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Sample records for high-power aluminum z-pinch

  1. Variation of high-power aluminum-wire array z-pinch dynamics with wire number, load mass, and array radius

    SciTech Connect

    Sanford, T.W.L.; Mock, R.C.; Marder, B.M.

    1997-12-01

    A systematic study of annular aluminum-wire z-pinches on the Saturn accelerator shows that the quality of the implosion, (as measured by the radial convergence, the radiated energy, pulse width, and power), increases with wire number. Radiation magnetohydrodynamic (RMHC) xy simulations suggest that the implosion transitions from that of individual wire plasmas to that of a continuous plasma shell when the interwire spacing is reduced below {approximately} 1.4 mm. In this plasma-shell regime, many of the global radiation and plasma characteristics are in agreement with those simulated by 2D-RMHC rz simulations. In this regime, measured changes in the radiation pulse width with variations in load mass and array radius are consistent with the simulations and are explained by the development of 2D fluid motion in the rz plane. Associated variations in the K-shell yield are qualitatively explained by simple radiation-scaling models.

  2. Variation of high-power aluminum-wire array Z-pinch dynamics with wire number, array radius, and load mass

    SciTech Connect

    Sanford, T.W.L.; Mock, R.C.; Marder, B.M.

    1997-06-01

    A systematic study of annular aluminum-wire z-pinches on the Saturn accelerator shows that the quality of the implosion, including the radiated power, increases with wire number. Radiation magnetohydrodynamic (RMEC) xy simulations suggest that the implosion transitions from that of individual wire plasmas to that of a continuous plasma shell when the interwire spacing is reduced below {approximately} 1.4 mm. In the plasma-shell regime, the experimental implosions exhibit 1D- and 2D-code characteristics as evidenced by the presence of a strong first and a weak second radiation pulse that correlates with a strong and weak radial convergence. In this regime, many of the radiation and plasma characteristics are in agreement with those simulated by 2D-RMHC rz simulations. Moreover, measured changes in the radiation pulse width with variations in array mass and radius are consistent with the simulations and are explained by the development of 2D fluid motion in the rz plane. Associated variations in the K-shell yield are qualitatively explained by simple K-shell radiation scaling models.

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

    SciTech Connect

    SANFORD,THOMAS W. L.

    2000-05-23

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

  5. Mass and wire number effects of long implosion time Aluminum Z-pinches on Saturn

    NASA Astrophysics Data System (ADS)

    Coverdale, C. A.; Deeney, C.; Lepell, P. D.; Sze, H.; Failor, B.; Coleman, P.; Whitney, K. G.; Thornhill, J. W.; Apruzese, J. P.; Davis, J.; Schneider, R.

    1999-11-01

    Aluminum K-shell emissions from long implosion time Z-pinches have been studied on the 7 MA Saturn accelerator. These experiments, motivated in part by the need to develop Z-pinch sources for the DECADE-Quad pulsed power driver, were designed to investigate the effects of wire number and mass on the Al K-shell radiation. The wire arrays were 40 mm in diameter and the wire number was varied from 32 to 282, holding the mass constant. In a separate scan, the load mass was varied from 400 to 2000 μg/cm, resulting in implosion times of 130 to 180 ns. K-shell yields greater than 60 kJ were measured with pulsewidths as short as 8 ns. These results will be compared with calculations and discussed within the context of K-shell scaling laws. Comparisons will also be made to short implosion time Al experiments performed on Saturn. *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-AC04-94Al85000.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  7. Use of the Pegasus Z pinch machine to study inertial instabilities in aluminum: a preliminary report

    SciTech Connect

    Chandler, E.; Egan, P.; Winer, K.; Stokes, J.; Fulton, R.D.; King, N.S.P.; Morgan, D.V.; Obst, A.W.; Oro, D.W.

    1997-06-13

    We have designed a target to probe the use of the Pegasus Z-Pinch machine to image inertial instabilities that develop on cylindrical- convergent material interfaces. The Z-pinch is tailored so that the target, soft Al 1100-O, remains solid; instabilities and inertial effects are seeded by wire inclusions of different densities. We present here the first images and preliminary results from this experiment.

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

    SciTech Connect

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

    1992-11-30

    We describe {ital 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 energy from a pulsed-power generator to a micron-diameter-sized plasma channel.

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

    SciTech Connect

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

    2012-10-15

    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 ({approx}10-40 eV) plasmas than emission spectra ({approx}350-500 eV).

  10. X-ray absorption spectroscopy of aluminum z-pinch plasma with tungsten backlighter planar wire array sourcea)

    NASA Astrophysics Data System (ADS)

    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).

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

    SciTech Connect

    Ampleford, D. J. 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.; Chong, Y.-K.; Clark, R. W.; Ouart, N.; Thornhill, J. W.; Giuliani, J.; Apruzese, J. P.

    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-α). 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.

  12. Enhanced [ital Z] pinch using an externally applied magnetic field to stabilize the implosion of an aluminum plasma jet onto a coaxial wire

    SciTech Connect

    Edison, N.S.; Etlicher, B.; Chuvatin, A.S.; Attelan, S. ); Aliaga, R. )

    1993-11-01

    We have performed [ital Z]-pinch experiments in which an aluminum plasma jet is imploded onto a coaxial, micrometer-diameter wire. X-ray pinhole images and temporally resolved x-ray data indicate that energy is initially supplied to the aluminum plasma jet, then transferred to the wire at the peak compression of the implosion. When a dc magnetic field is applied axially, growth of instabilities of the imploding aluminum plasma are reduced, and the production of x rays from the embedded wire is enhanced. These experiments demonstrate that an imploding plasma liner efficiently couples energy from a pulsed power generator into a micrometer-sized-diameter channel.

  13. X-ray backlighting density measurements of tungsten and aluminum wire and wire array z-pinches

    SciTech Connect

    Hammer, D.A.; Pikuz, S.A.; Shelkovenko, T.A.; Greenly, J.B.; Sinars, D.B.; Mingaleev, A.R.

    1999-07-01

    Calibrated density measurements in both the coronal plasmas and dense cores of exploding W wire and wire array Z-pinches, powered by the {approximately}450 kA, 100 ns XP-pulser at Cornell University, have been made using two-frame x-ray backlighting in conjunction with known thickness W step wedges. The backlighting images are made by Mo wire X-pinch radiation filtered by 12.5 {micro}m Ti impinging upon a sandwich of films (Micrat VR, Kodak GWL, Kodak DEF) which have different sensitivities to increase the dynamic range of the method. A W step wedge filter is placed in front of the films, giving absolute line density calibration of each exposure with estimated errors ranging from 20 to 50%. Assuming x-ray absorption by the W plasma is the same as for the solid material, the authors are able to measure W areal densities from 3.2 x 10{sup 19} to 2 x 10{sup 17}/cm{sup 2}. These can be converted to number density assuming azimuthal symmetry. For example, for an exploded 7.5 {micro}m wire with a 15--20 {micro}m diameter dense core and a 1 mm corona diameter, the implied W volume density ranges from 2x10{sup 18} to over 10{sup 22}/cm{sup 3}. Integration of the line density gives an estimate of the fraction of the wire mass in the corona and core. For example, with 100 kA peak current in a single 7.5 {micro}m W wire, {approximately}70% (>90%) of the W mass is in the corona after 53 ns (61 ns). The authors also observe that the corona has large, roughly axisymmetric axial nonuniformity both in radius and in mass density. In addition, the coronal plasma contains more of the W mass, expands faster and is more uniform when the wire is surface-cleaned by preheating. In arrays of 2--8 wires with the same 100 kA total current, detectable coronal plasma appears after 25--35 ns, and much of it is swept toward the center of the array, forming a dense channel. The portion of the initial wire mass in the coronal plasma increases with smaller wire diameter and decreases with greater

  14. 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.

