansheng Qi; Bruce H. Failor; Jeff Banister; Jerrold S. Levine; Henry M. Sze; David Lojewski

    2005-01-01

    We have developed a 12-cm-diameter Ar gas Z-pinch load, which produces two annular gas shells and a center gas jet. The two-dimensional (2-D) gas density profiles of the load, in r-? and r-z planes, were measured with submillimeter spatial resolutions using the planar-laser-induced fluorescence (PLIF) method, for conditions used in Z-pinch experiments. Due to interactions between the shells, the net

  2. Study of pulsed soft X-ray source employing a gas-puff Z-pinch plasma device for lithography applications

    Microsoft Academic Search

    G. X. Zhang; X. M. Guo; C. M. Luo; S. Lee; X. Feng

    1997-01-01

    Employing a gas-puff Z-pinch plasma device, we have developed a bright and reliable X-ray source. The Z-pinch plasma was produced by a capacity discharge, using a fast valve to inject an annulus of Argon gas. The total capacitance of circuit is 24muF, and the peak discharge current is 360kA with a quarter-period of 2mus when the capacitor bank was charged

  3. The Role of Strong Coupling in Z-Pinch-Driven Approaches to High Yield Inertial Confinement Fusion

    SciTech Connect

    MEHLHORN,THOMAS A.; DESJARLAIS,MICHAEL P.; HAILL,THOMAS A.; LASH,JOEL S.; ROSENTHAL,STEPHEN E.; SLUTZ,STEPHEN A.; STOLTZ,PETER H.; VESEY,ROGER A.; OLIVER,B.

    1999-11-08

    Peak x-ray powers as high as 280 {+-} 40 TW have been generated from the implosion of tungsten wire arrays on the Z Accelerator at Sandia National Laboratories. The high x-ray powers radiated by these z-pinches provide an attractive new driver option for high yield inertial confinement fusion (ICF). The high x-ray powers appear to be a result of using a large number of wires in the array which decreases the perturbation seed to the magnetic Rayleigh-Taylor (MRT) instability and diminishes other 3-D effects. Simulations to confirm this hypothesis require a 3-D MHD code capability, and associated databases, to follow the evolution of the wires from cold solid through melt, vaporization, ionization, and finally to dense imploded plasma. Strong coupling plays a role in this process, the importance of which depends on the wire material and the current time history of the pulsed power driver. Strong coupling regimes are involved in the plasmas in the convolute and transmission line of the powerflow system. Strong coupling can also play a role in the physics of the z-pinch-driven high yield ICF target. Finally, strong coupling can occur in certain z-pinch-driven application experiments.

  4. Recent experimental results on ICF target implosions by Z-pinch radiation sources and their relevance to ICF ignition studies.

    SciTech Connect

    Bailey, James E.; Chandler, Gordon Andrew; Vesey, Roger Alan; Hanson, David Lester; Olson, Craig Lee; Nash, Thomas J.; Matzen, Maurice Keith; Ruiz, Carlos L.; Porter, John Larry, Jr.; Cuneo, Michael Edward; Varnum, William S.; Bennett, Guy R. (K-tech Corporation, Albuquerque, NM); Cooper, Gary Wayne; Schroen, Diana Grace (Schafer Gorp., Livermore, CA); Slutz, Stephen A.; MacFarlane, Joseph John (Prism Computational Sciences, Madison, WI); Leeper, Ramon Joe; Golovkin, I. E. (Prism Computational Sciences, Madison, WI); Mehlhorn, Thomas Alan; Mancini, Roberto Claudio (University of Nevada, Reno, NV)

    2003-07-01

    Inertial confinement fusion capsule implosions absorbing up to 35 kJ of x-rays from a {approx}220 eV dynamic hohlraum on the Z accelerator at Sandia National Laboratories have produced thermonuclear D-D neutron yields of (2.6 {+-} 1.3) x 10{sup 10}. Argon spectra confirm a hot fuel with Te {approx} 1 keV and n{sub e} {approx} (1-2) x 10{sup 23} cm{sup -3}. Higher performance implosions will require radiation symmetry control improvements. Capsule implosions in a {approx}70 eV double-Z-pinch-driven secondary hohlraum have been radiographed by 6.7 keV x-rays produced by the Z-beamlet laser (ZBL), demonstrating a drive symmetry of about 3% and control of P{sub 2} radiation asymmetries to {+-}2%. Hemispherical capsule implosions have also been radiographed in Z in preparation for future experiments in fast ignition physics. Z-pinch-driven inertial fusion energy concepts are being developed. The refurbished Z machine (ZR) will begin providing scaling information on capsule and Z-pinch in 2006. The addition of a short pulse capability to ZBL will enable research into fast ignition physics in the combination of ZR and ZBL-petawatt. ZR could provide a test bed to study NIF-relevant double-shell ignition concepts using dynamic hohlraums and advanced symmetry control techniques in the double-pinch hohlraum backlit by ZBL.

  5. 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.

  6. Diagnostics of deuterium gas-puff z-pinch experiments on the GIT-12 generator

    NASA Astrophysics Data System (ADS)

    Cikhardt, J.; Klir, D.; Rezac, K.; Kubes, P.; Kravarik, J.; Batobolotova, B.; Sila, O.; Turek, K.; Shishlov, A.; Labetsky, A.; Kokshenev, V.; Chedizov, R.; Ratakhin, N.; Varlachev, V.; Garapatsky, A.; Dudkin, G.; Padalko, V.; GIT-12 Team

    2014-10-01

    Z-pinch experiments with a deuterium gas-puff and an outer plasma shell generated by plasma guns were carried out on the GIT-12 generator at the IHCE in Tomsk. Using this novel configuration of the load, the neutron yields from the DD reaction were significantly increased from 2×1011 up to 3×1012 neutrons per shot at the current level of about 3 MA. In addition to recent experiments, the threshold activation detectors were used in order to get the information about the energy spectrum of the generated neutrons. The copper, indium, and lead samples were irradiated by the pulse of the neutrons generated during the experimental shot. The decay radiation of the products from the reactions 63Cu(n,2n)62Cu, 115In(n, ?) 116 mIn and 206Pb (n,3n)204mPb was observed using gamma spectrometer. According to the used neutron ToF scintillation detectors, the energy of neutrons reaches up to 20 MeV. The work was supported by the MSMT of the Czech Republic research Programs No. ME090871, No. LG13029, by the GACR Grant No. P205/12/0454, Grant CRA IAEA No. 17088 and RFBR research Project No. 13-08-00479-a.

  7. Fully kinetic simulations of dense plasma focus Z-pinch devices.

    PubMed

    Schmidt, A; Tang, V; Welch, D

    2012-11-16

    Dense plasma focus Z-pinch devices are sources of copious high energy electrons and ions, x rays, and neutrons. The mechanisms through which these physically simple devices generate such high-energy beams in a relatively short distance are not fully understood. We now have, for the first time, demonstrated a capability to model these plasmas fully kinetically, allowing us to simulate the pinch process at the particle scale. We present here the results of the initial kinetic simulations, which reproduce experimental neutron yields (~10(7)) and high-energy (MeV) beams for the first time. We compare our fluid, hybrid (kinetic ions and fluid electrons), and fully kinetic simulations. Fluid simulations predict no neutrons and do not allow for nonthermal ions, while hybrid simulations underpredict neutron yield by ~100x and exhibit an ion tail that does not exceed 200 keV. Only fully kinetic simulations predict MeV-energy ions and experimental neutron yields. A frequency analysis in a fully kinetic simulation shows plasma fluctuations near the lower hybrid frequency, possibly implicating lower hybrid drift instability as a contributor to anomalous resistivity in the plasma. PMID:23215497

  8. Dynamics of cylindrically converging precursor plasma flow in wire-array Z -pinch experiments.

    PubMed

    Bott, S C; Lebedev, S V; Ampleford, D J; Bland, S N; Chittenden, J P; Ciardi, A; Haines, M G; Jennings, C; Sherlock, M; Hall, G; Rapley, J; Beg, F N; Palmer, J

    2006-10-01

    This paper summarizes the present understanding of the processes leading to precursor column formation in cylindrical wire arrays on the 1 MA MAGPIE generator at Imperial College London. Direct experimental measurements of the diameter variation during the collapse and formation phase of the precursor column are presented, along with soft x-ray emission, and quantitative radiography. In addition, data from twisted cylindrical arrays are presented which give additional information on the behavior of coronal plasma generated in wire array z pinches. Three stages in precursor column formation are identifiable from the data: broad initial density profile, rapid contraction to small diameter, and slow expansion after formation. The correlation of emission to column diameter variation indicates the contraction phase is a nonlinear collapse resulting from the increasing on-axis density and radiative cooling rate. The variation in the minimum diameter is measured for several array materials, and data show good agreement with a pressure balance model. Comparison of column expansion rates to analytical models allows an estimate of column temperature variation, and estimates of the current in the column are also made. Formation data are in good agreement with both fluid and kinetic modeling, but highlight the need to include collisionless flow in the early time behavior. PMID:17155178

  9. 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.

  10. New Exact MHD Solutions Describing the Stagnating Z-pinch plasma

    NASA Astrophysics Data System (ADS)

    Velikovich, A. L.; Giuliani, J. L.; Thornhill, J. W.; Zalesak, S. T.; Maron, Y.; Starobinets, A.; Yu, E. P.

    2011-10-01

    Recent 3D RMHD simulations at Sandia and experiments at Weizmann Institute of Science have demonstrated that axially and azimuthally averaged dynamics of a strongly radiating stagnated Z-pinch column resembles a self-similar, cylindrically symmetric motion. The cold, rapidly imploding plasma transforms into the hot stagnated plasma heated and compressed in the diverging shock wave that propagates from the pinch axis. The simplest analytical solution describing such flow was given by Noh. Here we discuss generalizations of the classical Noh's solution, which take into account the non-uniform density and velocity profiles in the incident plasma, as well as the presence of azimuthal magnetic field in it. These new solutions are found to be surprisingly close to the observations and simulation results. They have also been used for verification tests of MHD codes. Work supported by DOE/NNSA. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  11. 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. [Plasma Physics, Imperial College, London SW7 2BW (United Kingdom)] [Plasma Physics, Imperial College, London SW7 2BW (United Kingdom); Frank, A.; Blackman, E. G., E-mail: mbocchi@imperial.ac.uk [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States)

    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.

  12. a Computational Investigation of the Limits to Pease-Braginskii Collapse of a Z-Pinch

    NASA Astrophysics Data System (ADS)

    Nielsen, Paul Douglas

    1981-10-01

    A Z-pinch is a magnetohydrodynamic phenomenon that consists of a current carrying cylinder of plasma confined by its self-induced azimuthal magnetic field. The interaction of the z-directed current and the azimuthal field produces a JxB force that is directed radially inward. Ignoring two-dimensional effects, the plasma compresses radially until its internal pressure balances the magnetic pressure. This pressure equilibrium was first described by Bennett in 1934 and is called a Bennett equilibrium. In the late 1950's, Pease and Braginskii independently demonstrated that the Bennett equilibrium was not sufficient for a true equilibrium. Radiative cooling and resistive heating could perturb the plasma's internal pressure. Due to these effects, a plasma otherwise at pressure equilibrium could contract or expand. The current at which a plasma is in Bennett equilibrium and radiative cooling equals ohmic heating is called the Pease-Braginskii current. For an optically thin plasma, a current higher than the Pease -Braginskii current would cause a catastrophic collapse --internal energy continually would be lost through radiation faster than it could be developed through joule heating and the plasma's radius would approach zero. This dissertation investigated 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. The one-dimensional simulations contained in this report demonstrate limits to radiation enhanced collapse that depend on the initial plasma density and the rate of current rise. First, there is a low density, fast current rise limit due to strong shock heating and poor electron -ion and electron-radiation coupling. Second, there is a high density, fast current rise limit due to the relative scaling of the pinch time and the LC circuit's quarter cycle time. Third, there is a high density, slow current rise limit due to the plasma's inertia and opacity. Despite these limits, these simulations indicate a significant regime where one-dimensional radiation enhanced collapse does occur, where radiation fluences are prodigious, and where the collapse is terminated only when the plasma becomes optically thick, trapping energy in the interior of the pinch. Apparent discrepancies between these simulations and experiments are explainable by dimensional and geometric arguments and by the effects of enhanced resistivity. Resistivities of only 5-10 times classical values significantly affect pinch dynamics and reduce pinch densities and radiation fluences. In one dimension, however, neither the ion acoustic nor the lower hybrid drift instabilities significantly affect pinch behavior despite the fact that their thresholds are exceeded. Two-dimensional simulations demonstrate the development of axial flow that reduces densities, energy coupling and radiation while increasing instability induced resistivity. The cumulative effect of this axial flow will terminate Pease-Braginskii collapse earlier than the one-dimensional limit based on the plasma becoming optically thick.

  13. Characteristics and scaling of tungsten-wire-array z -pinch implosion dynamics at 20 MA.

    PubMed

    Cuneo, M E; Waisman, E M; Lebedev, S V; Chittenden, J P; Stygar, W A; Chandler, G A; Vesey, R A; Yu, E P; Nash, T J; Bliss, D E; Sarkisov, G S; Wagoner, T C; Bennett, G R; Sinars, D B; Porter, J L; Simpson, W W; Ruggles, L E; Wenger, D F; Garasi, C J; Oliver, B V; Aragon, R A; Fowler, W E; Hettrick, M C; Idzorek, G C; Johnson, D; Keller, K; Lazier, S E; McGurn, J S; Mehlhorn, T A; Moore, T; Nielsen, D S; Pyle, J; Speas, S; Struve, K W; Torres, J A

    2005-04-01

    We present observations for 20-MA wire-array z pinches of an extended wire ablation period of 57%+/-3% of the stagnation time of the array and non-thin-shell implosion trajectories. These experiments were performed with 20-mm-diam wire arrays used for the double- z -pinch inertial confinement fusion experiments [M. E. Cuneo, Phys. Rev. Lett. 88, 215004 (2002)] on the Z accelerator [R. B. Spielman, Phys. Plasmas 5, 2105 (1998)]. This array has the smallest wire-wire gaps typically used at 20 MA (209 microm ). The extended ablation period for this array indicates that two-dimensional (r-z) thin-shell implosion models that implicitly assume wire ablation and wire-to-wire merger into a shell on a rapid time scale compared to wire acceleration are fundamentally incorrect or incomplete for high-wire-number, massive (>2 mg/cm) , single, tungsten wire arrays. In contrast to earlier work where the wire array accelerated from its initial position at approximately 80% of the stagnation time, our results show that very late acceleration is not a universal aspect of wire array implosions. We also varied the ablation period between 46%+/-2% and 71%+/-3% of the stagnation time, for the first time, by scaling the array diameter between 40 mm (at a wire-wire gap of 524 mum ) and 12 mm (at a wire-wire gap of 209 microm ), at a constant stagnation time of 100+/-6 ns . The deviation of the wire-array trajectory from that of a thin shell scales inversely with the ablation rate per unit mass: f(m) proportional[dm(ablate)/dt]/m(array). The convergence ratio of the effective position of the current at peak x-ray power is approximately 3.6+/-0.6:1 , much less than the > or = 10:1 typically inferred from x-ray pinhole camera measurements of the brightest emitting regions on axis, at peak x-ray power. The trailing mass at the array edge early in the implosion appears to produce wings on the pinch mass profile at stagnation that reduces the rate of compression of the pinch. The observation of precursor pinch formation, trailing mass, and trailing current indicates that all the mass and current do not assemble simultaneously on axis. Precursor and trailing implosions appear to impact the efficiency of the conversion of current (driver energy) to x rays. An instability with the character of an m = 0 sausage grows rapidly on axis at stagnation, during the rise time of pinch power. Just after peak power, a mild m = 1 kink instability of the pinch occurs which is correlated with the higher compression ratio of the pinch after peak power and the decrease of the power pulse. Understanding these three-dimensional, discrete-wire implosion characteristics is critical in order to efficiently scale wire arrays to higher currents and powers for fusion applications. PMID:15903793

  14. Initiation, ablation, precursor formation, and instability analysis of thin foil liner Z-pinches

    NASA Astrophysics Data System (ADS)

    Blesener, Isaac Curtis

    This dissertation presents the results of mostly experimental work studying the early-time behavior of thin foil liners as compared to wire-array Z-pinches. It involves three studies, covering initiation, ablation and precursor formation, and instability analysis. Initiation was studied by observing the optical emission of various thickness (0.6-23.5 ?m Cu) liners using a streak camera. It was found that thinner liners initiated sooner, more quickly, and more uniformly than thicker liners. This correlated well with both an increase in instantaneous dJ/dt at the time of first emission as well as the inductive voltage at the time of first emission. The threshold for uniform initiation was dJ/dt>3.5×1016Acm -2s-1. Uniform initiation is important for liners because nonuniformities could lead to enhanced instabilities and poor liner performance (compression, x-ray production, etc.). Ablation and precursor formation of wire-arrays (16x75 ?m Cu) and liners (6 ?m Cu) were studied using r-? density maps and radial mass profiles created by an axial X pinch radiography diagnostic. These images show very strong differences in this stage of the Z-pinch. Wire-arrays develop complex, azimuthally varying ablation structures that lead to dense precursors. Liners, however, show significantly reduced and azimuthally uniform ablation leading to an order of magnitude less dense precursor on axis. This is likely due to the discrete versus continuous nature of wire-arrays versus liners. With wire-arrays, plasma that is created on the outside of the wires can reach the array axis by being swept through the gaps between the stationary wire cores. In contrast, liners have no “gaps” for plasma to flow through. Therefore, any plasma that is created on the outside of the liner is trapped there until the bulk of the liner moves with the implosion. Consequently, only the plasma that is created on the inside of the liner is able to contribute to precursor formation. This is an important result because reduced precursor formation is important for fuel compression and heating in MagLIF. Less precursor can also lead to enhanced x-ray production because there is less mass on axis to cushion the conversion of kinetic energy into x-rays during the implosion and stagnation phases. Finally, in the instability studies, it was observed in laser shadow graph images that liners develop a much larger amplitude instability on their outside surface as compared to wire-arrays. This is an important discovery and could be detrimental to liner performance (compression, x-ray production, etc.) because it could lead to enhanced magnetic Rayleigh-Taylor (MRT) instability during the implosion phase. The reason for the larger instability in liners is again probably due to the fact that plasma builds up on the outside of the liners with no where to go. A possible source of the enhanced instability was found using 2D (xy) PERSEUS simulations comparing the results of MHD and Hall MHD simulations. The instability only developed in the Hall MHD case. The 2D nature of the simulation, along with all simulation parameters being equal between the two cases, rules out the possibility of MRT or m=0 for the cause of the instability (in the simulation). It was found that the Hall term was responsible for causing a shear-flow instability that developed later in time to resemble the experimental results.