  15. Experimental investigation of the properties and phase state of thick aluminum surfaces pulsed to megagauss level magnetic field in a Z-pinch geometry

    NASA Astrophysics Data System (ADS)

    Awe, Thomas J.

    Thermal transformation to plasma of an aluminum surface pulsed to multi-megagauss magnetic field is observed to occur when the surface field reaches a threshold level of 2.2 MG. Magnetic field (B) is pulsed on the surface of cylindrical metallic rods. Rods are thick ---with radii (R) exceeding the magnetic field penetration depth (deltaB). Ohmic heating is confined to a skin layer, with deltaB determined by diffusion and hydrodynamic processes. Initial rod diameters (D0) ranging from 2.00 to 0.50 mm are pulsed with 1.0 MA peak current by the Zebra z-pinch. Due to Zebra's high transmission line impedance (1.9 ohm), the current waveform is insensitive to D0. The Zebra current, I( t), consistently rises exponentially to 100 kA (with rise time tau=13 ns), and then linearly from 100 to 900 kA for 70 ns, with dI/d t = 1.1x1013 A/s, to a maximum current of 1.0 MA. By altering D0, a variety of magnetic field and current density profiles are examined. For D0 of 2.00 and 0.50 mm, magnetic field rise rates ∂B/∂ t) vary from 30 and 80 MG/mus, and peak surface fields reach 1.5 and 4 MG, respectively. Novel contact configurations and load surface profiles mitigate plasma formation from contact arcing or electric-field-driven electron avalanche, ensuring that plasma forms thermally---a result of ohmic or compression heating. Aluminum plasma is observed through a variety of independently measured phenomena. First, for rod surfaces pulsed above the magnetic field threshold (Bs > Bthreshold = 2.2 MG), multi-eV brightness temperatures (TBB) are observed, clearly indicating plasma for aluminum. For example, peak TBB reach 20 and 36 eV for 1.00 and 0.50 mm rods, respectively. Plasma forms at lower current and reaches higher temperatures as D0 is decreased. Second, aluminum ion species are distinguished via extreme ultraviolet (EUV) spectroscopy. Line spectra from Al3+ and Al4+ ions are obtained. The average ion charge and line ratios depend strongly upon temperature, and taking the

  16. 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.

  17. Development of a Z-pinch-driven ICF hohlraum concept on Z

    SciTech Connect

    Cuneo, M.E.; Porter, J.L. Jr.; Vesey, R.A.

    1999-07-01

    Recent development of high power z-pinches (> 150 MW) on the Z driver has permitted the study of high-temperature, radiation-driven hohlraums. Three complementary, Z-pinch source-hohlraum-ICF capsule configurations are being developed to harness the x-ray output of these Z-pinch's. These are the dynamic-hohlraum, static-wall hohlraum, and Z-pinch-driven hohlraum concepts. Each has different potential strengths and concerns. In this paper, the authors report on the first experiments with the Z-pinch-driven hohlraum (ZPDH) concept. A high-yield ICF capsule design for this concept appears feasible, when driven by z-pinches from a 60 MA-class driver. Initial experiments characterize the behavior of the spoke array on Z-pinch performance and x-ray transmission, and the uniformity of radiation flux incident on a foam capsule in the secondary, for a single-sided drive. Measurements of x-ray wall re-emission power and spectrum, radiation temperatures, spoke-plasma location, and drive uniformity will be presented and compared with 0-D energetics, 2-D Lasnex rad-hydro, and 3-D radiosity calculations of energy transport and drive uniformity.

  18. Formation of a sheared flow Z pinch

    NASA Astrophysics Data System (ADS)

    Golingo, R. P.; Shumlak, U.; Nelson, B. A.

    2005-06-01

    The ZaP Flow Z-Pinch project is experimentally studying the effect of sheared flows on Z-pinch stability. It has been shown theoretically that when dVz/dr exceeds 0.1kVA the kink (m =1) mode is stabilized. [U. Shumlak and C. W. Hartman, Phys. Rev. Lett. 75, 3285 (1995).] Z pinches with an embedded axial flow are formed in ZaP with a coaxial accelerator coupled with a 1m assembly region. Long-lived, quiescent Z pinches are generated throughout the first half cycle of the current. During the initial plasma acceleration phase, the axial motion of the current sheet is consistent with snowplow models. Magnetic probes in the assembly region measure the azimuthal modes of the magnetic field. The amplitude of the m =1 mode is proportional to the radial displacement of the Z-pinch plasma current. The magnetic mode levels show a quiescent period which is over 2000 times the growth time of a static Z pinch. The axial velocity is measured along 20 chords through the plasma and deconvolved to provide a radial profile. Using data from multiple pulses, the time evolution of the velocity profile is measured during formation, throughout the quiescent period, and into the transition to instability. The evolution shows that a sheared plasma flow develops as the Z pinch forms. Throughout the quiescent period, the flow shear is greater than the theoretically required threshold for stability. As the flow shear decreases, the magnetic mode fluctuations increase. The coaxial accelerator provides plasma throughout the quiescent period and may explain the evolution of the velocity profile and the sustainment of the flow Z pinch.

  19. 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.

  20. The physics of fast Z pinches

    SciTech Connect

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

    1998-07-01

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

  1. Spectroscopic study in Z-pinch discharge

    SciTech Connect

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

    1995-12-31

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

  2. Ionization dynamics of a single wire z-pinch

    NASA Astrophysics Data System (ADS)

    Johnston, Mark Darren

    This thesis explored the ionization dynamics of a single wire z-pinch. Experiments were conducted on fine wires of aluminum, copper, silver, and tungsten ranging in diameter from 7.5--50mum with lengths of 2.5cm. These wires were subjected to a pulsed current of ˜2kA, 500ns half-cycle from a spark-gap triggered, negatively-charged capacitor bank discharge. The results of this thesis are divided into three parts which cover the entire dynamic evolution of the wires during the first ˜500ns of the current pulse. The first part examined surface impurity evolution and its contribution to the voltage collapse and initial plasma formation. It was discovered that hydrocarbon impurities contribute significantly to the initial plasma formation, for all wires studied, and that high ionization states of carbon (CIII and CIV) are present at the point of the voltage collapse. The second portion of the thesis dealt with laser imaging and the observation of instability growth at the core/corona boundary of expanding z-pinch wire plasmas. From the increased sensitivity of the resonant XeCl excimer laser diagnostics, it was determined that, for aluminum wires, these instabilities were consistent with a hydrodynamic Rayleigh-Taylor instability of a decelerating plasma plume front. The third portion of the thesis focused on potential seeding mechanisms for instability growth in single wire z-pinches and their relevance to wire array experiments. It was observed in copper wires that do pre-heating of wires caused surface alterations due to recrystallization. It was also discovered, during the course of these studies, that electrical current pulses on the timescale of the experimental pulse (500ns half-cycle) could also alter the surface structure of copper wires and lead to coronal instabilities. Finally, preliminary investigations into the possibility of crystal/grain growth behavior in tungsten wires is given, along with the idea of using potassium doped tungsten wires as a means

  3. Z-Pinch Driven Isentropic Compression for Inertial Fusion

    SciTech Connect

    Asay, J.R.; Hall, C.A.; Holland, K.G.; Slutz, S.A.; Spielman, R.B.; Stygar, W.A.