  15. Shock waves in a Z-pinch and the formation of high energy density plasma

    SciTech Connect

    Rahman, H. U. [Magneto-Inertial Fusion Technologies Inc. (MIFTI), Irvine, California 92612 (United States) and Department of Physics, University of California Irvine, Irvine, California 92697 (United States); Wessel, F. J. [Department of Physics, University of California Irvine, Irvine California 92697 (United States); Ney, P. [Mount San Jacinto College, Menifee, California 92584 (United States); Presura, R. [University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0208 (United States); Ellahi, Rahmat [Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan) and Department of Mechanical Engineering, University of California Riverside, Riverside, California 92521 (United States); Shukla, P. K. [Department of Mechanical and Aerospace Engineering and Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)

    2012-12-15

    A Z-pinch liner, imploding onto a target plasma, evolves in a step-wise manner, producing a stable, magneto-inertial, high-energy-density plasma compression. The typical configuration is a cylindrical, high-atomic-number liner imploding onto a low-atomic-number target. The parameters for a terawatt-class machine (e.g., Zebra at the University of Nevada, Reno, Nevada Terawatt Facility) have been simulated. The 2-1/2 D MHD code, MACH2, was used to study this configuration. The requirements are for an initial radius of a few mm for stable implosion; the material densities properly distributed, so that the target is effectively heated initially by shock heating and finally by adiabatic compression; and the liner's thickness adjusted to promote radial current transport and subsequent current amplification in the target. Since the shock velocity is smaller in the liner, than in the target, a stable-shock forms at the interface, allowing the central load to accelerate magnetically and inertially, producing a magneto-inertial implosion and high-energy density plasma. Comparing the implosion dynamics of a low-Z target with those of a high-Z target demonstrates the role of shock waves in terms of compression and heating. In the case of a high-Z target, the shock wave does not play a significant heating role. The shock waves carry current and transport the magnetic field, producing a high density on-axis, at relatively low temperature. Whereas, in the case of a low-Z target, the fast moving shock wave preheats the target during the initial implosion phase, and the later adiabatic compression further heats the target to very high energy density. As a result, the compression ratio required for heating the low-Z plasma to very high energy densities is greatly reduced.

  16. 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.

  17. A study of the stability of the Z pinch under fusion conditions using the Hall fluid model

    NASA Astrophysics Data System (ADS)

    Coppins, M.; Bond, D. J.; Haines, M. G.

    1984-12-01

    The Hall fluid model (a quasineutral two-fluid model with Te=0) is used to investigate the effect of the Hall term on the m=0 instability in a pure Z pinch. The problem is treated numerically by a linearized initial value code. Two different equilibria are investigated. The growth rate of the fastest growing magnetohydrodynamic mode is increased for one equilibrium and reduced for the other by the inclusion of the Hall term, and in the second case new modes with high growth rates are found. The possibility of Hall term destabilization of MHD stable equilibria is suggested.

  18. Pressure and energy balance of stagnating plasmas in z-pinch experiments: implications to current flow at stagnation.

    PubMed

    Maron, Y; Starobinets, A; Fisher, V I; Kroupp, E; Osin, D; Fisher, A; Deeney, C; Coverdale, C A; Lepell, P D; Yu, E P; Jennings, C; Cuneo, M E; Herrmann, M C; Porter, J L; Mehlhorn, T A; Apruzese, J P

    2013-07-19

    Detailed spectroscopic diagnostics of the stagnating plasma in two disparate z pinches allow, for the first time, the examination of the plasma properties within a 1D shock wave picture, demonstrating a good agreement with this picture. The conclusion is that for a wide range of imploding-plasma masses and current amplitudes, in experiments optimizing non-Planckian hard radiation yields, contrary to previous descriptions the stagnating plasma pressure is balanced by the implosion pressure, and the radiation energy is provided by the imploding-plasma kinetic energy, rather than by the magnetic-field pressure and magnetic-field-energy dissipation, respectively. PMID:23909333

  19. A simple technique to estimate the fully time-resolved x-ray diameter of a z pinch.

    PubMed

    Coleman, Philip L

    2007-11-01

    Occultations are routinely used to derive information about astronomical objects. Here an occultation scheme is used to derive a fully time-resolved estimate of the x-ray emitting diameter of a z pinch. By using different filtrations on the sensors, one could for example, distinguish the size of the K-line emitting region compared to the higher energy K-continuum emitting volume. Or with suitable apertures and detector arrays, the pinch diameter could be axially and temporally resolved. PMID:18052469

  20. Double Z-pinch hohlraum drive with excellent temperature balance for symmetric inertial confinement fusion capsule implosions.

    PubMed

    Cuneo, M E; Vesey, R A; Porter, J L; Bennett, G R; Hanson, D L; Ruggles, L E; Simpson, W W; Idzorek, G C; Stygar, W A; Hammer, J H; Seamen, J J; Torres, J A; McGurn, J S; Green, R M

    2002-05-27

    A double Z pinch driving a cylindrical secondary hohlraum from each end has been developed which can indirectly drive intertial confinement fusion capsule implosions with time-averaged radiation fields uniform to 2%-4%. 2D time-dependent view factor and 2D radiation hydrodynamic simulations using the measured primary hohlraum temperatures show that capsule convergence ratios of at least 10 with average distortions from sphericity of /r200 MJ. PMID:12059481

  1. Enhanced keV peak power and yield using twisted pair ``cables'' in a z-pinch

    NASA Astrophysics Data System (ADS)

    Hoyt, C. L.; Knapp, P. F.; Pikuz, S. A.; Shelkovenko, T. A.; Cahill, A. D.; Gourdain, P.-A.; Greenly, J. B.; Kusse, B. R.; Hammer, D. A.

    2012-06-01

    Individual wires in a z-pinch were replaced with twisted pair "cables" of similar linear mass on the COBRA pulsed power generator, resulting in peak power and yield increases in radiation above 1 keV. A cable is defined here as two or more fine wires twisted together to form a continuous strand with a wavelength (?t) dependent on the twists per unit length. The magnitude of ?t appears to play a strong role in these increases, with the largest gains found for a ?t of ?0.75 mm.

  2. 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.

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

    DOE PAGESBeta

    Vogman, G. V.; Shumlak, U.

    2011-01-01

    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. These measurements are used to gain a better understanding of Z-pinch equilibria.« less

  4. Aximuthal Structure Observed and Modeled in Annular Wire-Array Z-Pinches Having a Solid Current-Return Anode

    NASA Astrophysics Data System (ADS)

    Sanford, T. W. L.; Mock, R. C.; Struve, K. W.; Roderick, N. F.

    2001-10-01

    Periodic structure associated with the periodic slots in the anode current-return (typically used for pinch viewing) is both expected and observed in x-ray images of a z-pinch. This paper discusses the azimuthal structure observed and modeled, for the first time, in high-wire number z-pinches where the current return is essentially a solid annular shell with no azimuthal structure. The geometry is that of Fig. 2 in Ref. 1, where a nested array of tungsten wires is imploded with either no target or a low-density foam target on axis. In either configuration, a quasi-periodic azimuthal structure, with mode number 6±2, is observed in x-ray images of the pinch, when viewed from above through a small radiation-exit-hole. Similar mode structures are generated near stagnation in numerical simulations, which assume in the outer array either (1) a fixed initial azimuthal density variation with mode number 6 or (2) simply an initial random density variation. In the full paper, the measured and modeled simulations with the solid current return anode are contrasted with those measured and modeled with the anode slots. [1] T. W. L. Sanford, R. E. Olson, R. C. Mock, et al, Phys.Plasmas 7, 4669 (2000). *Sandia is a multiprogram laboratory operated by the Sandia Corporation, a Lockheed Martin Company, for the U.S. Department of Energy under Contract No. DE-AC04-94AL85000.

  5. Formation of hot spots in the plasma of a Z-pinch produced from low-density deuterated polyethylene

    SciTech Connect

    Akunets, A. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Anan'ev, S. S.; Bakshaev, Yu. L.; Blinov, P. I.; Bryzgunov, V. A.; Vikhrev, V. V.; Volobuev, I. V.; Dan'ko, S. A.; Zelenin, A. A.; Kazakov, E. D.; Korolev, V. D.; Meshcherov, B. R.; Nedoseev, S. L. [Russian Research Centre Kurchatov Institute (Russian Federation); Pimenov, V. G. [Russian Academy of Sciences, Zelinsky Institute of Organic Chemistry (Russian Federation); Smirnova, E. A.; Ustroev, G. I.; Chernenko, A. S.; Shchagin, V. A. [Russian Research Centre Kurchatov Institute (Russian Federation)

    2010-08-15

    Results are presented from experimental studies of the plasma formation dynamics in a Z-pinch produced from a cylindrical microporous agar-agar load. The experiments were performed on the S-300 facility at a current of 2 MA and current rise time of 100 ns. To enhance the energy concentration, a deuterated polyethylene neck with a mass density of 50-75 {mu}g/cm{sup 3} and diameter of 1-2 mm was made in the central part of the load. The spatiotemporal characteristics of the Z-pinch were studied using an optical streak camera and fast frame photography in the optical and soft X-ray spectral ranges. X-ray emission was detected using semiconductor and vacuum diodes, and neutron emission was studied by means of the time-of-flight method. It is found that, in the course of continuous plasma production, hot spots with a diameter of 100 {mu}m form in the pinch plasma. The hot spots emit short soft X-ray pulses with a duration of 2-4 ns, as well as neutron pulses with an average neutron energy of about 2.45 MeV. The maximum neutron yield was found to be 4.5 x 10{sup 9} neutrons per shot. The scenario of hot spot formation is adequately described by two-dimensional MHD simulations.

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

    PubMed

    Vogman, G V; Shumlak, U

    2011-10-01

    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. These measurements are used to gain a better understanding of Z-pinch equilibria. PMID:22047291

  7. Abel inversion of a holographic interferogram for determination of the density profile of a sheared-flow Z pinch

    SciTech Connect

    Jackson, S. L.; Shumlak, U. [Aerospace and Energetics Research Program, University of Washington, Seattle, Washington 98195-2250 (United States)

    2006-08-15

    A holographic interferometer is used to determine the radial electron number density profile of a sheared-flow Z pinch. Chord-integrated density information is recorded during a plasma pulse using the expanded beam of a pulsed ruby laser and holographic techniques. An Interactive Data Language (IDL) computer routine that requires only minimal user interaction is used to measure the resulting fringe shift in the reconstructed interferogram. This chord-integrated density information is inverted using an Abel inversion to determine the radial electron density profile. The density profiles obtained show a radially symmetric plasma column with an electron density of 10{sup 16}-10{sup 17} cm{sup -3} above the background plasma density. Holographic measurements are made at different times on separate plasma pulses to track the evolution of the density profile over time. These measurements are corroborated by time-dependent measurements made using a He-Ne interferometer.

  8. Efficient radiation production in long implosions of structured gas-puff Z pinch loads from large initial radius.

    PubMed

    Sze, H; Banister, J; Failor, B H; Levine, J S; Qi, N; Velikovich, A L; Davis, J; Lojewski, D; Sincerny, P

    2005-09-01

    We have proposed and demonstrated successfully a new approach for generating high-yield K-shell radiation with large-diameter gas-puff Z pinches. The novel load design consists of an outer region plasma that carries the current and couples energy from the driver, an inner region plasma that stabilizes the implosion, and a high-density center jet plasma that radiates. It increased the Ar K-shell yield at 3.46 MA in 200 ns implosions from 12 cm initial diameter by a factor of 2, to 21 kJ, matching the yields obtained earlier on the same accelerator with 100 ns implosions. A new "pusher-stabilizer-radiator" physical model is advanced to explain this result. PMID:16196936

  9. 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. 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.

  10. Fusion neutron detector for time-of-flight measurements in z-pinch and plasma focus experiments.

    PubMed

    Klir, D; Kravarik, J; Kubes, P; Rezac, K; Litseva, E; Tomaszewski, K; Karpinski, L; Paduch, M; Scholz, M

    2011-03-01

    We have developed and tested sensitive neutron detectors for neutron time-of-flight measurements in z-pinch and plasma focus experiments with neutron emission times in tens of nanoseconds and with neutron yields between 10(6) and 10(12) per one shot. The neutron detectors are composed of a BC-408 fast plastic scintillator and Hamamatsu H1949-51 photomultiplier tube (PMT). During the calibration procedure, a PMT delay was determined for various operating voltages. The temporal resolution of the neutron detector was measured for the most commonly used PMT voltage of 1.4 kV. At the PF-1000 plasma focus, a novel method of the acquisition of a pulse height distribution has been used. This pulse height analysis enabled to determine the single neutron sensitivity for various neutron energies and to calibrate the neutron detector for absolute neutron yields at about 2.45 MeV. PMID:21456735

  11. A novel extreme ultraviolet four channels normal incidence imaging system for plasma diagnostics of Z-pinch facility.

    PubMed

    Wang, Xin; Mu, Baozhong; Zhu, Jingtao; Wang, Ling; Yi, Shengzhen; Li, Wenbin; Wang, Zhanshan; Qin, Yi; Xu, Zeping; Xu, Rongkun; Li, Zhenghong

    2013-07-01

    A novel EUV four channels normal incidence imaging system for plasma diagnostics of Z-pinch facility was presented in this paper, which consists of four concave mirrors and one convex mirror used for focusing an object onto four different positions with about 30 ?m resolution on the same image plane. In addition, this imaging system can work at the energies of 50 eV, 95 eV, 150 eV, and broadband of 50-100 eV by using different multilayer films deposited on the concave and convex mirrors. This instrument, combined with framing camera, can achieve the power of two-dimensional spatial and temporal resolution, as well as the ability to imaging the plasma at the specific temperature. In the paper, the four channels microscope centering at multi-energies was developed. PMID:23902074

  12. Hemispherical Capsule Implosion Measurements in a Z-Pinch-Driven Fast Ignitor Fuel Compression Geometry

    Microsoft Academic Search

    D. L. Hanson; R. A. Vesey; S. A. Slutz; M. E. Cuneo; J. L. Porter; R. G. Adams; G. A. Chandler; S. C. Dropinski; D. W. Johnson; K. L. Keller; J. S. McGurn; P. K. Rambo; L. E. Ruggles; W. W. Simpson; C. S. Speas; J. A. Torres; I. C. Smith; G. R. Bennett; R. Green; H. Seamen; R. M. Smelser; T. L. Gilliland; T. E. Cowan; D. G. Schroen; D. L. Tanner

    2002-01-01

    In the fast ignitor approach to inertial fusion [Tabak et al., Phys. Plasmas 1, 1626 (1994)], ignition is produced by heating highly-compressed fuel with a fast, ultra-high power laser pulse. By separating the fuel compression and fast heating processes, symmetry and energy requirements for ignition are significantly relaxed. Laser propagation issues can be avoided by maintaining a plasma-free path for

  13. Modifying wire-array Z-pinch ablation structure using coiled arrays.

    PubMed

    Hall, G N; Chittenden, J P; Bland, S N; Lebedev, S V; Bott, S C; Jennings, C; Palmer, J B A; Suzuki-Vidal, F

    2008-02-15

    A new wire-array configuration has been used to control the modulation of ablated plasma flow for the first time. Cylindrical aluminum coiled arrays, in which each straight wire is replaced with a single helix, were driven by a 1 MA, 240 ns current pulse. Ablated plasma is directed away from the coiled wire cores in a manner that can be understood in terms of Lorentz forces that arise from a complex current path modeled by 3D magnetohydrodynamic simulations. Outside the diameter of the helix, the flow of ablated plasma is axially modulated at the wavelength of the coil. PMID:18352483

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

    SciTech Connect

    Thornhill, J. W.; Chong, Y. K.; Apruzese, J. P.; Davis, J.; Clark, R. W.; Giuliani, J. L. Jr.; 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. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States); Berkeley Scholars, Beltsville, Maryland 20705 (United States); NumerEx, Albuquerque, New Mexico 87106 (United States); L-3 Communications/Pulse Sciences, San Leandro, California 94577 (United States); Alameda Applied Sciences, San Leandro, California 94577 (United States); Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); National Nuclear Security Administration, Washington, D.C. 20585 (United States)] (and others)

    2007-06-15

    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 12 cm diameter nozzle with and without a central gas jet on axis. Typical peak drive currents and implosion times in these experiments were {approx}6 MA and {approx}230 ns. 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-shell yield behavior for Sandia National Laboratories' ZR machine ({approx}25 MA peak drive currents, {approx}100 ns implosion times) [D. McDaniel et al., Proceedings of the 5th International Conference on Dense Z-Pinches, Albuquerque, NM, 2002, edited by J. Davis, C. Deeney, and N. R. Pereira (American Institute of Physics, New York, 2002), Vol. 651, p. 23] for experiments that utilize the 12 cm diameter central-jet nozzle configuration, it predicts over 1 MJ of K-shell emission is attainable.

  15. 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. 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.

  16. Characteristics for the Occurrence of a High-Current Z-Pinch Aurora as Recorded in Antiquity Part II: Directionality and Source

    Microsoft Academic Search

    Anthony L. Peratt; John McGovern; Alfred H. Qoyawayma; Marinus Anthony Van der Sluijs; Mathias G. Peratt

    2007-01-01

    The discovery that objects from the Neolithic or Early Bronze Age carry patterns associated with high-current Z-pinches provides a possible insight into the origin and meaning of these ancient symbols produced by humans. Part I deals with the comparison of graphical and radiation data from high-current -pinches to petroglyphs, geoglyphs, and megaliths. Part I focused primarily, but not exclusively, on

  17. TOPICAL REVIEW: Progress in symmetric ICF capsule implosions and wire-array z-pinch source physics for double-pinch-driven hohlraums

    Microsoft Academic Search

    M. E. Cuneo; R. A. Vesey; G. R. Bennett; D. B. Sinars; W. A. Stygar; E. M. Waisman; J. L. Porter; P. K. Rambo; I. C. Smith; S. V. Lebedev; J. P. Chittenden; D. E. Bliss; T. J. Nash; G. A. Chandler; B. B. Afeyan; E. P. Yu; R. B. Campbell; R. G. Adams; D. L. Hanson; T. A. Mehlhorn; M. K. Matzen

    2006-01-01

    Over the last several years, rapid progress has been made evaluating the double-z-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas 6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough to drive a high yield ICF capsule. The secondary hohlraum is

  18. Equilibrium Evolution in the ZaP Flow Z-Pinch U. Shumlak, C.S. Adams, R.P. Golingo, D.J. Den Hartog, S.L. Jackson, S. D. Knecht, K. A.

    E-print Network

    Wisconsin at Madison, University of

    1 IC/P7-11 Equilibrium Evolution in the ZaP Flow Z-Pinch U. Shumlak, C.S. Adams, R.P. Golingo, D Research Program, University of Washington, Seattle, WA, USA e-mail contact of main author: shumlak@aa.washington.edu Abstract. The ZaP Flow Z-pinch experiment at the University of Washington investigates the innovative

  19. 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. PMID:19044561

  20. 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. [Sandia National Laboratories, Albuquerque, New Mexico 8718 (United States); Serrano, J. D.; Nielsen-Weber, L. B.; Meyer, C. J. [Ktech Corporation, Albuquerque, New Mexico 87123 (United States); Apruzese, J. P.; Clark, R. W. [Naval Research Laboratory, Washington, DC 20375 (United States); Coleman, P. L. [Alameda Applied Sciences Corp., San Leandro, California 94577 (United States)

    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.

  1. Z-Beamlet Point Projection X-Ray Imaging of ICF Implosions in Z Accelerator Z-Pinch-Driven Hohlraums

    NASA Astrophysics Data System (ADS)

    Bennett, G. R.; Adams, R. G.; Cuneo, M. E.; Dropinski, S. C.; Green, R. M.; Hurst, M. J.; Porter, J. L.; Rambo, P.; Rovang, D. C.; Ruggles, L. E.; Seamen, H.; Simpson, W. W.; Tanner, D. L.; Vesey, R. A.; Wenger, D. F.; Smith, I. C.