    1999-02-01

    The achievement of high gain with inertial fusion requires the compression of hydrogen isotopes to high density and temperatures. High densities can be achieved most efficiently by isentropic compression. This requires relatively slow pressure pulses on the order of 10-20 nanoseconds; however, the pressure profile must have the appropriate time. We present 1-D numerical simulations that indicate such a pressure profile can be generated by using pulsed power driven z pinches. Although high compression is calculated, the initial temperature is too low for ignition. Ignition could be achieved by heating a small portion of this compressed fuel with a short (-10 ps) high power laser pulse as previously described. Our 1-D calculations indicate that the existing Z-accelerator could provide the driving current (-20 MA) necessary to compress fuel to roughly 1500 times solid density. At this density the required laser energy is approximately 10 kJ. Multidimensional effects such as the Rayleigh-Taylor were not addressed in this brief numerical study. These effects will undoubtedly lower fuel compression for a given chive current. Therefore it is necessary to perform z-pinch driven compression experiments. Finally, we present preliminary experimental data from the Z-accelerator indicating that current can be efficiently delivered to appropriately small loads (- 5 mm radius) and that VISAR can be used measure high pressure during isentropic compression.

  4. 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.

  5. Fusion in a staged Z-pinch

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  6. Breakeven Fusion in Staged Z Pinch

    NASA Astrophysics Data System (ADS)

    Rahman, Hafiz; Ney, Paul; Rostoker, Norman; Wessel, Frank

    2008-03-01

    We are studying the prospect for breakeven thermonuclear fusion considering a Mega joule (MJ) class, 100 ns, impulse generator using a modified version of MACH2, a 2-1/2 D, radiation-code. The load is a cylindrical, xenon plasma shell that implodes radially onto a co-axial, deuterium-tritium plasma target. Optimized plasma density and pinch radius lead to a fusion-energy output that is many times the stored capacitor bank energy. In this ``Staged Z-pinch'' shock fronts form that preheat the DT plasma to several hundred eV, before adiabatic compression. During compression, the Xe liner becomes Rayleigh-Taylor (RT) unstable while the DT target remains stable. Proper selection of the initial pinch radius and plasma density is crucial for optimum implosion efficiency.

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

    SciTech Connect

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

    2004-11-01

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

  8. The high density Z-pinch

    NASA Astrophysics Data System (ADS)

    McCall, G. H.

    During the past few years techniques have been developed for producing pinches in solid deuterium. The conditions which exist in these plasmas are 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. 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. It is argued 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 the status of the high density Z-pinch experiments at laboratories around the world is presented, and some of the calculational and experimental results described. Remarks are confined to recent work on the high density pinch.

  9. Staged Z-pinch for Fusion

    NASA Astrophysics Data System (ADS)

    Wessel, Frank; Rahman, Hafiz; Ney, Paul; Darling, Tim; McKee, Erik; Covington, Aaron; Beg, Farhat; Valenzuela, Julio; Narkis, Jeff; Presura, Radu

    2015-11-01

    The Staged Z-pinch (SZP) is configured as a plasma shell imploding onto an uniform, plasma fill (50:50 Deuterium:Tritium); the pinch is pre-magnetized, with an axial Bz field. Gas-puff experiments, at the University of California, Irvine, 1.25 MA, 1.25 μs, and 50 kJ, demonstrated that the implosion was stable, as primary (DD) and secondary (DT) neutrons were produced at peak compression. Subsequent analysis accounts for the stability and neutron yield, indicating that the SZP implosion is magneto-inertial, shock-driven, with magneto-sonic shocks in the liner and ordinary (sonic) shocks in the target. The shock waves preheat the target, as a stable, current-carrying, shock front forms at the interface. Near-term, the SZP team will test pinch loads on the 1 MA, 130 ns, 100 kJ University of Nevada, Reno, Nevada Terawatt, Zebra Facility. This paper details the context and our specific plans for the upcoming experiments, as well as our recent simulations predicting breakeven fusion on existing devices. Funded by the US Department of Energy, ARPA-E, Control Number 1184-1527.

  10. About plasma points' generation in Z-pinch

    SciTech Connect

    Afonin, V. I.; Potapov, A. V.; Lazarchuk, V. P.; Murugov, V. M.; Senik, A. V.

    1997-05-05

    The streak tube study results (at visible and x-ray ranges) of dynamics of fast Z-pinch formed at explosion of metal wire in diode of high current generator are presented. Amplitude of current in the load reached {approx}180 kA at increase time {approx}50 ns. The results' analysis points to capability of controlling hot plasma points generation process in Z-pinch.

  11. 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.

  12. 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.

  13. Z-Pinch Pulsed Plasma Propulsion Technology Development

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  14. A Z-Pinch Driven Fusion Reactor Concept

    NASA Astrophysics Data System (ADS)

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

    1999-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    SciTech Connect

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

    2010-08-15

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

  17. Seeded perturbations in wire array Z-Pinches.

    SciTech Connect

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

    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.

  18. Rotating plasma disks in dense Z-pinch experiments

    SciTech Connect

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

    2014-12-15

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

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

    SciTech Connect

    Appelbe, Brian; Chittenden, Jeremy

    2009-01-21

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

  20. Electron temperature diagnostics of aluminium plasma in a z-pinch experiment at the “QiangGuang-1" facility

    NASA Astrophysics Data System (ADS)

    Li, Mo; Wu, Jian; Wang, Liang-Ping; Wu, Gang; Han, Juan-Juan; Guo, Ning; Qiu, Meng-Tong

    2012-12-01

    Two curved crystal spectrometers are set up on the “QiangGuang-1" generator to measure the z-pinch plasma spectra emitted from planar aluminum wire array loads. Kodak Biomax-MS film and an IRD AXUVHS5# array are employed to record time-integrated and time-resolved free-bound radiation, respectively. The photon energy recorded by each detector is ascertained by using the L-shell lines of molybdenum plasma. Based on the exponential relation between the continuum power and photon energies, the aluminum plasma electron temperatures are measured. For the time-integrated diagnosis, several “bright spots" indicate electron temperatures between (450 eV ~ 520 eV) ± 35%. And for the time-resolved ones, the result shows that the electron temperature reaches about 800 eV ± 30% at peak power. The system satisfies the demand of z-pinch plasma electron temperature diagnosis on a ~ 1 MA facility.

  1. The Dense Z-Pinch Programme at Imperial College

    NASA Astrophysics Data System (ADS)

    Haines, M. G.

    1994-03-01

    An extensive programme of research, both experimental and theoretical, into the stability and dynamics of Z-pinches has led to the funding of the DZP Project to study both radiative collapse of Z-pinch plasmas and pinches close to thermonuclear fusion conditions. The MAGPIE (Mega-Ampere Generator for Plasma Implosion Experiments) generator (2.4MV, 336kJ, 200ns) is now being commissioned ready for Z-pinch experiments commencing this summer. The design of the generator has been determined by the perceived requirements demanded by consideration of (a) fusion conditions with end losses to electrodes, (b) radiative collapse at currents well above the Pease-Braginskii limit, and (c) stability studies particularly under large ion Larmor radius conditions. As a result, and in contrast to other generators in the >1TW class this has a long pulse length (200ns) and a final line impedance of 1.25 ohm. The stability regimes together with theoretical and experimental results are reviewed in the framework of the I4a-N diagram. Our understanding (albeit incomplete) of other phenomena characteristic of Z-pinches, namely the formation of electron beams, dense spots of intense X-ray emission, ion beams and filaments will be summarised.