    2001-10-01

    The Z-Beamlet laser backlighter system, a recent addition to Sandia's 20-MA Z accelerator, will be used to point project x-ray image a variety of Z-driven targets (Rev. Sci. Instrum. 72, 657 (2001). and references therein). This laser is a 2-TW, 2-kJ system and when fully commissioned it will have a <50-?m-diam spot size and a four-post picket fence pulse for high-spatial-resolution four-frame imaging. Although the point projection imaging mode forces the image plane detector to view through a large aperture, making it therefore sensitive to both the Bremsstrahlung background and debris characteristic of Z, recent data shows success in overcoming both these problems. In particular, as part of the z-pinch-driven hohlraum high-yield ICF assessment study (Phys. Plasmas. 8, 2257 (2001). and references therein) initial Z-Beamlet-backlit images of imploding ICF capsules have been captured, and will be presented. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin Company, for the USDOE under Contract DE-AC04-94AL85000.

  2. Fast z-pinches as dense plasma, intense x-ray sources for plasma physics and fusion applications

    NASA Astrophysics Data System (ADS)

    Matzen, M. K.; Deeney, C.; Leeper, R. J.; Porter, J. L.; Spielman, R. B.; Chandler, G. A.; Derzon, M. S.; Douglas, M. R.; Fehl, D. L.; Hebron, D. E.; Nash, T. J.; Olson, R. E.; Ruggles, L. E.; Sanford, T. W. L.; Seamen, J. F.; Struve, K. W.; Stygar, W. A.; Peterson, D. L.

    1999-03-01

    As a result of advances in fast pulsed-power technology and cylindrical load fabrication, the Z pulsed-power accelerator at Sandia National Laboratories drives currents approaching 20 MA with a rise time of approximately 100 ns through cylindrically-symmetric loads (typically a cylindrical array consisting of a few hundred wires) to produce plasma densities in excess of 0741-3335/41/3A/011/img21, x-ray output energies approaching 2 MJ, radiation pulses as short as 4 ns and peak x-ray powers as high as 0741-3335/41/3A/011/img22. More than 15% of the stored electrical energy in the Z pulsed-power accelerator is converted into x-rays. The plasma pressures at peak compression are several TPa with electron temperatures that can exceed 3 keV at containment magnetic fields exceeding 1000 T. Depending on the atomic number and composition of the imploding plasma, these z-pinches can be tailored to produce intense sources of thermal x-rays, keV x-rays or neutrons. Although applications of these x-ray sources have included research in radiation material interaction, equations of state, opacity, astrophysics and x-ray lasers, the principal focus of the present research is to use them for indirect-drive inertial confinement fusion (ICF).

  3. Ion viscous heating in a magnetohydrodynamically unstable Z pinch at over 2 x 10(9) Kelvin.

    PubMed

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

    2006-02-24

    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 x 10(9) degrees), as predicted by theory. These are believed to be record temperatures for a magnetically confined plasma. PMID:16606100

  4. 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, ?t ~10 ?s) 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.

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

    SciTech Connect

    BOWERS,RICHARD; CHANDLER,GORDON A.; HEBRON,DAVID E.; LEEPER,RAMON J.; MATUSLKA,WALTER; MOCK,RAYMOND CECIL; NASH,THOMAS J.; OLSON,CRAIG L.; PETERSON,BOB; PETERSON,DARRELL; RUGGLES,LAURENCE E.; SANFORD,THOMAS W. L.; SIMPSON,WALTER W.; STRUVE,KENNETH W.; VESEY,ROGER A.

    1999-11-01

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch magnet 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 {approx}85 eV for a duration of {approx}10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm{sup 3} CH generates first-step-pulse conditions of {approx}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 {approx}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{approx}(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.

  6. Observation of emission process in hydrogen-like nitrogen Z-pinch discharge with time integrated soft X-ray spectrum pinhole image

    SciTech Connect

    Sakai, Y.; Kumai, H.; Nakanishi, Y.; Ishizuka, Y.; Takahashi, S.; Komatsu, T.; Xiao, Y.; Bin, H.; Quishi, Z.; Hayashi, Y.; Song, I.; Kawamura, T.; Watanabe, M.; Hotta, E. [Department of Energy Sciences, Tokyo Institute of Technology, Nagatsuta, Midoriku, Yokohama, Kanagawa 226-8502 (Japan); Rosenzweig, J. [Department of Physics and Astronomy, University of California Los Angeles, 405 Hilgard Ave., Los Angeles, California 90095 (United States)

    2013-02-15

    The emission spectra of hydrogen-like nitrogen Balmer at the wavelength of 13.4 nm in capillary Z-pinch discharge plasma are experimentally examined. Ionization to fully strip nitrogen at the pinch maximum, and subsequent rapid expansion cooling are required to establish the population inversion between the principal quantum number of n = 2 and n = 3. The ionization and recombination processes with estimated plasma parameters are evaluated by utilizing a time integrated spectrum pinhole image containing radial spatial information. A cylindrical capillary plasma is pinched by a triangular pulsed current with peak amplitude of 50 kA and pulse width of 50 ns.

  7. Mass-profile and instability-growth measurements for 300-wire Z-pinch implosions driven by 14-18 MA.

    PubMed

    Sinars, D B; Cuneo, M E; Yu, E P; Bliss, D E; Nash, T J; Porter, J L; Deeney, C; Mazarakis, M G; Sarkisov, G S; Wenger, D F

    2004-10-01

    We present the first comprehensive study of high wire-number, wire-array Z-pinch dynamics at 14-18 MA using x-ray backlighting and optical shadowgraphy diagnostics. The cylindrical arrays retain slowly expanding, dense wire cores at the initial position up to 60% of the total implosion time. Azimuthally correlated instabilities at the array edge appear during this stage which continue to grow in amplitude and wavelength after the start of bulk motion, resulting in measurable trailing mass that does not arrive on axis before peak x-ray emission. PMID:15524803

  8. Observations of modified three-dimensional instability structure for imploding z-pinch liners that are premagnetized with an axial field.

    PubMed

    Awe, T J; McBride, R D; Jennings, C A; Lamppa, D C; Martin, M R; Rovang, D C; Slutz, S A; Cuneo, M E; Owen, A C; Sinars, D B; Tomlinson, K; Gomez, M R; Hansen, S B; Herrmann, M C; McKenney, J L; Nakhleh, C; Robertson, G K; Rochau, G A; Savage, M E; Schroen, D G; Stygar, W A

    2013-12-01

    Novel experimental data are reported that reveal helical instability formation on imploding z-pinch liners that are premagnetized with an axial field. Such instabilities differ dramatically from the mostly azimuthally symmetric instabilities that form on unmagnetized liners. The helical structure persists at nearly constant pitch as the liner implodes. This is surprising since, at the liner surface, the azimuthal drive field presumably dwarfs the axial field for all but the earliest stages of the experiment. These fundamentally 3D results provide a unique and challenging test for 3D-magnetohydrodynamics simulations. PMID:24476283

  9. Planar wire-array Z-pinch implosion dynamics and X-ray scaling at multiple-MA drive currents for a compact multisource hohlraum configuration.

    PubMed

    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. PMID:20366539

  10. Pulsed current wave shaping with a transmission line by utilizing superposition of a forward and a backward voltage wave for fast capillary Z-pinch discharge.

    PubMed

    Sakai, Y; Takahashi, S; Watanabe, M; Kim, G-H; Hotta, E

    2010-04-01

    By using a water transmission line, current wave shaping was demonstrated for a fast capillary Z-pinch discharge recombination soft x-ray laser study. The pulsed power system consists of a water capacitor, a gap switch, a transmission line, and a capillary plasma load. A voltage wave initiated at the water capacitor propagates toward the capillary load through the transmission line. Control of the pulse delay that occurred in the transmission line provides the superposition of the forward and the backward voltage waves effectively in order to perform current wave shaping with higher current amplitude and rapid current decay. PMID:20441338

  11. 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. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Serrano, J. D. [Ktech Corp., Albuquerque, New Mexico 87123 (United States); Vigil, M. P. [LMATA Government Services LLC, Albuquerque, New Mexico 87109 (United States); Esaulov, A. A.; Kantsyrev, V. L.; Safronova, A. S.; Williamson, K. M. [University of Nevada, Reno, Nevada 89557 (United States); Chuvatin, A. S. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau (France); Rudakov, L. I. [Icarus Research, Bethesda, Maryland 20824-0780 (United States)

    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.

  12. 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. [Department of Energy Sciences, Tokyo Institute of Technology, 4259 J2-35 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)] [Department of Energy Sciences, Tokyo Institute of Technology, 4259 J2-35 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

    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.

  13. 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. PMID:22938283

  14. COBRA-STAR, a five frame point-projection x-ray imaging system for 1 MA scale wire-array Z pinches.

    PubMed

    Douglass, J D; Hammer, D A

    2008-03-01

    A new imaging system for 1 MA scale wire-array Z-pinch experiments that produces up to five high-resolution x-ray images per experimental pulse has been developed. Calibrated areal density measurements of the Z-pinch plasma can be obtained from each pulse. The system substitutes five molybdenum (Mo) X pinches for the normal copper return-current conductors to provide point sources of x-rays for point-projection radiography. Each backlighting X pinch consists of four Mo wires, the x-ray burst timing of which was controlled by varying the wire diameter (mass) from 10.2 to 30 microm in the five X pinches. Typical images have a 16x8 mm2 field of view at the wire array and a magnification of about 6.5:1 on the x-ray-sensitive film. Titanium (Ti) filters in front of the films transmit continuum radiation in the spectral range of 3-5 keV. Inclusion on the Ti of a step wedge having known thickness increments of the same material as the wires enables the calibrated areal density measurements to be made of the exploding wire plasmas. Here, we used tungsten (W) step wedges with step thicknesses ranging from 0.015 to 1.1 microm to obtain accurate (+/-10%) areal density measurements of W plasmas from the spatial profile of film exposure. When imaging arrays that produce intense radiation pulses, a plastic monofilament "quencher" is placed on axis to avoid film saturation. Images have subnanosecond temporal resolution and about 7 microm spatial resolution. PMID:18377006

  15. Two-dimensional magnetohydrodynamic liner-on-plasma simulations for the compression phase of a magnetized target fusion system based on inverse Z pinch

    SciTech Connect

    Subhash, P. V.; Madhavan, S.; Chaturvedi, S. [Institute for Plasma Research, Bhat, Gandhinagar-382 428, Gujarat (India)

    2006-07-15

    This article reports, for the first time, two-dimensional magnetohydrodynamic liner-on-plasma simulations for the compression phase of a magnetized target fusion (MTF) system with an inverse Z-pinch target. These simulations evolve the complete liner-plasma system along with the driving pulsed-power source. First, it has been demonstrated that closely coupled liner-on-plasma simulations produce results that are significantly different from loosely coupled simulations that have been reported in the literature. Second, it has been found that an initially stable plasma, satisfying the Kadomtsev criteria, and with a small initial pressure perturbation in the axial direction, remains stable all through the compression phase, even though there are large changes in the pressure and magnetic field levels. Third, a plasma that violates the Kadomtsev criteria, even by a small amount, turns out to be unstable, as predicted by theory. In practical terms, this means that it is preferable to stay well away from the stability limit, even at the cost of some reduction of initial plasma pressure. Fourth, even during the burn phase, when there is a large and rapid increase in plasma pressure due to fusion energy deposition, an initially stable plasma generally tends to remain stable, and even improves its stability margin. This observation shows that the inverse Z pinch is fairly benign as a MTF target, as an initially stable plasma remains stable during both the compression and burn phases. Fifth, certain unusual features are observed in the temperature profile--these depend upon the time scale for implosion. This has implications for plasma-surface interactions at the liner and central conductor.

  16. High Power Gas Lasers

    NASA Astrophysics Data System (ADS)

    Seelig, W.

    1984-03-01

    A brief survey is given of the trends in the development of high power gas lasers for industrial applications. The properties of laser media, problems of beam quality, and short wavelength performance of high power gas lasers are considered.

  17. Optical guidance of terrawatt laser pulses by the implosion phase of a fast Z-pinch discharge in a gas-filled capillary.

    PubMed

    Hosokai, T; Kando, M; Dewa, H; Kotaki, H; Kondo, S; Hasegawa, N; Nakajima, K; Horioka, K

    2000-01-01

    A new method of optical guidance by the implosion phase of a fast Z-pinch discharge in a gas-filled capillary is proposed. An imploding plasma column has a concave electron-density profile in the radial direction, just before a stagnation phase driven by a converging current sheet and a shock wave. The feasibility of optical guidance of a high-intensity (>1 x 10(17) W/cm(2)) Ti:sapphire laser pulse by use of this method over a distance of 2 cm, corresponding to 12.5 times the Rayleigh length, has been experimentally demonstrated. The guiding-channel formation process was directly probed with a He-Ne laser beam. The electron density in the fully ionized channel was estimated to be 2.0 x 10(17) cm(-3) on the axis and 7.0 x 10(17) cm(-3) on the peaks of the channel edge, with a diameter of 70 mum, as indicated by the experimental results, which were corroborated by a magnetohydrodynamics simulation. PMID:18059765

  18. Spatially-Resolved Argon and Neon K-Shell X-Ray Spectra from Triple-Nozzle Gas-Puff Z-Pinches on Cobra

    NASA Astrophysics Data System (ADS)

    Qi, Niansheng; de Grouchy, Philip; Hoyt, Cad; Shelkovenko, Tania; Pikuz, Sergei; Atoyan, Levon; Potter, William; Cahill, Adam; Greenly, John; Kusse, Bruce; Hammer, David

    2014-10-01

    We present the x-ray spectra obtained during Ar/Ne gas puff z-pinch experiments on the 1MA, 200ns COBRA pulsed power generator at Cornell University. A triple-nozzle gas-puff, which produces two annular (``outer'' and ``inner'') gas puffs and a high density center jet, is used to tailor the radial mass density distribution. Argon and/or neon plasmas are imploded. Filtered x-ray photo-conducting detectors are used for timing the neon and argon K-shell emission and a filtered x-ray pinhole camera images the K-shell x-ray source size. A spectrometer with three spherical mica crystals is used to capture the K-shell x-ray emission. Our objective is to diagnose the Ar and Ne pinch plasma densities (1019-1020 cm-3) and temperatures (0.5-2 keV) with 0.1 mm axial and/or radial spatial resolution from the K-shell X-ray spectra. The He-like resonance to intercombination line ratio will be used to estimate the electron density and the He-like resonance to Li-like satellite line ratio will be used to estimate the electron temperature. We will also add Cl as a dopant in either the center Ar gas jet or inner annular puff for K-shell x-ray spectrum studies. Work supported by DOE Grant No. DE-NA0001836.

  19. High power fiber lasers

    Microsoft Academic Search

    Qi-Hong Lou; Jun Zhou

    2007-01-01

    In this review article, the development of the double cladding optical fiber for high power fiber lasers is reviewed. The\\u000a main technology for high power fiber lasers, including laser diode beam shaping, fiber laser pumping techniques, and amplification\\u000a systems, are discussed in detail. 1050 W CW output and 133 W pulsed output are obtained in Shanghai Institute of Optics and

  20. 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., E-mail: mitrofan@triniti.ru; Grabovski, E. V.; Gritsuk, A. N.; Laukhin, Ya. N.; Aleksandrov, V. V.; Oleinik, G. M.; Medovshchikov, S. F. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)] [Troitsk Institute for Innovation and Fusion Research (Russian Federation); Shevel'ko, A. P. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    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 the outer agar-agar foam cascade was 10-40 eV. During the implosion of foam-wire loads at currents of up to 3 MA, SXR pulses (h{nu} > 100 eV) with a duration of 10 ns and peak power of 3 TW were detected. It is shown that the temporal profile of single-peak and double-peak SXR pulses can be controlled by varying the parameters of the outer and inner cascades of the foam-wire load.

  1. 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. (Kurchatov Institute, Moscow, Russia); 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 demonstrated at the SNL Z-IFE LTD laboratory with rep-rates up to 10.3 seconds between shots (this is essentially at the goal of 10 seconds for Z-IFE). (7) A single LTD switch at Tomsk was fired repetitively every 12 seconds for 36,000 shots with no failures. (8) Five 1.0 MA, 100 kV, 100 ns, LTD cavities have been combined into a voltage adder configuration with a test load to successfully study the system operation. (9) The combination of multiple LTD coaxial lines into a tri-plate transmission line is examined. The 3D Quicksilver code is used to study the electron flow losses produced near the magnetic nulls that occur where coax LTD lines are added together. (10) Circuit model codes are used to model the complete power flow circuit with an inductive isolator cavity. (11) LTD architectures are presented for drivers for Z-IFE and high yield. A 60 MA LTD driver and a 90 MA LTD driver are proposed. Present results from all of these power flow studies validate the whole LTD/RTL concept for single-shot ICF high yield, and for repetitive-shot IFE.

  2. X-ray emission from z pinches at 10 7 A: current scaling, gap closure, and shot-to-shot fluctuations.

    PubMed

    Stygar, W A; Ives, H C; Fehl, D L; Cuneo, M E; Mazarakis, M G; Bailey, J E; Bennett, G R; Bliss, D E; Chandler, G A; Leeper, R J; Matzen, M K; McDaniel, D H; McGurn, J S; McKenney, J L; Mix, L P; Muron, D J; Porter, J L; Ramirez, J J; Ruggles, L E; Seamen, J F; Simpson, W W; Speas, C S; Spielman, R B; Struve, K W; Torres, J A; Vesey, R A; Wagoner, T C; Gilliland, T L; Horry, M L; Jobe, D O; Lazier, S E; Mills, J A; Mulville, T D; Pyle, J H; Romero, T M; Seamen, J J; Smelser, R M

    2004-04-01

    We have measured the x-ray power and energy radiated by a tungsten-wire-array z pinch as a function of the peak pinch current and the width of the anode-cathode gap at the base of the pinch. The measurements were performed at 13- and 19-MA currents and 1-, 2-, 3-, and 4-mm gaps. The wire material, number of wires, wire-array diameter, wire-array length, wire-array-electrode design, normalized-pinch-current time history, implosion time, and diagnostic package were held constant for the experiments. To keep the implosion time constant, the mass of the array was increased as I2 (i.e., the diameter of each wire was increased as I), where I is the peak pinch current. At 19 MA, the mass of the 300-wire 20-mm-diam 10-mm-length array was 5.9 mg. For the configuration studied, we find that to eliminate the effects of gap closure on the radiated energy, the width of the gap must be increased approximately as I. For shots unaffected by gap closure, we find that the peak radiated x-ray power P(r) proportional to I1.24+/-0.18, the total radiated x-ray energy E(r) proportional to I1.73+/-0.18, the x-ray-power rise time tau(r) proportional to I0.39+/-0.34, and the x-ray-power pulse width tau(w) proportional to demonstrate that the internal energy and radiative opacity of the pinch are not responsible for the observed subquadratic power scaling. Heuristic wire-ablation arguments suggest that quadratic power scaling will be achieved if the implosion time tau(i) is scaled as I(-1/3). The measured 1sigma shot-to-shot fluctuations in P(r), E(r), tau(r), tau(w), and tau(i) are approximately 12%, 9%, 26%, 9%, and 2%, respectively, assuming that the fluctuations are independent of I. These variations are for one-half of the pinch. If the half observed radiates in a manner that is statistically independent of the other half, the variations are a factor of 2(1/2) less for the entire pinch. We calculate the effect that shot-to-shot fluctuations of a single pinch would have on the shot-success probability of the double-pinch inertial-confinement-fusion driver proposed by Hammer et al. [Phys. Plasmas 6, 2129 (1999)]. We find that on a given shot, the probability that two independent pinches would radiate the same peak power to within a factor of 1+/-alpha (where 0< or =alpha<1) is equal to erf(alpha/2sigma), where sigma is the 1sigma fractional variation of the peak power radiated by a single pinch. Assuming alpha must be < or =7% to achieve adequate odd-Legendre-mode radiation symmetry for thermonuclear-fusion experiments, sigma must be <3% for the shot-success probability to be > or =90%. The observed (12/2(1/2))%=8.5% fluctuation in P(r) would provide adequate symmetry on 44% of the shots. We propose that three-dimensional radiative-magnetohydrodynamic simulations be performed to quantify the sensitivity of the x-ray emission to various initial conditions, and to determine whether an imploding z pinch is a spatiotemporal chaotic system. PMID:15169102

  3. Implementation of the thermonuclear process in D{sup 3}He-{sup 9}Be plasma on the basis of a Z pinch with an ultrafast laser ignition

    SciTech Connect

    Voronchev, V. T., E-mail: voronchev@srd.sinp.msu.ru; Kukulin, V. I. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2010-01-15

    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 D{sup 3}He fuel contained under a high pressure inside a sealed cylindrical capsule made from metallic {sup 9}Be. 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 D{sup 3}He 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 D{sup 3}He-{sup 9}Be 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 {sup 3}He(d, {gamma}), D(d, {gamma}), and {sup 3}He({sup 3}He, {gamma}) naturally accompanying the burning of the D{sup 3}He fuel are shown to serve as a convenient diagnostic tool. A nuclear 'marker' of D{sup 3}He fusion on the basis of the detection of monochromatic gamma rays produced in the reaction {sup 9}Be({alpha}, {gamma}n), which is induced in the liner beryllium shell by energetic fusion alpha particles, is also examined.

  4. 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. [Centre d'Etudes de Gramat, BP 80200 46500 Gramat (France)

    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.

  5. 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.

  6. 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.

  7. High power arcjet

    NASA Technical Reports Server (NTRS)

    Auweter-Kurtz, M.; Glocker, B.; Goelz, T. M.; Habiger, H.; Kurtz, H. L.; Schrade, H. O.; Wegmann, T.

    1990-01-01

    The activities on the development of the high power arc jet HIPARC, the thrust balance, and plasma diagnostic probes are discussed. Modifications of the HIPARC design and a synopsis of the materials used are given. Further experimental results with the TT30 thruster in the 50 kW range are presented. Some first calibration measurements of the thrust balance are also included. Progress concerning the development of plasma diagnostic devices is documented.

  8. 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.

  9. High power microwave generator

    DOEpatents

    Ekdahl, Carl A. (Albuquerque, NM)

    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.

  10. High power arcjet

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    The activities of the High Power Arcjet Project (HIPARC) from August 1990 to January 1991 are discussed. In this period the HIPARC thruster was ignited for the first time. Power levels up to 140 kW with a mass flow rate of 300 mg/s hydrogen were reached. Specific impulse values of more than 1300 s were shown to be possible. Tests were performed with the baseline thruster version only, which has a 6 mm throat diameter and a conical nozzle with a 20 degree half angle. Measurement data summing up all tests carried out until now is included. All measuring methods are described, including a check on possible error sources.

  11. 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.

  12. 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.

  13. High power connection system

    DOEpatents

    Schaefer, Christopher E. (Warren, OH); Beer, Robert C. (Noblesville, IN); McCall, Mark D. (Youngstown, OH)

    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.

  14. 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.

  15. POST-IRRADIATION PROPERTIES OF CANDIDATE MATERIALS FOR HIGH POWER TARGETS

    E-print Network

    McDonald, Kirk

    ON: Mechanical Properties Strength Ductility Fracture Toughness Physical Properties Thermal combining good properties of Be and Aluminum. Nickel-plated Aluminum (NUMI horn): Assess how bonding betweenPOST-IRRADIATION PROPERTIES OF CANDIDATE MATERIALS FOR HIGH POWER TARGETS H. Kirk, N. Simos, P

  16. Alpha high-power chemical laser program

    NASA Astrophysics Data System (ADS)

    Ackerman, Richard A.; Callahan, David; Cordi, Anthony J.; Lurie, Henry; Thomson, Matthew

    1995-03-01

    Alpha is a megawatt-class hydrogen fluoride, continuous wave, space based chemical laser brassboard which demonstrates and validates technology for space-based applications. It consists of a cylindrical gain generator that exhausts radially outward through circumferential nozzles forming an annular lasing media and an annular ring resonator, which extracts the laser energy. Technical innovations first demonstrated on Alpha include: (1) use of extruded aluminum components, (2) diamond turned, annular optics made of molybdenum, (3) uncooled silicon mirrors, (4) light weight optical benches, and (5) active alignment. Alpha first lased in 1989, and has repeatably demonstrated megawatt-class power and excellent beam quality. Using Alpha, TRW has demonstrated the use of low weight uncooled mirrors in very high power lasers to reduce system jitter. They have performed flawlessly and beam jitter levels were significantly reduced.

  17. Compact, high power capacitor charger

    Microsoft Academic Search

    M. GiesselmannS; T. Heeren; T. Helle

    2003-01-01

    We are developing compact, high-power chargers for rapid charging of energy storage capacitors. The main application is presently rapid charging of the capacitors inside of compact Marx generators for reprated operation. Compact Marx generators produce output pulses with amplitudes above 300 kV with ns or subns rise-times. A typical application is the generation of high power microwaves. Initially all energy

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

    PubMed

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

    2011-09-01

    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 (10 ?10) crystal and Mica (002) crystal are designed, respectively, to image the Al Ly(?2) line (1727.7 eV) emission and Al He(?) intercombination line (1588.3 eV) emission. The primary experimental data corresponding to these two configurations are presented and discussed. PMID:21974579

  19. Progress in symmetric ICF capsule implosions and wire-array z-pinch source physics for double-pinch-driven hohlraumsThis paper is based on an invited talk given by M K Matzen at the 32nd EPS Conference on Plasma Physics (Tarragona, Spain, 2005)

    Microsoft Academic Search

    M E Cuneo; R A Vesey; G R Bennett; D B Sinars; W A Stygar; E M Waisman; J L Porter; P K Rambo; I C Smith; S V Lebedev; J P Chittenden; D E Bliss; T J Nash; G A Chandler; B B Afeyan; E P Yu; R B Campbell; R G Adams; D L Hanson; T A Mehlhorn; M K Matzen

    2006-01-01

    Over the last several years, rapid progress has been made evaluating the double-z-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough to drive a high yield ICF capsule. The secondary hohlraum is irradiated

  20. 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.

  1. High power microwave source development

    Microsoft Academic Search

    James N. Benford; Gabriel Miller; Seth Potter; Steve Ashby; Richard R. Smith

    1995-01-01

    The requirements of this project have been to: (1) improve and expand the sources available in the facility for testing purposes and (2) perform specific tasks under direction of the Defense Nuclear Agency about the applications of high power microwaves (HPM). In this project the HPM application was power beaming. The requirements of this program were met in the following

  2. High power gas laser amplifier

    SciTech Connect

    Leland, W.T.; Stratton, T.F.

    1981-04-28

    A high power output CO/sub 2/ gas laser amplifier is described that has 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.

  3. High power gas laser amplifier

    DOEpatents

    Leland, Wallace T. (Los Alamos, NM); Stratton, Thomas F. (Los Alamos, NM)

    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.

  4. 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.

  5. 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.

  6. Advances in high-power targets

    Microsoft Academic Search

    H. G. Kirk

    2007-01-01

    High-power targets are a major issue for both neutron sources and neutrino factories. This paper reviews the status of international studies. The targetry R&D program required to realize high-power targets is described.

  7. High power broadband millimeter wave TWTs

    Microsoft Academic Search

    Bill G. James

    1999-01-01

    In the early 1980's the requirement for high power broadband millimeter wave sources encouraged the development of microwave vacuum device amplifiers for radar and communication systems. Many government funded programs were implemented for the development of high power broadband millimeter wave amplifiers that would meet the needs of the high power community. The tube design capable of meeting these goals

  8. High power broadband millimeter wave TWTs

    Microsoft Academic Search

    Bill G. James

    1999-01-01

    In the early 1980’s the requirement for high power broadband millimeter wave sources encouraged the development of microwave vacuum device amplifiers for radar and communication systems. Many government funded programs were implemented for the development of high power broadband millimeter wave amplifiers that would meet the needs of the high power community. The tube design capable of meeting these goals

  9. High Power Broadband Millimeter Wave TWTs

    Microsoft Academic Search

    Bill G. James

    1998-01-01

    In the early 1980's the requirement for high power broadband millimeter wave sources encouraged the development of microwave vacuum device amplifiers for radar and communication systems. Many government funded programs were implemented for the development of high power broadband millimeter wave amplifiers that would meet the needs of the high power community. The tube design capable of meeting these goals

  10. High power rechargeable batteries Paul V. Braun

    E-print Network

    Braun, Paul

    emerging concepts in high power batteries, with a particular focus on Li-ion based chemistries. Ó 2012 storage Secondary batteries High energy density High power density Lithium ion battery 3D batteryHigh power rechargeable batteries Paul V. Braun , Jiung Cho, James H. Pikul, William P. King

  11. Argon z-pinch implosions on Phoenix

    SciTech Connect

    Fisher, A.; Peterson, G. [Naval Research Lab., Washington, DC (United States); Nolting, E. [Naval Surface Warfare Center, Silver Spring, MD (United States)] [and others

    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.

  12. High-Power Rf Load

    DOEpatents

    Tantawi, Sami G. (San Mateo, CA); Vlieks, Arnold E. (Livermore, CA)

    1998-09-01

    A compact high-power RF load comprises a series of very low Q resonators, or chokes [16], in a circular waveguide [10]. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer [12] at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications. The design is easily scalable to other RF frequencies and adaptable to the use of other lossy materials.

  13. High Power Helicon Propulsion Experiments

    NASA Astrophysics Data System (ADS)

    Ziemba, Timothy; Slough, John; Winglee, Robert

    2005-02-01

    The High Power Helicon (HPH) under development at the University of Washington may have an attractive application as an electrode-less in-space thruster. Output plasma characteristics show that plasma is created in and near the helicon coil and is accelerated by a helicon induced axial potential downstream away from the HPH. The bulk acceleration of the plasma is believed to be due to a coupling of the plasma electrons to the helicon field, which in turn transfers energy to the ions via an ambipolar electric field. Downstream electric potentials of greater than 150 volts having been measured with the amplitude of the electric field being dependent on experimentally controlled parameters. Time of flight measurements of the plasma transiting downstream show specific impulses (Isp) near 2000 seconds for Argon with calculated thrust levels near 1 Newton for input powers to the plasma in the tens of kilowatts. The system is capable of using different neutral gases as propellants with nitrogen and hydrogen having baseline Isp levels of 3000 and 5000 seconds respectfully giving some variability in Isp and thrust by the choice of propellants. Current work focuses on the determination and optimization of the system efficiencies and increasing output power levels.

  14. 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).

  15. Aluminum: Reflective Aluminum Chips

    SciTech Connect

    Recca, L.

    1999-01-29

    This fact sheet reveals how the use of reflective aluminum chips on rooftops cuts down significantly on heat absorption, thus decreasing the need for air conditioning. The benefits, including energy savings that could reach the equivalent of 1.3 million barrels of oil annually for approximately 100,000 warehouses, are substantial.

  16. High-power gridded tubes—1972

    Microsoft Academic Search

    T. E. Yingst; D. R. Carter; J. A. Eshleman; J. M. Pawlikowski

    1973-01-01

    The technology described in this paper is intended to update the reader about the last decade of research and development in the field of high-power gridded tubes. Lower power level tubes are also discussed to serve as a foundation for the high-power tubes because they are generally used for drive stages. Special emphasis is placed on the development of a

  17. High-power transmitters for radar applications

    Microsoft Academic Search

    Meppalli K. Shandas

    2009-01-01

    High-power transmitters are one of the critical elements in a radar system. The radar waveform needs to be amplified without distortion to the desired output power level by the high-power transmitter. In addition to affecting the overall performance of the radar system, the design of the transmitter affects many other factors, such as size, weight, power consumption, operating cost, reliability

  18. Characterization of high-power lasers

    NASA Astrophysics Data System (ADS)

    Slater, John M.; Edwards, Brian

    2010-04-01

    This paper discusses methods for characterization of high power lasers. Specifically, these methods have been developed for the High Energy Laser Joint Technology Office and used for independent, government-sponsored testing in the 25 and 100 kW phases of the Joint High Power Solid State Laser program. Primarily this paper addresses measurement of power and beam quality.

  19. RECENT DEVELOPMENTS IN PULSED HIGH POWER SYSTEMS

    Microsoft Academic Search

    David E. Anderson

    2010-01-01

    Pulsed power systems are inherent in any high power accelerator system. Applications include, among others, modulators for powering high power klystrons, pulsed power systems to drive linear induction accelerating cells, kicker magnet drivers for storage rings, and a wide variety of beam deflection and pulsed focusing systems. As with many enabling technologies, component limitations and materials properties dominate the engineering

  20. 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.

  1. Experimental program for investigation of high power density MHD

    NASA Astrophysics Data System (ADS)

    Lineberry, J. T.; Schmidt, H. J.; Chapman, J. N.

    Research on magnetohydrodynamic (MHD) power generation, directed at the proof-of-concept of combustion MHD as a viable source for use with space-based weapons systems, is described. Currently, small-scale laboratory evaluations of a solid-aluminum, carbon-fueled hybrid combustor are being completed. Ultimate plans for this research include coupling of this combustor to an MHD generator to demonstrate high power density in the laboratory. This report includes experimental results from the initial hybrid combustor tests. The design of this combustor system and its design point are detailed. Experimental data from firings are presented and analyzed. The burn or regression rate for this fuel is summarized. The combustor tests have been successful; the design point for this system was readily achieved and sustained.

  2. Diffuse reflectivity of gold plating with high power laser irradiation

    NASA Astrophysics Data System (ADS)

    Wu, Yong; Zhang, Lei; Yang, Pengling; Wang, Zhenbao; Tao, Mengmeng; Liu, Fuhua; Feng, Guobin

    2015-05-01

    The discoloration and optical characteristics of the gold plating film under long-time high power laser irradiation are investigated. The fabrication process of gold plating on nickel underplate on rough surface of copper and aluminum alloy substrates is introduced. The measurement results of the diffuse reflectivity for the samples with different surface roughness indicate that roughness of the gold layer surface should be 4?m to obtain the maximum value of diffuse reflectivity. The discoloration and variation of diffuse reflectivity are experimentally studied under 2000W irradiation. The research results show that the discoloration and degrading of reflectivity are caused by the diffusion of Ni to the gold plating surface and forming NiO thin film due to the porosity of the gold film and high temperature treatment. A change of diffuse reflectivity related mechanism is described. Several plating solution recipes are used to eliminate the discoloration and mitigate the degrading of the reflectivity on gold surface.

  3. 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.

  4. 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.

  5. Research on high power microwave weapons

    Microsoft Academic Search

    Guoqi Ni; Benqing Gao; Junwei Lu

    2005-01-01

    This article describes for high power microwave (abbreviation HPM) weapons research from its procedures and developing trends. In the process of researching, developing and using weapons, we have been seeking a real \\

  6. 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.

  7. High-power laser projection displays

    Microsoft Academic Search

    Guenter Hollemann; Bernhard Braun; Peter Heist; Jan Symanowski; Ulf Krause; Juergen Kraenert; Christhard Deter

    2001-01-01

    In this paper recent research on high-power laser displays for large display applications is reported. We discuss our compact high-power red-green-blue laser system for use as a light source based on a passively mode-locked solid-state laser with an optical parametric oscillator and sum- frequency mixing with very high efficiency and 19 W of white light. Concepts for power scaling to

  8. High power laser apparatus and system

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.; Brandhorst, H. W., Jr. (inventors)

    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.

  9. Laser surface alloying of silicon into aluminum casting alloys

    Microsoft Academic Search

    Zhiyue Xu; Keng H. Leong; Paul G. Sanders

    2000-01-01

    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:yttrium-aluminum-garnet laser with fiber-optic beam delivery was used

  10. High Power Co-Axial Coupler

    SciTech Connect

    Neubauer, M. [Muons, Inc.; Dudas, A. [Muons, Inc.; Rimmer, Robert A. [JLAB; Guo, Jiquan [JLAB; Williams, R. Scott [JLAB

    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.

  11. Aluminum Boats

    NSDL National Science Digital Library

    2012-06-26

    Test the buoyancy of an aluminum foil boat and an aluminum foil ball. Why does the same material in different shapes sink or float? This activity explores the fact that the amount of water pushed aside by an object equals the force of water pushing upward on the object.

  12. 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.

  13. A high power linear solid state pulser

    Microsoft Academic Search

    Boris Yen; Brent Davis; Rex Booth

    1999-01-01

    Particle accelerators usually require high voltage and high power. Typically, the high voltage\\/power generation utilizes a topology with an energy store and switching mechanisms to extract that stored energy. The switches may be active or passive devices. Active switches are hard or soft vacuum tubes, or semiconductors. When required voltages exceed tens of kilovolts, numerous semiconductors are stacked to withstand

  14. Use of high power microwave weapons

    Microsoft Academic Search

    E. Van Keuren; J. Knighten

    1995-01-01

    The destructive power of high power microwave (HPM) generators allow them to be used as effective weapons by both law enforcement and criminal organizations. Now, with the desperate need for cash by some developing nations, devices such as relativistic magnetrons, capable of producing multi-megawatts and for use in weapons, have been offered for sale to other nations, groups, and individuals.