  2. Z-pinch experiments on Saturn at 30 TW

    NASA Astrophysics Data System (ADS)

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

    1989-12-01

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

  3. Z-pinch experiments on Saturn at 30 TW

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

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

    2003-10-01

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

  5. X-ray absorption spectroscopy measurements of thin foil heating by Z-pinch radiation.

    PubMed

    MacFarlane, J J; Bailey, J E; Chandler, G A; Deeney, C; Douglas, M R; Jobe, D; Lake, P; Nash, T J; Nielsen, D S; Spielman, R B; Wang, P; Woodruff, P

    2002-10-01

    Absorption spectroscopy measurements of the time-dependent heating of thin foils exposed to intense z-pinch radiation sources are presented. These measurements and their analysis provide valuable benchmarks for, and insights into, the radiative heating of matter by x-ray sources. Z-pinch radiation sources with peak powers of up to 160 TW radiatively heated thin plastic-tamped aluminum foils to temperatures approximately 60 eV. The foils were located in open slots at the boundary of z-pinch hohlraums surrounding the pinch. Time-resolved Kalpha satellite absorption spectroscopy was used to measure the evolution of the Al ionization distribution, using a geometry in which the pinch served as the backlighter. The time-dependent pinch radius and x-ray power were monitored using framing camera, x-ray diode array, and bolometer measurements. A three-dimensional view factor code, within which one-dimensional (1D) radiation-hydrodynamics calculations were performed for each surface element in the view factor grid, was used to compute the incident and reemitted radiation flux distribution throughout the hohlraum and across the foil surface. Simulated absorption spectra were then generated by postprocessing radiation-hydrodynamics results for the foil heating using a 1D collisional-radiative code. Our simulated results were found to be in good general agreement with experimental x-ray spectra, indicating that the spectral measurements are consistent with independent measurements of the pinch power. We also discuss the sensitivity of our results to the spectrum of the radiation field incident on the foil, and the role of nonlocal thermodynamic equilibrium atomic kinetics in affecting the spectra. PMID:12443339

  6. 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

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

    NASA Astrophysics Data System (ADS)

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

    2002-11-01

    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 the short-pulse laser [Kodama et al., Nature 412, 798 (2001)]. In experiments on the Z accelerator at Sandia, we are exploring a fast ignitor hohlraum geometry uniquely adapted to fuel compression with a single-sided z-pinch radiation drive [Hanson et al., Phys. Plasmas 9, 2173 (2002)]. In this geometry, a hemispherical capsule mounted on a pedestal (short-pulse laser channel) is symmetrically imploded in a cylindrical secondary hohlraum heated by a single-wire-array z-pinch. Z-Beamlet point projection backlighter images of initial hemispherical capsule implosions on Z will be presented.

  8. Resolving microstructures in Z pinches with intensity interferometry

    SciTech Connect

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

    2014-03-15

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

  9. Modeling Z-Pinch implosions in two dimensions

    SciTech Connect

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

    1997-12-31

    Ideally, simulations of Z-Pinch implosions should provide useful information about important physics processes underlying observed experimental results and provide design capabilities for future experiments. With this goal the authors have developed a methodology for simulating hollow Z-Pinches in two dimensions and applied it to experiments conducted on the Pegasus I and Pegasus II capacitor banks, the Procyon explosion generator system, and the Saturn and PBFA-Z accelerators. In comparisons with experimental results the simulations have reproduced important features of the current drive, spectrum, radiation pulse shape, peak power and total radiated energy. Comparison of the instability development in the simulations with visible light framing camera photos has shown a close correlation with the observed instability wavelengths and amplitudes. Using this methodology the authors are analyzing recent Saturn and PBFA-Z experiments and applying the 2-D modeling in developing applications such as the dynamic hohlraum.

  10. Optimization of Capsule Symmetry in Z-Pinch Driven Hohlraums

    NASA Astrophysics Data System (ADS)

    Vesey, R. A.; Cuneo, M.; Hanson, D.; Porter, J.; Mehlhorn, T.; Ruggles, L.; Simpson, W.; Vargas, M.; Hammer, J.; Landen, O.

    1999-11-01

    The uniformity of the radiation flux incident on the capsule is a critical issue for indirect drive fusion using the z-pinch driven hohlraum high-yield concept(J.H. Hammer et al., Phys. Plas. 6), 2129 (1999).. Experiments on the Z accelerator at Sandia have demonstrated the ability to diagnose the uniformity of the flux striking a foam ball (surrogate capsule)(P.A. Amendt et al., Phys. Plas. 4), 1862 (1997); S.G. Glendinning et al. Rev. Sci. Instrum. 70, 536 (1999).. These single-sided drive experiments have been modeled using radiosity and radiation-hydrodynamics codes, yielding agreement with the measured ablation rate vs. angle on the foam ball. Flux uniformity at the 1-2% level needed for high-convergence capsule implosions requires a 2-sided drive (top and bottom z-pinch) configuration. Constrained optimization methods have identified hohlraum geometries with improved symmetry.

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

    SciTech Connect

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

    1998-08-01

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

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

    SciTech Connect

    Sanford, T.W.L.; Mock, R.C.; Marder, B.M.

    1997-12-31

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

  13. Measurement of Radiation Symmetry in Z-Pinch Driven Hohlraums

    NASA Astrophysics Data System (ADS)

    Hanson, David L.

    2001-10-01

    The z-pinch driven hohlraum (ZPDH) is a promising approach to high yield inertial confinement fusion currently being characterized in experiments on the Sandia Z accelerator [1]. In this concept [2], x rays are produced by an axial z-pinch in a primary hohlraum at each end of a secondary hohlraum. A fusion capsule in the secondary is imploded by a symmetric x-ray flux distribution, effectively smoothed by wall reemission during transport to the capsule position. Capsule radiation symmetry, a critical issue in the design of such a system, is influenced by hohlraum geometry, wall motion and time-dependent albedo, as well as power balance and pinch timing between the two z-pinch x-ray sources. In initial symmetry studies on Z, we used solid low density burnthrough spheres to diagnose highly asymmetric, single-sided-drive hohlraum geometries. We then applied this technique to the more symmetric double z-pinch geometry [3]. As a result of design improvements, radiation flux symmetry in Z double-pinch wire array experiments now exceeds the measurement sensitivity of this self-backlit foam ball symmetry diagnostic (15% max-min flux asymmetry). To diagnose radiation symmetry at the 2 - 5% level attainable with our present ZPDH designs, we are using high-energy x rays produced by the recently-completed Z-Beamlet laser backlighter for point-projection imaging of thin-wall implosion and symmetry capsules. We will present the results of polar flux symmetry measuremets on Z for several ZPDH capsule geometries together with radiosity and radiation-hydrodynamics simulations for comparison. [1] M. E. Cuneo et al., Phys. Plasmas 8,2257(2001); [2] J. H. Hammer et al., Phys. Plasmas 6,2129(1999); [3] D. L. Hanson et al., Bull. Am. Phys. Soc. 45,360(2000).

  14. Dynamics of conical wire array Z-pinch implosions

    SciTech Connect

    Ampleford, D. J.; Lebedev, S. V.; Bland, S. N.; Bott, S. C.; Chittenden, J. P.; Jennings, C. A.; Kantsyrev, V. L.; Safronova, A. S.; Ivanov, V. V.; Fedin, D. A.; Laca, P. J.; Yilmaz, M. F.; Nalajala, V.; Shrestha, I.; Williamson, K.; Osborne, G.; Haboub, A.; Ciardi, A.