  15. Spurious oscillations in high power klystrons

    Microsoft Academic Search

    B. Krietenstein; K. Ko; T. Lee; U. Becker; T. Weiland; M. Dohlus

    1995-01-01

    Spurious oscillations in high power klystrons are found to occur in the gun region, in the cavities in the main body of the tube, or in the drift tunnel. The criteria that determine whether a mode will oscillate is that its beam loading be negative, and that the power it extracts from the beam exceeds its losses to external loading

  16. Spurious oscillations in high power klystrons

    Microsoft Academic Search

    B. Krietenstein; K. Ko; T. Lee; U. Becker; T. Weiland; M. Dohlus

    1996-01-01

    Spurious oscillations in high power klystrons are found to oc- cur in the gun region, in the cavities in the main body of the tube, or in the drift tunnel. The criteria that determine whether a mode will oscillate is that its beam loading be negative, and that the power it extracts from the beam exceeds its losses to exter-

  17. Dispenser cathode high power gridded klystron gun

    Microsoft Academic Search

    R. B. True; M. F. Kirshner; L. Turek; G. R. Good; R. J. Hansen; T. M. Bemis; R. J. Bartkowski

    2004-01-01

    This paper describes the design and performance of a new shadow gridded gun useful for high power radar klystrons. The gun features an M-type dispenser cathode having heater power identical to a larger diameter cathode oxide cathode gun used in one application. It is known that dispenser cathodes are more tolerant of arcs, poisoning, and other effects that can ruin

  18. High power fiber optic laser beam delivery

    Microsoft Academic Search

    K. H. Leong; B. V. Hunter

    1996-01-01

    Fiber-optic beam delivery is commonly used on industrial laser systems. This article examines the conditions for the optimal propagation of high power beams through optical fibers. Beam quality effects by step and gradient index fibers of different lengths are considered. The differences between the diverging beam from a fiber and the beam at focus and on the fiber face are

  19. High Power Lasers... Another approach to

    E-print Network

    1 High Power Lasers... Another approach to Fusion Energy John Sethian Plasma Physics Division Naval Research Laboratory Washington, DC #12;2 Main points of the talk Fusion Energy based on lasers and direct drive targets Can lead to an attractive electricity generating power plant Developing Laser Fusion

  20. Helical antennas for high powered RF

    Microsoft Academic Search

    J. R. Mayes; M. G. Mayes; W. C. Nunnally; C. W. Hatfield

    2009-01-01

    Radiating high power RF below 1 GHz can be difficult. Large structures are preferred for high voltage operation; however, large structures are difficult to deploy. Conversely, small geometries are more easily deployed, but insulating the high voltage can be difficult. Dipole structures have made their way into use due to the relatively simple and compact implementation; however, their radiation pattern

  1. High power solid state switch module

    Microsoft Academic Search

    H. Sanders?; S. Glidden

    2004-01-01

    A high voltage, high di\\/dt, solid state switch module has been developed. This compact module can be used to replace thyratrons in high power modular applications. The module contains multiple silicon thyristors packaged in a low inductance series configuration with a strip-line output connection. A self powered gate drive is triggered by a 15 V, 1 A pulse. Each module

  2. High power microwave generation with pulse compression

    Microsoft Academic Search

    A. W. Biggs

    1995-01-01

    Chirped pulse compression is achieved in transmit modes with wideband antennas, such as log periodic dipole arrays (LPDA), where the matched filters are the antennas. In this paper, a modulation technique is described which compresses ultra wideband (UWB) signals on conventional LPDAs. In transmit modes, high power microwaves (HPM) applications are found with wideband transmitting antennas, such as LPDA, where

  3. High-power VCSEL systems and applications

    NASA Astrophysics Data System (ADS)

    Moench, Holger; Conrads, Ralf; Deppe, Carsten; Derra, Guenther; Gronenborn, Stephan; Gu, Xi; Heusler, Gero; Kolb, Johanna; Miller, Michael; Pekarski, Pavel; Pollmann-Retsch, Jens; Pruijmboom, Armand; Weichmann, Ulrich

    2015-03-01

    Easy system design, compactness and a uniform power distribution define the basic advantages of high power VCSEL systems. Full addressability in space and time add new dimensions for optimization and enable "digital photonic production". Many thermal processes benefit from the improved control i.e. heat is applied exactly where and when it is needed. The compact VCSEL systems can be integrated into most manufacturing equipment, replacing batch processes using large furnaces and reducing energy consumption. This paper will present how recent technological development of high power VCSEL systems will extend efficiency and flexibility of thermal processes and replace not only laser systems, lamps and furnaces but enable new ways of production. High power VCSEL systems are made from many VCSEL chips, each comprising thousands of low power VCSELs. Systems scalable in power from watts to multiple ten kilowatts and with various form factors utilize a common modular building block concept. Designs for reliable high power VCSEL arrays and systems can be developed and tested on each building block level and benefit from the low power density and excellent reliability of the VCSELs. Furthermore advanced assembly concepts aim to reduce the number of individual processes and components and make the whole system even more simple and reliable.

  4. MATERIAL RESPONSE TO HIGH POWER BEAMS

    E-print Network

    McDonald, Kirk

    MATERIAL RESPONSE TO HIGH POWER BEAMS GORAN [KORO UKNF Target Studies Web Page: http://hepunx.rl.ac.uk/uknf/wp3/ #12;The main issue for the materials (solids) used in the target systems (targets, beam windows pulse length decreases, the estimate of material strength and corresponding lifetime based on simple

  5. High Power Hg Target Conceptual Design Review

    E-print Network

    McDonald, Kirk

    and secondary containments have air at 1 atmosphere - Air activation is not an issue since the air is not purged after each pulse and 1 hour of waiting is sufficient for decay - May require cartridge filtration like, but ... · Base support structure may be fabricated from painted carbon steel or aluminum · Gaskets shall be non

  6. 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)

  7. High Power Disk Loaded Guide Load

    SciTech Connect

    Farkas, Z.D.; /SLAC

    2006-02-22

    A method to design a matching section from a smooth guide to a disk-loaded guide, using a variation of broadband matching, [1, 2] is described. Using this method, we show how to design high power loads. The load consists of a disk-loaded coaxial guide operating in the TE{sub 01}-mode. We use this mode because it has no electric field terminating on a conductor, has no axial currents, and has no current at the cylinder-disk interface. A high power load design that has -35 dB reflection and a 200 MHz, -20 dB bandwidth, is presented. It is expected that it will carry the 600 MW output peak power of the pulse compression network. We use coaxial geometry and stainless steel material to increase the attenuation per cell.

  8. 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.

  9. Thermal properties of high-power transistors

    Microsoft Academic Search

    R. H. Winkler

    1967-01-01

    The temperature of a transistor can be determined from the emitter-base voltage versus collector-current characteristic. This characteristic was used for studying the stability of parallel pairs of high-frequency high-power transistors. The thermal effect may cause the incremental emitter-base resistance to assume a negative value. This, in turn, will cause the current flow in a pair of transistors to be asymmetrical.

  10. High-power, high-efficiency FELs

    SciTech Connect

    Sessler, A.M.

    1989-04-01

    High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs.

  11. Highly power-efficient quantum cascade lasers

    Microsoft Academic Search

    Peter Q. Liu; Anthony J. Hoffman; Matthew D. Escarra; Kale J. Franz; Jacob B. Khurgin; Yamac Dikmelik; Xiaojun Wang; Jen-Yu Fan; Claire F. Gmachl

    2010-01-01

    Quantum cascade lasers are promising mid-infrared semiconductor light sources for molecular detection in applications such as environmental sensing or medical diagnostics. For such applications, researchers have been striving to improve device performance. Recently, improvements in wall plug efficiency have been pursued with a view to realizing compact, portable, power-efficient and high-power quantum cascade laser systems. However, advances have largely been

  12. 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.

  13. High Power Helicon 2 (HPH2)

    Microsoft Academic Search

    James Prager

    2005-01-01

    The high power helicon source, developed at the University of Washington and MSNW, is capable of depositing up to 100 kW of peak power into the plasma. High input powers are obtained using a low impedance, solid state switching power supply, which produces peak oscillating antenna currents up to 2.4 kA. Typical operational frequencies are from 0.3 to 1.1 MHz

  14. Antenna coupling for high power microwave tubes

    Microsoft Academic Search

    Vishnu Srivastva

    2010-01-01

    Microwave tubes are used for generation and amplification of high power (up to MW of pulsed\\/CW output power) and high frequency (0.3GHz to 1000GHz) electromagnetic waves. These tubes are in great demands for defense, communication, remote sensing, and for numerous industrial, scientific, and medical (ISM) applications. Input and output RF couplings in microwave tubes are very significant for efficient and

  15. Space applications of high power microwaves

    Microsoft Academic Search

    James Benford

    2007-01-01

    A variety of methods have been suggested for transferring energy from Earth-to-space, space-to-Earth, and space-to-space using high power microwave beams. All use power beaming. Microwave beams have been studied for propelling spacecraft for launch to orbit, orbit raising, launch from orbit into interplanetary and interstellar space and deployment of large space structures. The microwave thermal rocket, called the ‘microwave thermal

  16. Space Applications of High-Power Microwaves

    Microsoft Academic Search

    James Benford

    2008-01-01

    Schemes have been suggested for transferring energy from Earth-to-space, space-to-Earth, and space-to-space using high-power microwave (HPM) beams. All use power beaming. Microwave beams have been studied for propelling spacecraft for launch to orbit, orbit raising, launch from orbit into interplanetary and interstellar space, and deployment of large space structures. The microwave thermal rocket, called the ldquomicrowave thermal thruster,rdquo is a

  17. 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.

  18. Opportunities in high-power fiber lasers

    NASA Astrophysics Data System (ADS)

    Sahu, Jayanta K.; Kim, Jaesun; Yoo, Seongwoo; Webb, Andrew; Codemard, Christophe; Dupriez, Pascal; Jeong, Yoonchan; Nilsson, Johan; Richardson, David; Payne, David N.

    2006-10-01

    Fiber lasers and amplifiers offer unique characteristics that are derived from the use of a waveguide and the properties of rare-earth doped silica glass. Their capability for high output power, with high efficiency, has been demonstrated both in CW and pulsed regimes. Cladding-pumped Yb-doped fiber lasers have now reached beyond kW levels with good beam quality. Advances in both fiber technology and high-power multimode diode pump sources, and the inherent power scalability of cladding-pumped fibers, lie behind this power surge. However, there are still many challenges to overcome in the high-power fiber laser area. These include, for example, single-mode output at higher powers and power scaling of a three-level laser. This paper reviews novel W-type fiber and depressed clad hollow optical fiber waveguide structures designed with distributed wavelength filter characteristics to achieve an efficient and high power cladding-pumped three-level lasers such as Nd-doped fiber laser operating at 930 nm and Yb-doped fiber laser at 980 nm. Moreover, such fiber geometries enable to scale up the output power in a small and single-mode core for generating a single-mode output beam in a robust and reliable manner.

  19. 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

  20. Alpha high-power chemical laser program

    NASA Astrophysics Data System (ADS)

    Cordi, Anthony J.; Lurie, Henry; Callahan, David W.; Thomson, Matthew

    1993-06-01

    Alpha is a megawatt-class ground demonstration of a hydrogen fluoride, continuous wave, space-based chemical laser. The laser operates in the infrared at 2.8 microns. The basic device consists of a cylindrical combustion chamber that exhausts radially outward through circumferential nozzles into an annular lasing area. An annular ring resonator is used to extract the laser energy from this area. Technical firsts include: (1) use of aluminum combustion chamber/nozzle ring modules, (2) diamond turned, water-cooled optics made of molybdenum for low thermal distortion with good heat transfer, (3) use of uncooled silicon mirrors in a megawatt-class laser system, (4) an optical bench made of aluminum honeycomb, and (5) active controls to adjust alignment of selected mirrors and the optical bench.

  1. 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 2? solid angle. 2.0 W EUV radiation is generated at 13.5 nm in 2? 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 discharge pre-ionization. Prototype commercial gas discharge sources with an EUV power of 35W in 2? sr were already delivered for integration into EUV microsteppers. These sources are equipped with a debris-filter which results in an optics lifetime exceeding 100 million discharges at 1 kHz repetition frequency. The same lifetime was achieved for the components of the discharge system itself. The progress in the development of high-power discharge sources resulted in an EUV power of 150 W in continuous operation at 4.5 kHz repetition rate by implementation of porous metal cooling technology. The EUV plasma has a FWHM-diameter of 0.5 mm and a FWHM-length of 1.5 mm. The intermediate focus power is calculated to be in the range of 15 W - 20 W, depending somewhat on the transmission of the optical path to the intermediate focus and on the etendue specification. The typical fluctuations of the EUV energy are standard deviation ?<5% without any active stabilization. Discharge sources with Sn as emitter were investigated as more efficient alternative to Xenon. Estimates regarding Sn sources reveal the potential of achieving 65 W intermediate focus power by using developed porous metal cooling technology. Improvement of cooling could open the path to 115 W of power for high volume manufacturing using EUV lithography. However, Sn-sources are technologically risky und much less advanced than Xe sources, since fuel-handling and debris mitigation is much more challenging in comparison to Xe-sources. GDPP and LPP sources still compete for the technology of high volume manufacturing sources for EUV lithography. Optimization potential of the etendue of the optical system of EUV scanners will certainly influence any technology decision for HVM sources.

  2. 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.

  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 fiber optic laser beam delivery.

    SciTech Connect

    Leong, K. H.; Hunter, B. V.; Technology Development

    1996-05-01

    Fiber-optic beam delivery is commonly used on industrial laser systems. This article examines the conditions for the optimal propagation of high power beams through optical fibers. Beam quality effects by step and gradient index fibers of different lengths are considered. The differences between the diverging beam from a fiber and the beam at focus and on the fiber face are illustrated. Estimates are provided of the worst-case beam quality to be expected from fibers. Guidelines are also provided for the selection of beam delivery components based on the limitations of the optical system and the tasks to be performed.

  5. 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.

  6. High Power Third Gyroharmonic Frequency Multiplier

    NASA Astrophysics Data System (ADS)

    Lapointe, M. A.; Ganguly, A. K.; Hirshfield, J. L.; Wang, Changbiao; Yoder, R. B.; Wang, Mei

    1998-11-01

    A high power freqeuncy multplier which uses a cyclotron autoresonance accelerator (CARA)(M.A. LaPointe, R.B. Yoder, Changbiao Wang, A.K. Ganguly and J.L. Hirshfield, Phys. Rev. Lett., 76), 2718 (1996) and a third harmonic, TE_311 cavity is being tested. Primary power at 2.856 GHz is used to accelerate a 20--30 A, 75--96kV electron beam up to 320 kV in a CARA. The prepared beam interacts with the TE_311 cavity tuned to the third harmonic of the drive frequency. Simulations show that conversion efficiencies from beam power to microwave power can be as high as 48% producing up to 4.5 MW of 8.568 GHz power. Experiments to date have shown under certain conditions only third harmonic radiation has been generated with a FWHM of 350 kHz, the Fourier limit for the length of the radiation pulse. High power experiments are underway to measure the efficiency of the device.

  7. High-power transmitters for radar applications

    NASA Astrophysics Data System (ADS)

    Shandas, Meppalli K.

    2009-05-01

    High-power transmitters are one of the critical elements in a radar system. The radar waveform needs to be amplified without distortion to the desired output power level by the high-power transmitter. In addition to affecting the overall performance of the radar system, the design of the transmitter affects many other factors, such as size, weight, power consumption, operating cost, reliability and maintenance. This paper provides basic guidelines for designing a radar transmitter and addresses the critical requirements faced by the hardware designer. Available technologies and recent advances that enable designers to meet these requirements are discussed. Vacuum electron devices and solid state technologies are examined, as well as the design trade-offs that must be considered when selecting the more suitable of the two approaches. Specific devices, such as the Traveling Wave Tube (TWT) and other vacuum electron device-based transmitters, including the Microwave Power Module (MPM), solid state amplifier, Active Electronic Scanned Array (AESA), and a combination of these technologies are discussed in detail. Techniques for achieving the critical requirements of a modern radar system, such as good spectral purity, excellent amplitude and phase stability and very low spurious, are also discussed. In particular, this paper emphasizes the practical design of reliable hardware for achieving high microwave power in the 1 to 40 GHz power range.

  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. 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. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2010-02-15

    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.

  10. Aluminum Pannier

    USGS Multimedia Gallery

    This aluminum pannier was made for the storage of meat, vegetables and other food products. The pannier could be buried in the ground or placed in water in order to keep the contents cool. It was designed by Dr. J. D. Love and made for him in 1945. For transportation, this pannier, along with two re...

  11. 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 chemicals including explosives, and even ionized air produced by nuclear isotopes. From the characteristic resonance frequencies one can understand the underlying physics or chemistry of molecules or atoms.

  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. PMID:21192713

  13. High-Power Options for LANSCE

    SciTech Connect

    Garnett, Robert W. [Los Alamos National Laboratory

    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.

  14. 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.

  15. 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.

  16. 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.

  17. High power 2 MHz passively Q-switched nanosecond Nd:YVO4/Cr4+:YAG 914 nm laser.

    PubMed

    Yu, Xin; Yan, Renpeng; Li, Xudong; Ma, Yufei; Chen, Deying; Yu, Junhua

    2012-05-10

    We report a high-power, high-repetition-rate end-pumped passively Q-switched Nd:YVO4/Cr4+: yttrium aluminum garnet 914 nm laser. The maximum output power of 3.8 W at 914 nm is achieved at 2 MHz with the absorbed pump power of 25.2 W. The highest single pulse energy of a pulsed 914 nm laser reaches 2.3 ?J with a pulse width of 27.1 ns. PMID:22614496

  18. Recycling of automotive aluminum

    Microsoft Academic Search

    Jirang CUI; Hans J. ROVEN

    2010-01-01

    With the global warming of concern, the secondary aluminum stream is becoming an even more important component of aluminum production and is attractive because of its economic and environmental benefits. In this work, recycling of automotive aluminum is reviewed to highlight environmental benefits of aluminum recycling, use of aluminum alloys in automotive applications, automotive recycling process, and new technologies in

  19. High-power Broadband Organic THz Generator

    PubMed Central

    Jeong, Jae-Hyeok; Kang, Bong-Joo; Kim, Ji-Soo; Jazbinsek, Mojca; Lee, Seung-Heon; Lee, Seung-Chul; Baek, In-Hyung; Yun, Hoseop; Kim, Jongtaek; Lee, Yoon Sup; Lee, Jae-Hyeok; Kim, Jae-Ho; Rotermund, Fabian; Kwon, O-Pil

    2013-01-01

    The high-power broadband terahertz (THz) generator is an essential tool for a wide range of THz applications. Here, we present a novel highly efficient electro-optic quinolinium single crystal for THz wave generation. For obtaining intense and broadband THz waves by optical-to-THz frequency conversion, a quinolinium crystal was developed to fulfill all the requirements, which are in general extremely difficult to maintain simultaneously in a single medium, such as a large macroscopic electro-optic response and excellent crystal characteristics including a large crystal size with desired facets, good environmental stability, high optical quality, wide transparency range, and controllable crystal thickness. Compared to the benchmark inorganic and organic crystals, the new quinolinium crystal possesses excellent crystal properties and THz generation characteristics with broader THz spectral coverage and higher THz conversion efficiency at the technologically important pump wavelength of 800?nm. Therefore, the quinolinium crystal offers great potential for efficient and gap-free broadband THz wave generation. PMID:24220234

  20. High-power laser-beam characteristics

    NASA Astrophysics Data System (ADS)

    Isarie, Claudiu; Isarie, Ilie

    2004-06-01

    Applications of high-power lasers are very important, especially for cutting and welding. As it is known, laser-beam characteristics have not constant value in time. So we may have suitable testing methods which allow us to determine the principal beam characteristics. The testing methods have to be very accurate, very efficient and in the same time very short as duration. We must apply a 3-dimensional intensity analysis, to the photonic beam we are studying. The number of industrial applications of lasers is increasing. An important thing is to know the optical characteristics of the laser that we study. Only the complete knowledge of the laser parameters allows controlling the process. For each laser system is very important to know the parameters i.e. their dynamic, in order to establish the correct performances. The correct information about the beam is not always possible to obtain. Various physical models help to understand the behavior of the laser beam. The best is if we have complete quantitative information about the photon beam. The definition of the beam diameter is not standardized. In order to do a comparison between different lasers, it is important to know the method that was applied to determine the beam diameter.

  1. High Power Microwave Production by Gyroharmonic Conversion

    NASA Astrophysics Data System (ADS)

    Lapointe, M. A.; Ganguly, A. K.; Yoder, R. B.; Wang, Changbiao; Hirshfield, J. L.

    1996-11-01

    Recent progress on the production of third and fourth harmonic microwave radiation from a high power, axis-encircling beam will be presented. The 4--10 MW beam is produced by cyclotron autoresonance acceleration (CARA) which is described in detail elsewhere.(M. A. LaPointe, R. B. Yoder, C. Wang, A. K. Ganguly and J. L. Hirshfield, Phys. Rev. Lett. 76), 2718 (1996); J. L. Hirshfield, M. A. LaPointe, A. K. Ganguly, R. B. Yoder and C. Wang, Phys. Plasmas 3, 2163 (1996). The output section consists of an open cylindrical cavity whose radius is beyond cutoff at the third harmonic of the drive frequency in the TE_31 mode but resonant in the TE_41 mode. Results to date have shown strong third harmonic but only weak fourth harmonic output. One explanation for the presence of the third harmonic could be reactive pulling of the TE_31 cutoff by the high current (25--30 A) beam. Descriptions of the output cavities as well as frequency spectra and calorimetric power measurements will be presented.

  2. High Power Helicon (HPH) Plasma Source

    NASA Astrophysics Data System (ADS)

    Ziemba, Timothy; Slough, John; Winglee, Robert

    2004-11-01

    A new high power helicon source has been developed at the University of Washington, which is capable of tens of kilowatts power transfer into the plasma. Current is supplied to a half-helical helicon coil by a low impedance solid state switching supply that drives a series tuned resonant circuit. The helicon coil operates with peak antenna currents of 700 Amps and pulse lengths up to 1 millisecond. The device has operated with several different propellants including argon, nitrogen and hydrogen. Upon plasma breakdown the plasma density rises rapidly within 20 microseconds. Significant antenna loading is observed with the transition to the high-density helicon mode. Experimental results show a peaked density profile near the source region typical of helicon discharges. Electron densities greater than 1x10^20 m-3 have been measured at the source region with electron temperatures from 5 to 15 eV depending on discharge parameters. A large axial electric potential drop of 150 to 170 volts is measured between the plasma source and the downstream plasma. Both time of flight and Mach probe measurements of the downstream plasma indicate a supersonic (Mach 5) axial plasma flow.

  3. High Power Helicon In-Space Thruster

    NASA Astrophysics Data System (ADS)

    Ziemba, Timothy; Slough, John; Winglee, Robert

    2004-11-01

    The High Power Helicon (HPH) under development at the University of Washington has direct application as an electrode-less in-space thruster. Axial and radial plasma probe characteristics show that the plasma is created in and near the helicon coil and is then accelerated in the axial direction downstream away from the HPH. The bulk acceleration of the plasma is believed to be due to a coupling of the plasma electrons to the helicon field, which in turn transfers energy to the ions via an ambipolar electric field with downstream electric potentials of greater than 150 volts having been measured. Time of flight measurements of the plasma transiting downstream show specific impulses near 2000 seconds for Argon with calculated thrust levels near 1 Newton for input powers to the plasma in the tens of kilowatts. Nitrogen and hydrogen propellants have Isp levels of 3000 and 5000 seconds respectfully giving some variability in Isp and thrust level by the choice of propellants. Current work focuses on the determination of the various loss channels and optimization of the system efficiencies at increased output power levels.

  4. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, Lloyd A. (Livermore, CA); Dane, Clifford B. (Livermore, CA)

    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.

  5. 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.

  6. Relaxation of High Power Microwave Surface Plasma

    NASA Astrophysics Data System (ADS)

    Beeson, Sterling; Neuber, Andreas

    2012-10-01

    The electron loss mechanisms related to the relaxation of pulsed rf-generated plasma are investigated. A 3 MW, 3 ?s width, 50 ns risetime high power microwave pulse is transmitted through a dielectric window that terminates a WR-284 (S-band) waveguide filled with insulating gas where the investigated plasma is formed across this window on the atmospheric side. This produces electron densities on the order of 10^14 cm-3 for pressures of 10 to 400 torr in air, N2 and argon environments. This plasma attenuates the pulse on the order of -40 to -10 dB during peak electric field amplitudes. Using a multi-standard waveguide coupler to inject a low power probing signal, the post-pulse attenuation values are measured and used to quantify the temporal evolution of the electron density. This technique is confirmed by means of verifying the attachment rates in an air environment and 2-body recombination rate in a N2 environment. The major recombination processes for high pressure argon plasma are identified, e.g. 3-body recombination becomes dominant within the first few microseconds after pulse termination. The measured rates for recombination are compared with sparsely available data and models from literature in the regime of interest.

  7. 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 ?W 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.

  8. High power THz sources for nonlinear imaging

    SciTech Connect

    Tekavec, Patrick F.; Kozlov, Vladimir G. [Microtech Instruments, 858 West Park Street, Eugene, OR 97401 (United States)

    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 ?W 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.

  9. Reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.; Magnus, F.; Tryggvason, T. K.; Sveinsson, O. B.; Olafsson, S.

    2012-10-01

    Here we discuss reactive high power impulse magnetron sputtering sputtering (HiPIMS) [1] of Ti target in an Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on both the pulse repetition frequency and discharge voltage. The discharge current increases with decreasing frequency or voltage. This we attribute to an increase in the secondary electron emission yield during the self-sputtering phase of the pulse, as nitride [2] or oxide [3] forms on the target. We also discuss the growth of TiN films on SiO2 at temperatures of 22-600 ^oC. The HiPIMS process produces denser films at lower growth temperature and the surface is much smoother and have a significantly lower resistivity than dc magnetron sputtered films on SiO2 at all growth temperatures due to reduced grain boundary scattering [4].[4pt] [1] J. T. Gudmundsson, N. Brenning, D. Lundin and U. Helmersson, J. Vac. Sci. Technol. A, 30 030801 (2012)[0pt] [2] F. Magnus, O. B. Sveinsson, S. Olafsson and J. T. Gudmundsson, J. Appl. Phys., 110 083306 (2011)[0pt] [3] F. Magnus, T. K. Tryggvason, S. Olafsson and J. T. Gudmundsson, J. Vac. Sci. Technol., submitted 2012[0pt] [4] F. Magnus, A. S. Ingason, S. Olafsson and J. T. Gudmundsson, IEEE Elec. Dev. Lett., accepted 2012

  10. Improved Collectors for High Power Gyrotrons

    SciTech Connect

    R. Lawrence Ives, Amarjit Singh, Michael Read, Philipp Borchard, Jeff Neilson

    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.

  11. Coherently coupled high-power fiber arrays

    NASA Astrophysics Data System (ADS)

    Anderegg, Jesse; Brosnan, Stephen; Cheung, Eric; Epp, Paul; Hammons, Dennis; Komine, Hiroshi; Weber, Mark; Wickham, Michael

    2006-02-01

    A four-element fiber array has demonstrated 470 watts of coherently phased, linearly polarized light energy in a single far-field spot. Each element consists of a single-mode fiber-amplifier chain. Phase control of each element is achieved with a Lithium-Niobate phase modulator. A master laser provides a linearly polarized, narrow linewidth signal that is split into five channels. Four channels are individually amplified using polarization maintaining fiber power amplifiers. The fifth channel is used as a reference arm. It is frequency shifted and then combined interferometrically with a portion of each channel's signal. Detectors sense the heterodyne modulation signal, and an electronics circuit measures the relative phase for each channel. Compensating adjustments are then made to each channel's phase modulator. This effort represents the results of a multi-year effort to achieve high power from a single element fiber amplifier and to understand the important issues involved in coherently combining many individual elements to obtain sufficient optical power for directed energy weapons. Northrop Grumman Corporation and the High Energy Laser Joint Technology Office jointly sponsored this work.

  12. High power linear pulsed beam annealer

    DOEpatents

    Strathman, Michael D. (Concord, CA); Sadana, Devendra K. (Berkeley, CA); True, Richard B. (Sunnyvale, CA)

    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.

  13. Reliability of high-power QCW arrays

    NASA Astrophysics Data System (ADS)

    Feeler, Ryan; Junghans, Jeremy; Remley, Jennifer; Schnurbusch, Don; Stephens, Ed

    2010-02-01

    Northrop Grumman Cutting Edge Optronics has developed a family of arrays for high-power QCW operation. These arrays are built using CTE-matched heat sinks and hard solder in order to maximize the reliability of the devices. A summary of a recent life test is presented in order to quantify the reliability of QCW arrays and associated laser gain modules. A statistical analysis of the raw lifetime data is presented in order to quantify the data in such a way that is useful for laser system designers. The life tests demonstrate the high level of reliability of these arrays in a number of operating regimes. For single-bar arrays, a MTTF of 19.8 billion shots is predicted. For four-bar samples, a MTTF of 14.6 billion shots is predicted. In addition, data representing a large pump source is analyzed and shown to have an expected lifetime of 13.5 billion shots. This corresponds to an expected operational lifetime of greater than ten thousand hours at repetition rates less than 370 Hz.

  14. Brazing dissimilar aluminum alloys

    NASA Technical Reports Server (NTRS)

    Dalalian, H.

    1979-01-01

    Dip-brazing process joins aluminum castings to aluminum sheet made from different aluminum alloy. Process includes careful cleaning, surface preparation, and temperature control. It causes minimum distortion of parts.

  15. Breakdown phenomena in high power klystrons

    SciTech Connect

    Vlieks, A.E.; Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Hoyt, E.W.; Lebacqz, J.V.; Lee, T.G.

    1988-03-01

    In the course of developing new high peak power klystrons at SLAC, high electric fields in several regions of these devices have become an important source of vacuum breakdown phenomena. In addition, a renewed interest in breakdown phenomena for nanosecond pulse, multi-megavolt per centimeter fields has been sparked by recent R and D work in the area of gigawatt RF sources. The most important regions of electrical breakdown are in the output cavity gap area, the RF ceramic windows, and the gun ceramic insulator. The details of the observed breakdown in these regions, experiments performed to understand the phenomena and solutions found to alleviate the problems will be discussed. Recently experiments have been performed on a new prototype R and D klystron. Peak electric fields across the output cavity gaps of this klystron exceed 2 MV/cm. The effect of peak field duration (i.e. pulse width) on the onset of breakdown have been measured. The pulse widths varied from tens of nanoseconds to microseconds. Results from these experiments will be presented. The failure of ceramic RF windows due to multipactor and puncturing was an important problem to overcome in order that our high power klystrons would have a useful life expectancy. Consequently many studies and tests were made to understand and alleviate window breakdown phenomena. Some of the results in this area, especially the effects of surface coatings, window materials and processing techniques and their effects on breakdown will be discussed. Another important source of klystron failure in the recent past at SLAC has been the puncturing of the high voltage ceramic insulator in the gun region. A way of alleviating this problem has been found although the actual cause of the puncturing is not yet clear. The ''practical'' solution to this breakdown process will be described and a possible mechanism for the puncturing will be presented. 9 refs., 5 figs., 3 tabs.

  16. Aluminum extraction from aluminum industrial wastes

    NASA Astrophysics Data System (ADS)

    Amer, A. M.

    2010-05-01

    Aluminum dross tailings, an industrial waste from the Egyptian Aluminum Company (Egyptalum), was used to produce two types of alums: aluminum sulfate alum (Al2(SO4)3·12H2O) and ammonium aluminum alum {(NH4)2SO4AL2 (SO4)3·24H2O}. This was carried out in two processes. The first involves leaching the impurities using diluted H2SO4 with different solid/liquid ratios at different temperatures to dissolve the impurities present in the starting material in the form of aluminum sulfates. The second process is the extraction of aluminum (as aluminum sulfate) from the purified aluminum dross tailings thus produced. This was carried out in an autoclave. The effects of temperature, time of reaction, and acid concentration on pressure leaching and extraction processes were studied in order to specify the optimum conditions to be applied in the bench scale production as well as the kinetics of leaching process.

  17. Vibration characteristic of high power CO2 laser

    NASA Astrophysics Data System (ADS)

    Zhang, Kuo

    2015-02-01

    High power CO2 laser is widely used in various scientific, industrial and military applications. Vibration is a common phenomenon during laser working process, it will affect the working performance of high power CO2 laser, vibration must be strictly controlled in the condition where the laser pointing is required. This paper proposed a method to investigate the vibration characteristic of high power CO2 laser. An experiment device with vibration acceleration sensor was established to measure vibration signal of CO2 laser, the measured vibration signal was mathematically treated using space-frequency conversion, and then the vibration characteristic of high power CO2 laser can be obtained.

  18. High-power semiconductor separate-confinement double heterostructure lasers

    SciTech Connect

    Tarasov, I S [A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

    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)

  19. Advanced cathode material for high power applications.

    SciTech Connect

    Amine, K.; Belharouak, I.; Kang, S. H.; Liu, J.; Vissers, D.; Henriksen, G.; Chemical Engineering

    2005-01-01

    In our efforts to develop low cost high-power Li-ion batteries with excellent safety, as well as long cycle and calendar life, lithium manganese oxide spinel and layered lithium nickel cobalt manganese oxide cathode materials were investigated. Our studies with the graphite/LiPF{sub 6}/spinel cells indicated a very significant degradation of capacity with cycling at 55 C. This degradation was caused by the reduction of manganese ions on the graphite surface which resulted in a significant increase of the charge-transfer impedance at the anode/electrolyte interface. To improve the stability of the spinel, we investigated an alternative salt that would not generate HF acid that may attack the spinel. The alternative salt we selected for this work was lithium bisoxalatoborate, LiB(C{sub 2}O{sub 4}){sub 2} ('LiBoB'). In this case, the graphite/LiBoB/spinel Li-ion cells exhibited much improved cycle/calendar life at 55 C and better abuse tolerance, as well as excellent power. A second system based on LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} layered material was also investigated and its performance was compared to commercial LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}. Cells based on LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} showed lower power fade and better thermal safety than the LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}-based commercial cells under similar test conditions. Li-ion cells based on the material with excess lithium (Li{sub 1.1}Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2}) exhibited excellent power performance that exceeded the FreedomCAR requirements.

  20. 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

    A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz {approx} half cycle pulse whose average brightness is > 5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted[1]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [2]: up to 10 kW of average power in the IR from 1 to 14 microns in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 microseconds long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and discuss some of the discoveries we have made concerning the physics performance, design optimization, and operational limitations of such a first generation high power ERL light source.

  1. 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 ?m to >16 ?m 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 ?m - 5.0 ?m 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 ?m-10.0 ?m 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 ?m to >16 ?m, the QCLs have found instantaneous acceptance for insertion into multitude of defense and homeland security applications, including laser sources for infrared countermeasures for protecting aircraft from MANPADS, testing of infrared countermeasures, MWIR and LWIR lasers for identify-friend-or-foe (IFF) personnel beacons, infrared target illuminators and designators and tunable QCL applications including in-situ and standoff detection of chemical warfare agents (CWAs) and explosives. The last of these applications addresses a very important and timely need for detection of improvised explosive devices (IEDs) in combat environments like Iraq and Afghanistan.

  2. Fusion cutting of aluminum, magnesium, and titanium alloys using high-power fiber laser

    NASA Astrophysics Data System (ADS)

    Scintilla, Leonardo Daniele; Tricarico, Luigi

    2013-07-01

    The effects of cutting speed and assist gas pressure on laser cutting of 1-mm thick Al 1050, AZ31, and Ti6Al4V lightweight alloys are experimentally investigated. Fiber laser cutting of these materials is not broadly investigated and the acquisition of a new level of knowledge is of fundamental importance for applications like sheet metal trimming in automotive industry. The main process outputs are in depth compared with results reported in literature and obtained by cutting with CO2 and Nd?YAG lasers. The good cut quality, the high productivity, and the easy delivery of the beam obtained at the same time, corroborate the advantage of using fiber lasers for thin sheets lightweight alloys cutting.

  3. Effect of Rare-Earth and Aluminum Ions on the High-Power Threshold of YIG

    Microsoft Academic Search

    Russell G. West; Alvin C. Blankenship; Robert L. Huntt

    1971-01-01

    The 9.4 GHz parallel pump microwave threshold field (hcrit) has been measured at 293°K for polycrystalline YIG and YA1IG spherical samples containing Ho3+, Dy3+, Ce3+, and Gd3+ singly or in combination. Low wave number spin-wave linewidths (?Hk?0) were determined by adjusting the dc magnetic field to obtain a threshold field corresponding to the butterfly minimum. The experimental results justify a

  4. From the electromagnetic pulse to high-power electromagnetics

    NASA Astrophysics Data System (ADS)

    Baum, Carl E.

    1992-06-01

    This paper updates the published literature of the late 1970's concerning the development of requisite technology for the nuclear EMP. EMP has impacted a set of related areas that can be collectively referred to as high-power electromagnetics. This includes high-power microwaves, direct-strike lightning, and some aspects of transient radar.

  5. Wavelength stabilized high-power diode laser modules

    Microsoft Academic Search

    Bernd Köhler; Thomas Brand; Matthias Haag; Jens Biesenbach

    2009-01-01

    In this work we report on high-power diode laser modules with enhanced spectral brightness by means of volume holographic gratings for wavelength stabilization. High-power diode laser modules typically have a relatively broad spectral width of about 3 to 6 nm. In addition the center wavelength shifts by changing the temperature and the driving current, which is obstructive for pumping applications

  6. Water Cooling of High Power Light Emitting Diode Henrik Srensen

    E-print Network

    Berning, Torsten

    Water Cooling of High Power Light Emitting Diode Henrik Sørensen Department of Energy Technology and product lifetime. The high power Light Emitting Diodes (LED) belongs to the group of electronics 1411 Email: hs@et.aau.dk ABSTRACT The development in light technologies for entertainment is moving

  7. 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.

  8. High-Power Microwave Breakdown of Dielectric Interfaces

    Microsoft Academic Search

    Steve Eugene Calico

    1991-01-01

    A project to study the electrical breakdown of microwave windows due to high-power pulsed microwave fields was undertaken at Texas Tech University. The pulsed power equipment was acquired from the Air Force Weapons Laboratory in Albuquerque, NM, refurbished and redesigned as necessary, and serves as the high-power microwave source. The microwaves are used to test various vacuum to atmosphere interfaces

  9. Development of High Power Lasers for Materials Interactions

    Microsoft Academic Search

    Hackel

    2003-01-01

    The Lawrence Livermore National Laboratory (LLNL) has a long history of developing high power lasers for use in basic science and applications. The Laser Science and Technology Program (LS&T) at LLNL supports advanced lasers and optics development both for the National Ignition Facility (NIF) as well as for high power lasers and optics technology for a broader range of government,

  10. Status of Z-Pinch Research Fusion Power Associates

    E-print Network

    More current than on Z will enable up to: 50% increase ­ x-ray power radiated 70% increase ­ x 20 Torr Inert Gas Inert Gas Flow for Contamination Control Cartridge Large Particulate Collections First System Test ­ New Z #12;8 Z-shot #1775 achieved a load current of 26.4 MA The measured load

  11. Z-Pinch Inertial Fusion Energy Fusion Power Associates Annual

    E-print Network

    (g/cc) -Yo(GPa) Sesame 3520 Sesame 3521 LANL 90210 0 50 100 150 200 250 300 350 400 16.5 19.5 22.5 25.5 28.5 31.5 Density (g/cc) -Yo(GPa) The extracted isentrope discriminates between various tabular equations of state for Ta 0 50 100 150 200 250 300 350 400 16.5 19.5 22.5 25.5 28.5 31.5 Density (g/cc) -Yo

  12. DEVELOPMENT AND TESTING OF HIGH POWER RF VECTOR MODULATORS*

    SciTech Connect

    Kang, Yoon W [ORNL; Wilson, Joshua L [ORNL; Champion, Mark [FNAL; Hardek, Thomas W [ORNL; Kim, Sang-Ho [ORNL; McCarthy, Mike [ORNL; Vassioutchenko, Alexandre V [ORNL

    2007-01-01

    A fan-out RF power distribution system can allow many accelerating cavities to be powered by a single high-power klystron amplifier. High-power vector modulators can perform independent control of amplitudes and phases of RF voltages at the cavities without changing the klystron signal. A prototype highpower RF vector modulator employing a quadrature hybrid and two ferrite phase shifters in coaxial TEM transmission lines has been built and tested for 402.5 MHz. RF properties of the design and results of high power testing are presented.