    2007-10-15

    A modification of the wire array Z pinch, the conical wire array, has applications to the understanding of wire array implosions and potentially to pulse shaping relevant to inertial confinement fusion. Results are presented from imploding conical wire array experiments performed on university scale 1 MA generators--the MAGPIE generator (1 MA, 240 ns) at Imperial College London [I. H. Mitchell et al., Rev. Sci Instrum. 67, 1533 (1996)] and the Nevada Terawatt Facility's Zebra generator (1 MA, 100 ns) at the University of Nevada, Reno [B. Bauer et al., in Dense Z-Pinches, edited by N. Pereira, J. Davis, and P. Pulsifer (AIP, New York, 1997), Vol. 409, p. 153]. This paper will discuss the implosion dynamics of conical wire arrays. Data indicate that mass ablation from the wires in this complex system can be reproduced with a rocket model with fixed ablation velocity. Modulations in the ablated plasma are present, the wavelength of which is invariant to a threefold variation in magnetic field strength. The axial variation in the array leads to a zippered precursor column formation. An initial implosion of a magnetic bubble near the cathode is followed by the implosion zippering upwards. Spectroscopic data demonstrating a variation of plasma parameters (e.g., electron temperature) along the Z-pinch axis is discussed, and experimental data are compared to magnetohydrodynamic simulations.

  15. Stabilization in the ZaP Flow Z-Pinch

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; Blakely, J. M.; Chan, B.-J.; Golingo, R. P.; Knecht, S. D.; Nelson, B. A.; Oberto, R. J.; Sybouts, M. R.; Vogman, G. V.; Den Hartog, D. J.

    2009-06-01

    The ZaP flow Z-pinch experiment at the University of Washington investigates the innovative plasma confinement concept of using sheared flows to stabilize an otherwise unstable configuration. The ZaP experiment generates an axially flowing Z-pinch that is 1 m long with a 1 cm radius with a coaxial accelerator coupled to a pinch assembly chamber. Magnetic probes measure the fluctuation levels of the azimuthal modes m = 1, 2, and 3. After assembly, the plasma is magnetically confined for an extended quiescent period where the mode activity is significantly reduced. Experimental measurements show a sheared flow profile that is coincident with the low magnetic fluctuations during the quiescent period. Recent experimental modifications produce more energetic Z-pinch plasmas that exhibit the same general behavior. The plasma equilibrium is characterized with a suite of diagnostics that measure the plasma density, magnetic field, ion and electron temperatures, in addition to plasma flow. The equilibrium is shown to satisfy radial force balance.

  16. 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 (˜1μs) Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses (≪1μs) 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

  17. Enhanced energy coupling and x-ray emission in Z-pinch plasma implosions

    NASA Astrophysics Data System (ADS)

    Whitney, K. G.; Thornhill, J. W.; Apruzese, J. P.; Davis, J.; Deeney, C.; Coverdale, C. A.

    2004-08-01

    Recent experiments conducted on the Saturn pulsed-power generator at Sandia National Laboratories [R. B. Spielman et al., in Proceedings of the Second International Conference on Dense Z Pinches, Laguna Beach, CA, 1989, edited by N. R. Pereira, J. Davis, and N. Rostoker (American Institute of Physics, New York, 1989), p. 3] have produced large amounts of x-ray output, which cannot be accounted for in conventional magnetohydrodynamic (MHD) calculations. In these experiments, the Saturn current had a rise time of ~180 ns in contrast to a rise time of ~60 ns in Saturn's earlier mode of operation. In both aluminum and tungsten wire-array Z-pinch implosions, 2-4 times more x-ray output was generated than could be supplied according to one-dimensional (1D) magnetohydrodynamic calculations by the combined action of the j×B acceleration forces and ohmic heating (as described by a classical Braginskii resistivity). In this paper, we reexamine the problem of coupling transmission line circuits to plasma fluid equations and derive expressions for the Z-pinch load circuit resistance and inductance that relate these quantities in a 1D analysis to the surface resistivity of the fluid, and to the magnetic field energy that is stored in the vacuum diode, respectively. Enhanced energy coupling in this analysis, therefore, comes from enhancements to the surface resistivity, and we show that plasma resistivities approximately three orders of magnitude larger than classical are needed in order to achieve energy inputs that are comparable to the Saturn experiment x-ray outputs. Large enhancements of the plasma resistivity increase the rate of magnetic field and current diffusion, significantly modify the qualitative features of the MHD, and raise important questions as to how the plasma fluid dynamics converts enhanced energy inputs into enhanced x-ray outputs. One-dimensional MHD calculations in which resistivity values are adjusted phenomenologically are used to illustrate how

  18. Implosion dynamics of wire-array z-pinches on the COBRA accelerator

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

    Experimental results characterizing wire-array z-pinch implosion dynamics on the 1-MA, 100-ns rise time COBRA pulsed power generator are presented. Diagnostics fielded include an optical streak camera, a time-gated XUV framing camera, a laser shadowgraph system, filtered time-integrated pinhole cameras, a focusing x-ray spectrometer with spatial resolution (FSSR), a load voltage monitor, a faraday cup, a bolometer, silicon diodes and diamond photoconducting detectors (PCDs). The load geometries investigated in this set of experiments include cylindrical arrays ranging from 6 to 16 mm in diameter, and consisting of 8, 16, or 32 wires of either aluminum (Al) or tungsten (W). The data produced by the entire suite of diagnostics are analyzed and presented to provide an overall picture of implosion dynamics and timing on COBRA. In particular, data fitting to various implosion trajectory models, as well as x-ray pulse shape dependencies on various loads and implosion characteristics are presented and discussed.

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

    SciTech Connect

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

    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.

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

    SciTech Connect

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

    2009-01-21

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

  1. Computational modeling of wall-supported dense Z-pinch

    SciTech Connect

    Sheehey, P.; Gerwin, R.A.; Kirkpatrick, R.

    1997-11-01

    In our previous computational modeling of deuterium-fiber-initiated Z-pinches intended for ohmic self-heating to fusion conditions, instability-driven expansion caused densities to drop far below those desired for fusion applications; such behavior has been observed on experiments such as Los Alamos` HDZP-II. A new application for deuterium-fiber-initiated Z-pinches is Magnetized Target Fusion (MTF), in which a preheated and magnetized target plasma is hydrodynamically compressed, by a separately driven liner, to fusion conditions. Although the conditions necessary for suitable target plasma--density O(10{sup 18} cm{sup -3}), temperature O(100 eV), magnetic field O(100 kG)--are less extreme than those required for the previous ohmically heated fusion scheme, the plasma must remain magnetically insulated and clean long enough to be compressed by the imploding liner to fusion conditions, e.g., several microseconds. A fiber-initiated Z-pinch in a 2-cm-radius, 2-cm long conducting liner has been built at Los Alamos to investigate its suitability as an MTF target plasma. Two-dimensional magnetohydrodynamic modeling of this experiment shows early instability similar to that seen on HDZP-II; however, when plasma finds support and stabilization at the outer radial wall, a relatively stable profile forms and persists. Comparison of experimental results and computations, and computational inclusion of additional experimental details is being done. Analytic and computational investigation is also being done on possible instability-driven cooling of the plasma by Benard-like convective cells adjacent to the cold wall.

  2. Z-Pinch fusion-based nuclear propulsion

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

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

    SciTech Connect

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

    2014-12-15

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

  4. 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

  5. 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.