  13. 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.

  14. Duty cycle and modulation effects in aluminium alloy welding with high power Nd-YAG laser

    SciTech Connect

    Kathuria, Y.P.; Tsuboi, Akihiko [Laser X Co. Ltd., Chiryu, Aichi (Japan)

    1996-12-31

    The demand for the light aluminum vehicles using aluminium alloys will be strengthened in the future. The development of aluminium alloys, e.g., Al-Mg and Al-Zn-Mg alloys is being actively considered and have resulted good results. In view of this, processing of Al-alloys, specially its weldability has been of much importance. Here, the modulation and duty cycle effects on Al-alloy welding with high power Nd-YAG laser are investigated. Microstructural characterization of the low and high duty welds with wave modulation identified the differences in the weld morphology. Welding depth, undercut and strength of fusion zone are discussed as a function of the processing parameters.

  15. Study of colliding dense foils accelerated by high-power laser radiation

    SciTech Connect

    Bolotin, V.A.; Velikovich, A.L.; Gavrilov, V.V.; Gold`berg, S.M.; Gol`tsov, A.Yu.; Zavyalets, S.V.; Koval`skii, N.G.; Kondrashov, V.N.

    1993-04-01

    Results are presented from experimental investigations of collisions between dense aluminum and mylar foils of micron thickness accelerated by high-power laser radiation [{lambda} = 1.054 {mu}m, I = (5-7)]{center_dot}10{sup 13} W/cm{sup 2}, pulse length 2 ns. The {open_quotes}method of induced opacity{close_quotes} developed in the present work allows the density of the accelerated plasma foil to be estimated when it strikes a fixed obstacle. The experimental data and the results of numerical simulations show that a {open_quotes}soft{close_quotes} acceleration regime can occur in a two-stage scheme, in which a thin-film target is accelerated by the action of a plasmoid incident on it to several tens of kilometers per second while maintaining its condensed state. 28 refs., 11 figs., 1 tab.

  16. Investigation on the aging characteristics of high-power white LEDs under different stresses

    NASA Astrophysics Data System (ADS)

    Yan, Jing; Shang, Zhendong; Chen, Jianxin

    2009-11-01

    We used two types of 1-W white LEDs, both of which had the structure of GaN chip with phosphor covered and packaged in metal PCB boards with laminated aluminum. Of the two types of packaging lens, one is made of hard silica gel, and the other is made of soft plastic. The purpose of this paper is to analyze the aging characters of high-power white LEDs under stresses. In accelerated life tests, the two types of white LEDs were treated with high temperature and DC current distinctively. The tendencies of the decay of luminous flux in the two conditions were basically the same, while the changing trends of the color temperature were different. The hard silica gel had better stability.

  17. Innovative fuel designs for high power density pressurized water reactor

    E-print Network

    Feng, Dandong, Ph. D. Massachusetts Institute of Technology

    2006-01-01

    One of the ways to lower the cost of nuclear energy is to increase the power density of the reactor core. Features of fuel design that enhance the potential for high power density are derived based on characteristics of ...

  18. Design of annular fuel for high power density BWRs

    E-print Network

    Morra, Paolo

    2005-01-01

    Enabling high power density in the core of Boiling Water Reactors (BWRs) is economically profitable for existing or new reactors. In this work, we examine the potential for increasing the power density in BWR plants by ...

  19. 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

  20. 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

  1. Arc-Free High-Power dc Switch

    NASA Technical Reports Server (NTRS)

    Miller, W. N.; Gray, O. E.

    1982-01-01

    Hybrid switch allows high-power direct current to be turned on and off without arcing or erosion. Switch consists of bank of transistors in parallel with mechanical contacts. Transistor bank makes and breaks switched circuit; contacts carry current only during steady-state "on" condition. Designed for Space Shuttle orbiter, hybrid switch can be used also in high-power control circuits in aircraft, electric autos, industrial furnaces, and solar-cell arrays.

  2. Analysis of geometric variations in high-power tokamak divertors

    Microsoft Academic Search

    M. V. Umansky; R. H. Bulmer; R. H. Cohen; T. D. Rognlien; D. D. Ryutov

    2009-01-01

    Quantitative assessment of the performance of high-power tokamak divertors for a range of geometric variations is conducted using the MHD code Corsica (Crotinger et al 1997 Technical Report LLNL) and edge transport code UEDGE (Rognlien et al 1992 J. Nucl. Mater. 196-198 347). In a multi-parametric study the divertor performance is compared for a high-power tokamak with standard and snowflake

  3. In-situ strain observation in high power laser cladding

    Microsoft Academic Search

    V. Ocelík; J. Bosgra; J. Th. M. de Hosson

    2009-01-01

    The modern experimental technique – so called Digital Image Correlation – is applied during high power laser surface treatments for in-situ observation of displacements and strains near the processing area during and a short time after laser processing. An experimental setup has been designed and tested to measure in-situ the strain during treatment with a high power 2 kW CW Nd:YAG

  4. DOE HIGH-POWER SLIM-HOLE DRILLING SYSTEM

    Microsoft Academic Search

    William C. Maurer; John H. Cohen; J. Chris Hetmaniak; Curtis Leitko

    1999-01-01

    This project used a systems approach to improve slim-hole drilling performance. A high power mud motor, having a double-length power section, and hybrid PDC\\/TSP drill bit were developed to deliver maximum horsepower to the rock while providing a long life down hole. This high-power slim-hole drilling system drills much faster than conventional slim-hole motor and bit combinations and holds significant

  5. High power lasers on InP substrates

    Microsoft Academic Search

    Pierre Doussiere

    2011-01-01

    High power semiconductor lasers have found numerous applications in a wide variety of fields that include telecommunications, solid-state laser pumping, fiber laser pumping, direct laser, laser printing, and more recently in medical and cosmetic applications such as hair removal and skin treatment. So far, high power semiconductor lasers have been mainly designed with the AlGaAs\\/GaAs system since most of the

  6. A new high-power klystron for the DSN

    NASA Technical Reports Server (NTRS)

    Goldfinger, A.; Gregg, M. A.; Hartop, R.

    1982-01-01

    A very high reliability 100 kW klystron for the Deep Space Network (DSN) high power transmitters in support of spacecrafts to the distant planets was studied. The last phases included electron gun fabrication and beam analyzer evaluation and klystron prototype fabrication, mechanical and electrical design improvements resulted in the delivery of a prototype klystron meeting all requirements. It is concluded that the development of a new high power klystron for the DSN was very successful as demonstrated by the prototype results.

  7. Analysis of delamination and darkening in high power LED packaging

    Microsoft Academic Search

    Longzao Zhou; Bing An; Yiping Wu; Shunhong Liul

    2009-01-01

    Luminous emittance declination due to interfacial delamination and darkening is a fatal defect for the GaN-based high power light-emitting diodes (LEDs) under a long time service. This letter brought forward an accelerated aging test under 350 mA forward current, 25degC, 54% RH, 256 hours to testify and analysis the abnormal dark stain on the die surface of high power blue

  8. Heavy-section welding with very high power laser beams: the challenge

    NASA Astrophysics Data System (ADS)

    Goussain, Jean-Claude; Becker, Ahim; Chehaibou, A.; Leca, P.

    1997-08-01

    The 45 kW CO2 laser system of Institut de Soudure was used to evaluate and explore the possibilities offered by the high power laser beams for welding different materials in various thickness and in different welding positions. Stainless steels, low carbon steels, aluminum and titanium alloys were studied. Butt joints in 10 to 35 mm thick plates were achieved and evaluated by radiographic, metallurgical and mechanical tests. Gaps and alignment tolerances were determined with and without filler wire in order to obtain acceptable welds concerning the weld geometry, the aspect on front and end root sides. The main problem raised by heavy section welding concerns weld porosity in the weld which increases drastically with the thickness of the weld. Indications are given on their origin and the way to proceed in order to better control them. Lastly some large parts, recently welded on the system, are presented and discussed before drawing some conclusions on the prospects of very high power laser welding.

  9. 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.

  10. Corrosion of aluminum and aluminum alloys

    SciTech Connect

    Davis, J.R. (ed.)

    1999-01-01

    This new handbook presents comprehensive coverage of the corrosion behavior of aluminum and aluminum alloys, with emphasis on practical information about how to select and process these materials in order to prevent corrosion attack. Described are the characteristics of these materials and the influences of composition, mechanical working, heat treatment, joining methods, microstructure, and environmental variables on their corrosion.

  11. Aluminum hydroxide production

    SciTech Connect

    Martin, E.S.; Weaver, M.L.

    1988-07-05

    A method is described for the production of aluminum hydroxide, comprising reacting water in the liquid phase and aluminum of surface area of at least 20 mm/sup 2/ per gram at a pH above about 12.4 for producing a reaction mixture containing aluminum hydroxide, and collecting solid aluminum hydroxide from the reaction mixture, the reaction being carried out in the presence of choline at a concentration of about 0.05 to 2 mols per liter.

  12. Combining new, high-power packages with high-power ICs answers need for hermetic, military motor control electronics

    Microsoft Academic Search

    P. R. Emerald

    1989-01-01

    Two high-power hermetic packages have been tooled that offer the combination of increased lead-count and thermal ratings needed to provide military-grade power ICs. This work concerns the two package styles, and the initial high-power motor ICs that utilize them. The first is a 15-lead TO-204 style (formerly called the TO-3), that uses conventional materials, form factor, and manufacturing techniques. The

  13. A three-phase soft-switched high-power-density DC\\/DC converter for high-power applications

    Microsoft Academic Search

    Rik W. A. A. De Doncker; Deepakraj M. Divan; Mustansir H. Kheraluwala

    1991-01-01

    Three DC\\/DC converter topologies suitable for high-power-density high-power applications are presented. All three circuits operate in a soft-switched manner, making possible a reduction in device switching losses and an increase in switching frequency. The three-phase dual-bridge converter proposed is shown to have the most favorable characteristics. This converter consists of two three-phase inverter stages operating in a high-frequency six-step mode.

  14. A three-phase soft-switched high power density DC\\/DC converter for high power applications

    Microsoft Academic Search

    R. W. De Doncker; D. M. Divan; M. H. Kheraluwala

    1988-01-01

    The authors present three DC\\/DC converter topologies suitable for high-power-density high-power applications. All three circuits operate in a soft-switched manner, making possible a reduction in device switching losses and an increase in switching frequency. The three-phase dual-bridge converter proposed is seen to have the most favorable characteristics. This converter consists of two three-phase inverter stages operating in a high frequency

  15. 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)

  16. 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.

  17. 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.

  18. High-power lead-acid batteries for different applications

    NASA Astrophysics Data System (ADS)

    Wagner, Rainer

    High-power lead-acid batteries have been used for a rather long time in various applications, especially for uninterruptible power supplies (UPSs) and starting of automobiles. Future automotive service requires, in addition to cold-cranking performance, the combination of high-power capability, a very good charge-acceptance, and an excellent cycle-life. Such applications include stop-start, regenerative braking, and soft, mild and full hybrid vehicles. For UPS, there has been a clear tendency to shorter discharge times and higher discharge rates. During the past decades, the specific power of lead-acid batteries has been raised steadily and there is still, room for further improvement. This paper gives an overview of the progress made in the development of high-power lead-acid batteries and focuses on stationary and automotive applications.

  19. Industrial applications of high power diode lasers in materials processing

    NASA Astrophysics Data System (ADS)

    Bachmann, Friedrich

    2003-03-01

    Diode lasers are widely used in communication, computer and consumer electronics technology. These applications are based on systems, which provide power in the milliwatt range. However, in the mean time high power diode lasers have reached the kilowatt power range. This became possible by special cooling and mounting as well as beam combination and beam forming technologies. Such units are nowadays used as a direct source for materials processing. High power diode lasers have entered the industrial manufacturing area [Proceedings of the Advanced Laser Technologies Conference 2001, Proc. SPIE, Constanta, Romania, 11-14 September 2001].

  20. Ultra high vacuum broad band high power microwave window

    DOEpatents

    Nguyen-Tuong, Viet (Seaford, VA); Dylla, III, Henry Frederick (Yorktown, VA)

    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.

  1. High power ytterbium-doped fiber lasers — fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Zervas, Michalis N.

    2014-03-01

    In this paper, we summarize the fundamental properties and review the latest developments in high power ytterbium-doped fiber (YDF) lasers. The review is focused primarily on the main fiber laser configurations and the related cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancements observed in high power fiber lasers. The review also includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, modal instabilities and photodarkening. The paper summarizes the power evolution in continuous-wave (CW) and pulsed YDF lasers and their impact on material processing and other industrial applications.

  2. High power density direct formic acid fuel cells

    NASA Astrophysics Data System (ADS)

    Zhu, Yimin; Ha, Su Y.; Masel, Richard I.

    A demonstration of direct formic acid fuel cells (DFAFCs) generating relatively high power density at ambient temperature is reported. The performance of Nafion 112-based DFAFCs with different concentrations of formic acid at different temperatures has been evaluated. DFAFCs operated with dry air and zero back-pressure can generate power densities of 110 and 84 mW cm -2 at 30 and 18 °C, respectively, which are considerably higher than direct methanol fuel cells (DMFCs) operated under the same conditions. The DFAFCs are especially suited to power portable devices used at ambient temperature because the significant high power density can be achieved with highly concentrated formic acid.

  3. Thrust stand for high-power electric propulsion devices

    NASA Technical Reports Server (NTRS)

    Haag, T. W.

    1991-01-01

    This paper describes a new high-power thrust stand developed for use with high-power (up to 250 kW) magnetoplasmadynamic (MPD) thrusters, which is installed in a high-vacuum MPD facility at Lewis Research Center. The design of the stand is based on inverted pendulum configuration, with the result of large displacements and high resolution. Calibration results showed that thrust measurements were linear and repeatable to within a fraction of 1 percent. The thrust stand was used for testing water-cooled MPD thrusters at power levels up to 125 kW. The thruster, however, is quite well suited for testing other types of electric propulsion devices.

  4. 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.

  5. Application of high-Tc superconductors in aluminum electrolysis plants

    Microsoft Academic Search

    Magne Runde

    1995-01-01

    The electric power system in an aluminum electrolysis plant has several features that may advocate use of superconducting technology: high power, low voltage, system compactness, direct current, and substantial conductor cost and losses per meter. Two case studies where the cost of conventional busbar conductors is compared with the predicted cost of a future nitrogen-cooled high-amperage superconductor based on Ag\\/BSCCO

  6. Aluminum: Recycling of Aluminum Dross\\/Saltcake

    Microsoft Academic Search

    Blazek

    1999-01-01

    As this NICE3 publication details, the objective of this project is to commercialize the process technology to eliminate all landfill waste associated with black dross and saltcake generated from aluminum recycling in the United States.

  7. High power light emitting diode based setup for photobleaching fluorescent impurities

    E-print Network

    Kaufman, Laura

    High power light emitting diode based setup for photobleaching fluorescent impurities Tobias K be photobleached before final sample preparation. The instrument consists of high power light emitting diodes

  8. High power density, high frequency, and high voltage pulse transformer

    Microsoft Academic Search

    S. C. Kim; S. H. Nam; D. T. Kim

    2001-01-01

    Summary form only given, as follows. In designing a compact and high efficiency TWT microwave amplifier, the role of a high power density DC power supply is very important. In order to reduce volume of the power supply, it is necessary to increase switching frequency of the power supply. The high operation frequency mainly reduces transformer volume in the power

  9. High power density, high frequency, and high voltage pulse transformer

    Microsoft Academic Search

    S. C. Kim; S. H. Nam; S. H. Kim; D. T. Kim; S. H. Jeong

    2001-01-01

    In designing a compact and high efficiency TWT microwave amplifier, the role of a high power density DC power supply is very important. In order to reduce volume of the power supply, it is necessary to increase switching frequency of the power supply. The high operation frequency mainly reduces transformer volume in the power supply. However, a step-up ratio of

  10. Baseline conceptual design for high-power FEL ring cavities

    Microsoft Academic Search

    J. M. Eggleston; J. M. Slater

    1987-01-01

    A baseline conceptual design of a semi-confocal ring resonator for high-power free-electron lasers is presented. An algorithm is developed for identifying the minimum cavity length and element sizes for a given power level. Equations for the exact mirror surfaces are presented and a simple implementation of a single smart mirror stabilization system is proposed.

  11. Baseline conceptual design for high-power FEL ring cavities

    NASA Astrophysics Data System (ADS)

    Eggelston, John M.; Slater, Jack M.

    1987-09-01

    A baseline conceptual design of a semi-confocal ring resonator for high-power free-electron lasers is presented. An algorithm is developed for identifying the minimum cavity length and element sizes for a given power level. Equations for the exact mirror surfaces are presented and a simple implementation of a single smart mirror stabilization system is proposed.

  12. Pulsed power-driven high-power microwave sources

    Microsoft Academic Search

    SERGEI D. KOROVIN; VLADISLAV V. ROSTOV; SERGEI D. POLEVIN; IGOR V. PEGEL; EDL SCHAMILOGLU; MIKHAIL I. FUKS; ROBERT J. BARKER

    2004-01-01

    The advent of pulsed power technology in the 1960s has enabled the development of very high peak power sources of electromagnetic radiation in the microwave and millimeter wave bands of the electromagnetic spectrum. Such sources have applications in plasma physics, particle acceleration techniques, fusion energy research, high-power radars, and communications, to name just a few. This article describes recent ongoing

  13. HPW (High Power Microwave) testing of electronic components

    Microsoft Academic Search

    R. Antinone; W. C. Ng

    1989-01-01

    This report documents the results of a study of high power microwave (HPM) vulnerability of electronic components commonly used in weapon systems. The study was carried out at the Lawrence Livermore National Laboratory from August through October 1988. The objective of this study was to determine the threshold levels for upset or disturbance and damage of the devices under test

  14. High power DC-to-DC converter for supercapacitors

    Microsoft Academic Search

    B. J. Arnet; L. P. Haines

    2001-01-01

    The purpose of this paper is to present Solectria's approach to the design and realization of a high power, nonisolated DC-to-DC power converter for supercapacitors. The study focuses on supercapacitor specific design rules and on how to integrate the unit into a system with other energy storage devices and converters. Two applications are presented to illustrate the validity of the

  15. Diode pumped alkali vapor lasers for high power applications

    Microsoft Academic Search

    J. Zweiback; B. Krupke; A. Komashko

    2008-01-01

    General Atomics has been engaged in the development of diode pumped alkali vapor lasers. We have been examining the design space looking for designs that are both efficient and easily scalable to high powers. Computationally, we have looked at the effect of pump bandwidth on laser performance. We have also looked at different lasing species. We have used an alexandrite

  16. Busbar design considerations for high power IGBT converters

    Microsoft Academic Search

    H. J. Beukes; J. H. R. Enslin; R. Spee

    1997-01-01

    This paper addresses an important issue in the design and synthesis of high power IGBT converters, i.e. the layout and design of connection busbars. Parasitic inductance, caused by the physical distance current has to flow from the storage capacitors to the static switches and back, is the major constraint in developing a bus structure. This leads to nonideal converter operation,

  17. Delay time distribution of high power microwave surface flashover

    Microsoft Academic Search

    J. Foster; H. Krompholz; A. Neuber

    2011-01-01

    Breakdown phenomena in a high power microwave (HPM) system present unique obstacles for the further development of HPM technology. The non-uniformity of a high frequency electric field and the statistics associated with breakdown in general along with the stochastic nature of naturally occurring electron generating mechanisms introduce significant challenges for predicting and preventing breakdown occurrences within a HPM system. An

  18. Modeling of copper wire bonding process on high power LEDs

    Microsoft Academic Search

    Zhaohui Chen; Yong Liu; Sheng Liu

    2011-01-01

    In this paper, a couple thermal mechanical transient dynamic finite element framework of copper wire bonding process on high power lighting emitting diodes (LEDs) is developed, which considers the thermal heating effects of friction and plastic deformation. The whole wire bonding process is simplified to consist of impact and ultrasonic vibration stages. Parametric studies are also carried out to examine

  19. High dielectric constant composites for high power antennas

    Microsoft Academic Search

    K. A. O'Connor; R. D. Curry

    2011-01-01

    The volume and weight of high power antennas can be a limiting factor for compact pulsed power transmitters. Options for antenna minimization are limited due to the relationship between an antenna's physical dimensions and the frequencies which can be transmitted. Thus, low frequency antennas often require dimensions on the order of meters. An effort undertaken at the University of Missouri

  20. Hybrid High Power Amplifiers for L-Band Space Application

    Microsoft Academic Search

    Corrado Florian; Francesco Scappaviva; R. P. Paganelli; I. Melczarsky; R. Cignani; M. Pirazzini; R. Giordani; M. Feudale; G. Vannini; F. Filicori

    2007-01-01

    This paper describes the design and implementation of 2 hybrid high power amplifiers at L band for a space application. Indeed, the amplifiers represent prototype test vehicles for a larger hybrid amplifier to be used as the final power stage in the transmitting chain of a T\\/R module of an L-band SAR antenna for earth observation. The amplifiers described in

  1. HF high power electronically tunable helical resonator filter

    Microsoft Academic Search

    R.-F. Xue; B. Yuan; J. Mao; C.-H. Liang

    2006-01-01

    A novel design of a high power electronically tunable helical resonator filter suitable for applications in HF radio communication is proposed. The helical resonator is loaded in the middle of the helix and the tuning element is set outside the cavity. Theoretical analysis and experimental verification are demonstrated.

  2. Lithium Mass Flow Control for High Power Lorentz Force Accelerators

    E-print Network

    Choueiri, Edgar

    ´es, Ecole Polytechnique, F-91128 Palaiseau Cedex FRANCE 3 Advanced Propulsion Group, Jet Propulsion Emsellem1,2 , Leonard D. Cassady1 , James E. Polk3 , Edgar Y. Choueiri1 1 Electric Propulsion and Plasma Accelerator (LiLFA) is a high power electric propulsion option currently being considered by NASA for heavy

  3. Transmutation and energy production with high power accelerators

    SciTech Connect

    Lawrence, G. P.

    1996-01-01

    Accelerator-driven transmutation offers attractive new solutions to complex nuclear problems. This paper outlines the basics of the technology, summarizes the key application areas, and discusses designs of and performance issues for the high-power proton accelerators that are required.

  4. Transmutation and energy-production with high power accelerators

    SciTech Connect

    Lawrence, G.P.

    1995-07-01

    Accelerator-driven transmutation offers attractive new solutions to complex nuclear problems. This paper outlines the basics of the technology, summarizes the key application areas, and discusses designs of and performance issues for the high-power proton accelerators that are required.

  5. High power, high resolution terahertz spectroscopy technologies and its applications

    NASA Astrophysics Data System (ADS)

    Wu, Dong Ho; Graber, Benjamin; Kim, Christopher

    2015-03-01

    Since a large number of molecules' resonance frequencies lie within terahertz frequencies, terahertz spectroscopy is a highly useful tool for scientific investigation of various materials. At the same time one can use the same technology for the identification of hidden materials. Despite these potential applications presently terahertz spectroscopy is largely underutilized, and it is mostly being used in the laboratory environment. This is in part largely due to the fact that no portable, high power, high resolution spectrometer is currently available. So we have been developing a high power, wideband terahertz source. The terahertz source is capable to produce a relatively high power (>2 mW), wideband (0.1 - 3 THz) terahertz beam. In addition to the source we have optimized and calibrated an electro-optic (EO) detector, of which sensitivity is 10-13 W/(Hz)1/2. Recently, by utilizing these terahertz source and detector, we have constructed a high power, high resolution terahertz spectrometer, and carried out various experiments to understand resonance spectra of water vapor, chemicals and ionized air. Also we constructed a modified terahertz spectrometer for a stand-off detection applications. In this presentation I will discuss our experimental achievements and progresses. Supported by DTRA.

  6. 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.

  7. High power microwave technology and its military implications

    Microsoft Academic Search

    N. S. Kushwaha; M. M. Sharma

    2008-01-01

    In this paper, electromagnetic bomb is discussed with main emphasis on maximizing the lethality of the bomb by suitably designing the antenna, which can couple the high power microwaves to the targets, efficiently. Some other methods for maximizing the lethality are also discussed.

  8. Aspects of aluminum toxicity

    SciTech Connect

    Hewitt, C.D.; Savory, J.; Wills, M.R. (Univ. of Virginia Health Sciences Center, Charlottesville (USA))

    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.

  9. Aluminum powder metallurgy processing

    SciTech Connect

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  10. Aluminum in automobiles

    SciTech Connect

    Kasper, A.S.

    1983-11-01

    Automotive materials conversion to aluminum is increasing from 35 kgs in the 70's to more than 60 kgs average in the 1983 U.S. vehicles. To control mass, aluminum intensive vehicles with 180 kgs of aluminum are already in production for greater luxury, roominess, performance, and fuel efficiency. Optimization of aluminum designs and processing is achieved through the total design concept of ''Putting It All Together''. A total of 225 kgs improves performance and maximizes the benefits for upsized vehicles by using current production components, drive trains, power plants, and press plant equipment.

  11. 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

    ...3-Advanced High Power Rockets— (a) At any altitude where clouds or obscuring phenomena of more than five-tenths coverage prevails...horizontal visibility is less than five miles; (c) Into any cloud; (d) Between sunset and sunrise without prior...

  12. 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

    ...3-Advanced High Power Rockets— (a) At any altitude where clouds or obscuring phenomena of more than five-tenths coverage prevails...horizontal visibility is less than five miles; (c) Into any cloud; (d) Between sunset and sunrise without prior...

  13. 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

    ...3-Advanced High Power Rockets— (a) At any altitude where clouds or obscuring phenomena of more than five-tenths coverage prevails...horizontal visibility is less than five miles; (c) Into any cloud; (d) Between sunset and sunrise without prior...

  14. 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

    ...3-Advanced High Power Rockets— (a) At any altitude where clouds or obscuring phenomena of more than five-tenths coverage prevails...horizontal visibility is less than five miles; (c) Into any cloud; (d) Between sunset and sunrise without prior...

  15. 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

    ...3-Advanced High Power Rockets— (a) At any altitude where clouds or obscuring phenomena of more than five-tenths coverage prevails...horizontal visibility is less than five miles; (c) Into any cloud; (d) Between sunset and sunrise without prior...

  16. High-Power Density Design of a Soft-Switching High-Power Bidirectional dc–dc Converter

    Microsoft Academic Search

    Junhong Zhang; Jih-Sheng Lai; Rae-Young Kim; Wensong Yu

    2007-01-01

    A bidirectional dc-dc converter typically consists of a buck and a boost converters. In order to have high-power density, the converter can be designed to operate in discontinuous conducting mode (DCM) such that the passive inductor can be minimized. The DCM operation associated current ripple can be alleviated by interleaving multiphase currents. However, DCM operation tends to increase turnoff loss

  17. Carbothermic Aluminum Production Using Scrap Aluminum As A Coolant

    DOEpatents

    LaCamera, Alfred F. (Trafford, PA)

    2002-11-05

    A process for producing aluminum metal by carbothermic reduction of alumina ore. Alumina ore is heated in the presence of carbon at an elevated temperature to produce an aluminum metal body contaminated with about 10-30% by wt. aluminum carbide. Aluminum metal or aluminum alloy scrap then is added to bring the temperature to about 900-1000.degree. C. and precipitate out aluminum carbide. The precipitated aluminum carbide is filtered, decanted, or fluxed with salt to form a molten body having reduced aluminum carbide content.

  18. COMPACT POWER CONDITIONING AND RF SYSTEMS FOR A HIGH POWER RF SOURCE

    Microsoft Academic Search

    K. A. O'Connor; L. Altgilbers

    High power RF systems have increasing potential for application by the Army. High power RF, or high power microwave (HPM), systems can disrupt or disable enemy communications and weapons systems. Fundamental constraints on the availability of HPM sources to the war fighter are the size and portability. Traditional pulsed power systems capable of producing high power RF signals are massive

  19. IMPORTANCE OF THE DEVELOPMENT OF HIGH POWER DENSITY BOILING WATER REACTORS IN OBTAINING CHEAP NUCLEAR ENERGY

    Microsoft Academic Search

    D. H. Imhoff; S. Levy

    1962-01-01

    The importance of the development of high-power density boiling water ; reactors is evaluated. The objectives, economic advantages, and actual situation ; in the development are examined. The reason for the high power density, economic ; factors in high power densities, the present situation in the development of high ; power densities, and the importance of continued study in this

  20. Anodizing Aluminum with Frills.

    ERIC Educational Resources Information Center

    Doeltz, Anne E.; And Others

    1983-01-01

    "Anodizing Aluminum" (previously reported in this journal) describes a vivid/relevant laboratory experience for general chemistry students explaining the anodizing of aluminum in sulfuric acid and constrasting it to electroplating. Additions to this procedure and the experiment in which they are used are discussed. Reactions involved are also…

  1. Correlating Aluminum Burning Times

    Microsoft Academic Search

    M. W. Beckstead

    2005-01-01

    Characteristics of aluminum combustion are summarized in an overview of the subject, focusing on the burning time of individual particles. Combustion data from over ten different sources with almost 400 datum points have been cataloged and correlated. Available models have also been used to evaluate combustion trends with key environmental parameters. The fundamental concepts that control aluminum combustion are discussed,

  2. Technology requirements for high-power Lithium Lorentz Force accelerators

    SciTech Connect

    Polk, J.; Frisbee, R.; Krauthamer, S. [Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena, California91109 (United States); Tikhonov, V.; Semenikhin, S.; Kim, V. [Research Institute of Applied Mechanics and Electrodynamics Moscow Aviation Institute 4 Volokolamskoe shosse Moscow, 125810 (Russia)

    1997-01-01

    Lithium Lorentz Force Accelerators (LFA{close_quote}s) are capable of processing very high power levels and are therefore applicable to a wide range of challenging missions. An analysis of a reusable orbit transfer vehicle with a solar or nuclear electric power source was performed to assess the applicability of high-power LFA{close_quote}s to this mission and to define engine performance and lifetime goals to help guide the technology development program. For this class of missions, the emphasis must be on achieving high efficiency at an Isp of 4000{endash}5000 s at power levels of 200{endash}250 kWe. The engines must demonstrate very reliable operation for a service life of about 3000 hours. These goals appear to be achievable with engine technologies currently under development. {copyright} {ital 1997 American Institute of Physics.}

  3. High power repetitive TEA CO2 pulsed laser

    NASA Astrophysics Data System (ADS)

    Yang, Guilong; Li, Dianjun; Xie, Jijiang; Zhang, Laiming; Chen, Fei; Guo, Jin; Guo, Lihong

    2012-07-01

    A high power repetitive spark-pin UV-preionized TEA CO2 laser system is presented. The discharge for generating laser pulses is controlled by a rotary spark switch and a high voltage pulsed trigger. Uniform glow discharge between two symmetrical Chang-electrodes is realized by using an auto-inversion circuit. A couple of high power axial-flow fans with the maximum wind speed of 80 m/s are used for gas exchange between the electrodes. At a repetitive operation, the maximum average output laser power of 10.4 kW 10.6 ?m laser is obtained at 300 Hz, with an electro-optical conversion efficiency of 15.6%. At single pulsed operation, more pumping energy and higher gases pressures can be injected, and the maximum output laser energy of 53 J is achieved.

  4. 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.

  5. TE_01 High Power Disk Loaded Guide Load

    SciTech Connect

    Farkas, Z.D.; /SLAC

    2005-06-01

    A method to design a matching section from a smooth guide to a disk-loaded guide, using a variation of broadband matching, [1, 2] is described. Using this method, we show how to design high power loads, attenuators and filters. The load consists of a disk-loaded coaxial guide operating in the TE{sub 01}-mode. We use this mode because it has no electric field terminating on a conductor, has no axial currents, and has no current at the cylinder-disk interface. A high power load design that has -35 dB reflection and a 200 MHz, -20 dB bandwidth, is presented. It is expected that it will carry the 600 MW output peak power of the pulse compression network. We use coaxial geometry and stainless steel material to increase the attenuation per cell.

  6. Annular resonators for high-power chemical lasers

    NASA Astrophysics Data System (ADS)

    Wade, Richard C.

    1993-08-01

    Resonators capable of extracting highly coherent energy from DF and HF chemical laser annular gain media have been under investigation for weapon application since 1974. This survey article traces the background of interest in these devices, describes the various concepts that have been experimentally and analytically investigated, and discusses the issues associated with their operation. From the discussion of issues, preferred concepts are selected. Applicability of these concepts to high-power operation is addressed through discussions of past and ongoing high-power demonstration programs and the issues facing their application to weapon sized devices capable of strategic and tactical missions such as ballistic missile defense (BMD), theater missile defense (TMD), and anti satellite (ASAT).

  7. Designing high power targets with computational fluid dynamics (CFD)

    SciTech Connect

    Covrig, Silviu D. [JLAB

    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.

  8. Designing high power targets with computational fluid dynamics (CFD)

    SciTech Connect

    Covrig, S. D. [Thomas Jefferson National Laboratory, Newport News, VA 23606 (United States)

    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 ?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 ?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.

  9. Theory for high gain, high power free electron lasers

    SciTech Connect

    Colson, W.B. (Berkeley Research Associates, Inc., CA (USA))

    1989-01-01

    In the past contracting period, the research on high gain, high power free electron lasers (FELs) has been fruitful. The findings have resulted in publications, presentations, and some important new research topics in progress. The work has been accomplished in close collaboration with the FEL physicists at LLNL including weekly visits to the LLNL Beam Research Building. The new research proposed is also coordinated closely with specific LLNL FEL project physicists, and the upcoming high-gain, high-power amplifier experiments during the next year on the Paladin FEL. The research includes analysis of the initial ELF experiments, identification of new FEL physics in Paladin at 5m length, electron beam distributions from future induction linacs, electron beam distributions in weak optical fields, a major FEL review paper, a simple understanding of FEL optical guiding, multimode analysis applied to single-pass FEL amplifiers, a LLNL review talk on FEL sidebands and electron distribution functions. 3 refs.

  10. Designing high power targets with computational fluid dynamics (CFD)

    NASA Astrophysics Data System (ADS)

    Covrig, S. 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 ?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 ?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.

  11. 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.

  12. 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.

  13. High power device for the electric safety of metallic structures

    Microsoft Academic Search

    Iosif Lingvay; Viorel Banu; Carmen Lingvay; Ioana Rauta; Mihai Apostolescu; Florin Stoian

    2001-01-01

    A hybrid high-power solid-state device, voltage limiter and having a fast switching rate, has been conceived and built. The device copes in forward polarization with hazardous overcurrent impulses up to 1800 A for 1s and 120 to 40 A-depending on the type-also for 1s, in reverse polarization. The device was checked at lightning impulses (20\\/8 ?s) at a peak current

  14. Analog predistortion linearizer for high-power RF amplifiers

    Microsoft Academic Search

    Jaehyok Yi; Youngoo Yang; Wonwoo Kang; Bumman Kim

    2000-01-01

    We have developed an analog predistortion linearizer for a high-power amplifier of a code-division multiple-access (CDMA) base station. To effectively suppress the spectral regrowth in the adjacent channels, the odd-order intermodulation distortions (IMDs) should be cancelled. To accomplish this purpose, we employed a predistorter, which can cancel the third and fifth IMDs independently. The implemented predistorter linearized the RF amplifier

  15. High power operational experience with the LANSCE Linac

    SciTech Connect

    Rybarcyk, Lawrence J [Los Alamos National Laboratory

    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.

  16. Recent advances in high-power microwave amplifiers

    SciTech Connect

    Reid, D.W.

    1988-01-01

    Recent advances in microwave amplifiers have increased efficiencies and power levels at frequencies from 0.3--150 GHz. These improvements have occurred in both solid-state and vacuum-tube systems. Of special note is the very high power device where power levels of 1 GW are routinely generated. This paper will review the latest results of these RandD efforts. 3 refs., 4 figs.

  17. High power fiber delivery for laser ignition applications.

    PubMed

    Yalin, Azer P

    2013-11-01

    The present contribution provides a concise review of high power fiber delivery research for laser ignition applications. The fiber delivery requirements are discussed in terms of exit energy, intensity, and beam quality. Past research using hollow core fibers, solid step-index fibers, and photonic crystal and bandgap fibers is summarized. Recent demonstrations of spark delivery using large clad step-index fibers and Kagome photonic bandgap fibers are highlighted. PMID:24514929

  18. High-power diode lasers for space communications - A review

    Microsoft Academic Search

    D. Botez

    1988-01-01

    A development status evaluation is presented for high power, 50-1000 mW diode lasers applicable to space communications; attention is given to current and prospective capabilities of monolithic single-element and few-element devices constituting phase-locked arrays, as well as to various more-than-10-element phase-locked arrays. Nonabsorbing mirror structures are employed to preclude facet degradation. Also noted are the prospects for development of hybrid

  19. High Power RF Heating in the LDX Experiment

    Microsoft Academic Search

    Michael Mauel; D. Garnier; M. Davis; J. Kesner; P. Michael; P. Woskov

    2010-01-01

    Exploration of higher-density plasmas created with high-power RF heating is key objective of the next phase of the LDX research programhttp:\\/\\/www.psfc.mit.edu\\/ldx\\/. This poster describes the use of a 1 MW HF Band (4 to 26 MHz) radio-frequency transmitter in a two-part program. First, we will evaluate axisymmteric (m = 0) antenna and match-box designs and make low-power 1 kW measurements.

  20. Epitaxy of High-Power Diode Laser Structures

    Microsoft Academic Search

    Markus Weyers; Arnab Bhattacharya; Frank Bugge; Arne Knauer

    2000-01-01

    Excellent semiconductor-material quality is an essential prerequisite for the fabrication of high-power diode lasers and laser\\u000a bars. This review discusses issues in the epitaxial growth of semiconductor materials and layer sequences that form the basis\\u000a for diode lasers. First, an overview of the material systems used for diode lasers with emission wavelengths extending from\\u000a the far-infrared to the blue range