  6. Increasing Z-pinch vacuum hohlraum capsule coupling efficiency.

    SciTech Connect

    Callahan, Debbie; Vesey, Roger Alan; Cochrane, Kyle Robert; Nikroo, A.; Bennett, Guy R.; Schroen, Diana Grace; Ruggles, Laurence E.; Porter, John L.; Streit, Jon; Mehlhorn, Thomas Alan; Cuneo, Michael Edward

    2004-11-01

    Symmetric capsule implosions in the double-ended vacuum hohlraum (DEH) on Z have demonstrated convergence ratios of 14-21 for 2.15-mm plastic ablator capsules absorbing 5-7 kJ of x-rays, based on backlit images of the compressed ablator remaining at peak convergence [1]. Experiments with DD-filled 3.3-mm diameter capsules designed to absorb 14 kJ of x-rays have begun as an integrated test of drive temperature and symmetry, complementary to thin-shell symmetry diagnostic capsules. These capsule implosions are characterized by excellent control of symmetry (< 3% time-integrated), but low hohlraum efficiency (< 2%). Possible methods to increase the capsule absorbed energy in the DEH include mixed-component hohlraums, large diameter foam ablator capsules, transmissive shine shields between the z-pinch and capsule, higher spoke electrode x-ray transmission, a double-sided power feed, and smaller initial radius z-pinch wire arrays. Simulations will explore the potential for each of these modifications to increase the capsule coupling efficiency for near-term experiments on Z and ZR.

  7. D-D fusion experiments using fast z pinches

    SciTech Connect

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

    1994-04-01

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

  8. D-D fusion experiments using fast Z pinches

    SciTech Connect

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

    1998-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-01-01

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

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

    SciTech Connect

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

    2006-01-05

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

  11. The Study of a Fibre Z-Pinch

    NASA Astrophysics Data System (ADS)

    Klir, Daniel

    2007-03-01

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

  12. High gain fusion in a Staged Z-pinch

    NASA Astrophysics Data System (ADS)

    Ney, Paul; Rahman, Hafiz; Wessel, Frank; Presura, Radu

    2013-10-01

    The implosion of a Staged Z-pinch is simulated for the Sandia National Laboratories, ZR accelerator. The pinch is comprised of a silver (Ag) plasma shell, 3-mm outer radius, 0.01-cm thick, imploding onto a uniform fill (target) of deuterium-tritium (DT); the Z-R parameters are: 130 ns, 27 MA, 22 MJ; the 2-1/2 D, radiation-MHD code is MACH2. Magnetosonic shock waves generated during implosion propagate at different speeds in the liner and target, producing a shock front at the interface, and a conduction channel ahead of the liner. The interface remains stable even as the outer-surface of the liner is RT unstable. At peak compression target plasma hot spots trigger ignition with a fusion yield of 200 MJ and a net-energy gain approaching 10. The stability remains robust and the gain is unaffected for perturbations ranging from 2-5%.

  13. Dense plasma in Z-pinches and the plasma focus

    NASA Astrophysics Data System (ADS)

    Haines, M. G.

    1981-04-01

    Studies of the plasma focus, which after its three-dimensional compression closely resembles a Z-pinch, have shown that an electron temperature of 1 keV can be achieved in a narrow filament. Of great interest is the very high neutron yield, up to one trillion neutrons per discharge, which greatly exceeds that of any other fusion device. The origin of the neutrons is still a matter for research, as under different conditions there is evidence of intense electron and ion beams, instabilities, turbulence, and filamentations. All of these phenomena seem to be closely correlated to the neutron production which may not be thermonuclear in origin at all. An investigation is conducted of the physical processes that could be playing an important role in this case. A simplified interpretation of the phenomena could be that at a high line density the plasma focus is violently MHD unstable, but can form reconnecting bubbles.

  14. Light detonation wave in a cylindrical Z-pinch

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  15. Instability Control in a Staged Z-pinch

    SciTech Connect

    WESSEL, Frank J

    2011-04-22

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

  16. Suppression of Rayleigh-Taylor instabilities in Z-pinches

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    Experiments on studying the stability of Z-pinch compression were carried out at a current of 450 kA with a build-up time of 450 ns. The plasma shell of the pinches was formed by evaporating the electrode material in the process of vacuum arc burning. The Rayleigh-Taylor (RT) instabilities were suppressed using the regime of arc combustion on the surface of one of the electrodes in the high-voltage gap in which the pinch was positioned. As a result of free plasma discharge, the radial density distribution was formed such that the plasma concentration increased from the outer boundary to the shell axis. The experiments demonstrated that such an initial radial density distribution almost completely suppresses of the RT instability.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  18. 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.

  19. Enhancement of X-ray Production in Z-Pinch Plasmas Using Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Edison, N. S.; Etlicher, B.; Attelan, S.; Rouillé, C.; Chuvatin, A. S.; Aliaga, R.

    1994-03-01

    We are investigating the effects of an axial magnetic field to stabilize an aluminum vapor z-pinch. An aluminum plasma jet is created from an exploding foil in a DC magnetic field (Bz0 ≤ 300 G). The applied field is small compared to the azimuthal field, Bz0 ≫ Bϑ, and is intended to reduce the growth of instabilities during the compression phase. The pinch is driven by a 2 Ω, 0.1 TW generator (250 kA in 80 ns). Additionally, a micron sized wire may be placed on the pinch axis leading to the plasma-on-wire (POW) configuration. Qualitatively, increasing the axial magnetic field improves the pinch with the m=1 instabilities becoming negligible for fields higher than 150 G. We find that the externally applied fields can enhance x-ray production up to a critical field. Above this critical field x-ray emission decreases even though the pulse length of the radiation may still be increasing. As the applied field increases, the period of x-ray emission increases with the harder spectrum affected the least. The x-ray yield peaks for the POW and Al jet alone configurations at 150 G and 50 G respectively. Diagnostics include filtered PIN x-ray diodes, time-resolved schlieren photography, and time-integrated multiple filtered pinholes. We will present the results comparing the POW and aluminum jet configurations described above.

  20. Instability heating of solid-fiber Z pinches

    SciTech Connect

    Riley, R.A. Jr.

    1994-02-01

    The Los Alamos High Density Z Pinch-II (HDZP-II) facility is used to study the dynamics of z-pinch plasmas generated from solid fibers of deuterated polyethylene CD{sub 2} with a range in radii of 3--60 {mu}m. HDZP-II is a pulsed-power generator that delivers a current that rises to 700 kA in 100 ns through an inductive load. A multiframe circular schlieren records the evolution of the shape and size of the plasma on seven images taken at 10-ns intervals. These circular-schlieren images show very strong m=0 instability at the onset of current and a rapid radial expansion of the plasma. No higher-order instabilities are observed. An interferometer is used to infer the electron density and electron line density, giving a measure of the fraction of plasma contained within the outline of the circular-schlieren image at one time during the multiframe sequence. A three-channel x-ray crystal-reflection spectrometer provides the time-resolved, spatially-averaged electron temperature. The magnitude of the x-ray emission at these energies also gives qualitative information about the electron temperature and density at late times. A lower bound on the ion temperature is inferred from the particle pressure needed to balance the magnetic field pressure. The ion temperature rose above that of the electrons, strongly suggesting an additional heating term that puts energy directly into the ions. An ion heating term is proposed to explain the observed rapid radial expansion and elevated ion temperatures. This heating term is based on the assumption that the observed m=0 instabilities reconnect, enclosing magnetic flux which degenerates into turbulence in the plasma. A 0-D simulation is developed to investigate the relevance of different physical models to the data presented.

  1. Cu spectroscopy from a z-pinch plasma

    NASA Astrophysics Data System (ADS)

    Dasgupta, Arati; Clark, Robert W.; Ouart, Nicholas D.; Giuliani, John L.

    2014-11-01

    Recent improvements in diagnostic techniques at the Sandia Laboratories Z accelerator have facilitated the production of very detailed x-ray spectral data in the range of 1-20 keV. The high energy density plasma produced in a z-pinch is inherently in non-local thermodynamic equilibrium (NLTE). We therefore employ a NLTE collisional equilibrium model in a 1D radiation-magnetohydrodynamics code to simulate the dynamics of the pinch and to generate synthetic emission spectra. We will discuss the effects on radiation spectra and the yields of using simplifying assumptions in the atomic model and/or the radiation transport. X-ray emission from moderately high atomic number plasmas such as Fe and Cu wire array implosions often include substantial 2p-1s K-α radiation. In a z-pinch plasma, K-shell vacancies can be produced by e-beams, hot electrons at the tail of a Maxwellian and also by photopumping from energetic photons emitted near the pinch axis. In the Z-1975 Cu wire implosion, K-α lines from various ionization stages of Cu as well as from minor constituents including Ni, Fe and Cr are observed. We have calculated K-α production within a full simulation of a Cu implosion, including contributions from energetic electrons and photons. Photo-pumped K-α emission can be distinguished from that produced by e-beams; K-shell vacancies will be produced near the axis for a beam, and near the outer edge of the plasma for energetic photons. Spectroscopic modeling of these K-α lines as well as K- and L-shell emission from valence electrons can provide quantitative diagnostics of plasma parameters. This methodology can also be used to investigate K-α emission from other laboratory experiments such as EBIT and astrophysical plasmas.

  2. Z-Pinch Wire-Electrode Contact Resistance Studies Using Weighted and Soft Metal Gasket Contacts*

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

    The contact made between z-pinch wires and electrodes has a significant effect on both the energy deposited in the wires and the uniformity of the expansion profile of the wires. We have shown that using soft metal gaskets can improve wire-electrode contact significantly over typical weighted contacts. Images of wire expansion profile and wire plasma emission will be presented for single and double wire shots on a 16 kA, 100 kV 4-stage Marx bank with 150 ns risetime. Bench resistance measurements for aluminum, stainless steel, and tungsten wires with diameters ranging from 7.5 um to 30 um will be presented. These measurements utilized both soft metal gasket contacts (gaskets include: indium, silver, aluminum, tin, and lead) and double-ended wire weight contacts (weights ranged from 0.4 g to 1.9 g). *This research was supported by U. S. DoE through Sandia National Laboratories award document numbers 240985, 768225, 790791 and 805234 to the University of Michigan. MRG supported by NNSA Fellowship and JCZ supported by NPSC Fellowship sponsored by Sandia National Labs.

  3. 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

  4. Radiative properties of Z-pinch and laser produced plasmas from mid-atomic-number materials

    NASA Astrophysics Data System (ADS)

    Ouart, Nicholas D.

    The investigation of Z-pinches on university-scale pulsed power generators allows for the study of plasmas with a broad range of temperatures, densities, and sizes in cost effective experiments. In particular, X-pinches produce the hottest and densest plasma and are very suitable for x-ray radiation studies. The planar wire array has shown to be a powerful radiation source on the 1 MA Zebra generator at UNR. The radiative and implosion dynamics from such loads with mid-atomic-number materials were not studied previously in detail and are a topic of this dissertation. Specifically, the radiative and implosion characteristics of Z-pinch and X-pinch plasmas with mid-atomic-number materials (iron, nickel, copper, and zinc) will be discussed. The theoretical tool used to accomplish this is non-LTE kinetic modeling. This tool is not limited to Z-pinches, but can be applied to any plasma radiation source like laser produced plasmas which will be demonstrated. In addition, since the radiative characteristics of wire arrays are connected with the implosion characteristics, another theoretical tool, the Wire Ablation Dynamics Model was used in this dissertation to understand the ablation and implosion dynamics of wire arrays. The experiments were analyzed from two university-scale pulsed power machines: the 1 MA Zebra and COBRA generators. The research completed in this dissertation emphasizes the unique capabilities and usefulness of spectroscopy, particularly time-gated x-ray spectroscopy. For example, modeling of time-gated L-shell spectra captured from the precursor column of low-wire-number copper cylindrical wire arrays reveals electron temperatures ˜400 eV, which is significantly higher than any previous precursor measurements. From the analysis of experiments on COBRA, total energy was higher for the implosion of a compact cylindrical wire array made with alternating brass and aluminum wires than a uniform wire array made with just brass or aluminum. Comparison of L

  5. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

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

    SciTech Connect

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

    2010-03-15

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

  8. Recyclable Transmission Line (RTL) Concept for Z-Pinch IFE*

    NASA Astrophysics Data System (ADS)

    Olson, C. L.; Slutz, S. A.; Rochau, G. E.; Morrow, C. W.; Kammer, D. C.; Fatenejad, M.; El-Guebaly, L. A.; de Groot, J. S.; Peterson, P. F.

    2003-10-01

    The Recyclable Transmission Line (RTL) concept for IFE uses a recyclable material for the magnetically-insulated transmission line that connects the pulsed power accelerator to the z-pinch fusion target. The RTL may be made of frozen coolant (e.g., Flibe) or a material that is easily separable from the coolant (e.g., low activation ferritic steel). Initial experiments on Saturn at the 10 MA level have already shown excellent electrical turn-on for several candidate RTL materials, and demonstrated high electrical conductivities for thin low-mass RTLs. The present RTL baseline is a 50 kg ferritic steel RTL operating in a 10-20 Torr background chamber pressure. Initial results of investigations are presented on the RTL structural strength (buckling analysis); post-shot RTL formation of schrapnel/plasma; vacuum and electrical RTL connections to the power feed; post-shot effects up the RTL (EMP, schrapnel, etc.); activation and waste stream analysis; study of mechanical properties of foam Flibe; handling of sheer mass of RTLs (one-day storage supply, etc.); and RTL manufacturing and recycling system design.

  9. Polytropic scaling of a flow Z-pinch

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  10. Viscous Heating At Stagnation In Z-Pinches

    SciTech Connect

    Haines, M. G.

    2009-01-21

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

  11. Electromagnetic Wave Propagation Through the ZR 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.; Struve, K.; Corcoran, P. A.; Whitney, B.

    2009-01-01

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

  12. Cylindrical Liner Z-pinch Experiments on the MAGPIE Generator

    NASA Astrophysics Data System (ADS)

    Burdiak, Guy; Lebedev, Sergey V.; Harvey-Thompson, Adam J.; Swadling, George F.; Suzuki-Vidal, Francisco; Skidmore, Jonathan; Suttle, Lee; Khoory, Essa; Pickworth, Louisa; de Grouchy, Philip; Hall, Gareth N.; Bland, Simon N.; Weinwurm, Marcus; Chittenden, Jeremy P.

    2012-10-01

    Experimental data from gas-filled cylindrical liner z-pinch experiments is presented. The MAGPIE current (1.4 MA, 240 ns) is applied to a thin walled (80um) Al tube with a static gas-fill inside. The system is diagnosed axially using interferometry, optical streak photography and optical spectroscopy. We observe a series of cylindrically converging shock waves driven into the gas-fill from the inside liner surface. No bulk motion of the liner occurs. The timing of the shocks and their trajectories provide information on the shock launching mechanisms. This in turn allows a study of the response of the liner to the current pulse. Shock wave timing is compared to measurements of the liner resistance and optical images of the liner's outside surface. The system provides a useful, essentially 1D problem for testing MagLIF relevant MHD codes, particularly with regards to EOS, strength and resistivity models. This work may also be relevant to the study of shocks in astrophysical plasmas. The shocks launched into the gas radiatiate strongly; spatially resolved optical spectroscopy data and radial electron density profiles from interferometry images provide evidence for a radiative precursor ahead of the first shock. Instabilities are seen to develop in the downstream regions.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  14. Diagnostics for Z-pinch implosion experiments on PTS

    SciTech Connect

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

    2014-12-15

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

  15. Analytic model for the dynamic Z-pinch

    SciTech Connect

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

    2015-06-15

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

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

    SciTech Connect

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

    2009-01-21

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

  17. Electromagnetic wave propagation through the ZR Z-pinch accelerator.

    SciTech Connect

    Welch, Dale Robert; Clark, R. E.; Rose, David Vincent; Madrid, Elizabeth Ann; Corcoran, P. A.; Struve, Kenneth William; Stygar, William A.; Miller, C. L.; Whitney, B.

    2008-08-01

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

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

    SciTech Connect

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

    2014-11-15

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

  19. Neon Photoionization Experiments Driven By Z-Pinch Radiation

    NASA Astrophysics Data System (ADS)

    Bailey, J. E.; Cohen, D.; Chandler, G. A.; Cuneo, M. E.; Nash, T. J.; Stygar, W. A.; MacFarlane, J. J.; Jobe, D.; Lake, P.; Nielson, D.; Smelser, R.; Foord, M. E.; Heeter, R. F.; Liedahl, D. A.

    2000-10-01

    Present-day Z-pinch experiments generate 2 x 1021 erg/s, 5 nsec duration x-ray bursts that provide new possibilities to study radiation-heated matter. We are using this source to investigate plasmas in which photoionization dominates collisional ionization. Spectroscopic measurements of such plasmas can serve to benchmark photoionized-plasma atomic physics models that will be used to interpret data from the new generation of x-ray satellite spectrographs. This should be useful for understanding accretion-powered objects such as X-ray binaries and active galactic nuclei. These objects are frequently observed, but the interpretation of their spectra is difficult: state-of-the-art models for photoionized plasmas do not always agree on the expected ionization distribution. Our experiments use a 1-cm-scale gas cell to expose various gases to an x-ray flux of approximately 3 x 1019 erg/s/cm2. Thin mylar (1.5 micron) windows allow the radiation to flow into the cell. The ionization is monitored using emission and absorption spectroscopy. In initial experiments we acquired an absorption spectrum from Li- and He-like Ne. Analysis of the measurements and comparison with computer simulations are in progress. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000

  20. 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).

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

    SciTech Connect

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

    2014-12-15

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

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

    SciTech Connect

    Hurricane, O

    2003-10-16

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

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

    SciTech Connect

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

    2009-01-21

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

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

    SciTech Connect

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

    1996-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

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

  6. 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

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    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 μm to obtain areal density measurements of the W plasma from the wire-array. Images had subnanosecond temporal resolution and about 10 μm spatial resolution.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

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

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

    SciTech Connect

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

    2006-12-04

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

  13. The Imaging of Z-Pinches Using X-Pinch Backlighting

    SciTech Connect

    Douglass, J.D.; Greenly, J.B.; Hammer, D.A.; McBride, R.D.; Pikuz, S.A.; Shelkovenko, T.A.

    2006-01-05

    Imaging using X-pinch backlighters has been implemented on the COBRA accelerator at Cornell University to study the early stages of wire-array Z-pinches. Two of four return-current posts in the wire-array load region are replaced by X pinches so that two images of one wire in an eight-wire z-pinch are obtained from different angles and at different times. High resolution images have been obtained that show the evolution of wire structure and instabilities. X-pinch wire diameter and other parameters were varied in order to shift the timing of the X pinches relative to the start of the z-pinch current pulse. It was found that XPBL wire diameter (mass per unit length) has the strongest influence on radiation timing.

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

    NASA Astrophysics Data System (ADS)

    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.

    2008-03-01

    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.

  15. Recent Improvements to MACH2 and MACH3 For Fast Z-Pinch Modeling

    NASA Astrophysics Data System (ADS)

    Frese, Sherry D.; Frese, Michael H.

    2002-12-01

    Many recent changes in MACH2 have improved the code's accuracy and speed in Z-pinch simulations. New code diagnostics monitoring energy are also useful in running the code efficiently. The changes to MACH3 are less numerous, though they are more sweeping: MACH3's grid is now truly three-dimensional and composed of a multiblock structure of arbitrary hexahedral zones; its difference equations have been upgraded to that new mesh. These new capabilities are currently being applied to wire-array Z-pinch problems.

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

    SciTech Connect

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

    2009-01-21

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

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

    NASA Astrophysics Data System (ADS)

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

    1998-08-01

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

  18. 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.

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

    SciTech Connect

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

    2008-02-15

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

  20. Low mass recyclable transmission lines for Z-pinch driven inertial fusion

    NASA Astrophysics Data System (ADS)

    Slutz, S. A.; Olson, C. L.; Peterson, Per

    2003-02-01

    Recyclable transmission lines (RTLs) are being studied as a means to repetitively drive Z pinches. Minimizing the mass of the RTL should also minimize the reprocessing costs. Low mass RTLs could also help reduce the cost of a single shot facility such as the proposed X-1 accelerator and make Z-pinch driven nuclear space propulsion feasible. Calculations are presented to determine the minimum electrode mass to provide sufficient inertia against the magnetic pressure produced by the large currents needed to drive the Z pinches. The results indicate an electrode thickness which is much smaller than the initial resistive skin depth. This suggests that the minimum electrode thickness may be not be solely determined by inertial effects, but also by the ability of the electrode to efficiently carry the current. A series of experiments have been performed to determine the ability of the electrodes to carry current as a function of the electrode thickness. The results indicate that electrodes much thinner than the initial resistive skin depth can efficiently carry large currents presumably due to the formation of a highly conducting plasma. This result implies that a transmission line with only a few tens of kilograms of material can carry the large Z-pinch currents needed for inertial fusion.

  1. High-energy electron acceleration in the gas-puff Z-pinch plasma

    SciTech Connect

    Takasugi, Keiichi; Miyazaki, Takanori; Nishio, Mineyuki

    2014-12-15

    The characteristics of hard x-ray generation were examined in the gas-puff z-pinch experiment. The experiment on reversing the voltage was conducted. In both of the positive and negative discharges, the x-ray was generated only from the anode surface, so it was considered that the electrons were accelerated by the induced electromagnetic force at the pinch time.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

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

    SciTech Connect

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

    2009-01-21

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

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

    SciTech Connect

    Lindemuth, Irvin R.

    2009-01-21

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

  5. 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

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

    SciTech Connect

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

    2009-01-21

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

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

    NASA Astrophysics Data System (ADS)

    Tarditi, Alfonso G.

    2015-11-01

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

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

    SciTech Connect

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

    2014-12-15

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

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

    SciTech Connect

    Ponce-Marquez, David

    2002-07-09

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    SciTech Connect

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

    2015-11-15

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

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

    PubMed

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

    2015-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  14. Examination of resistivity issues in solid liner z-pinches

    SciTech Connect

    Atchison, W.L.; Faehl, R.J.; Reinovsky, R.E.

    1999-07-01

    Experiments being conducted at the Los Alamos National lab Pegasus facility are examining driving an aluminum liner with a pulsed magnetic field. The Pegasus facility provides a current of 5 to 8 Mega-amps to compress a cylindrical liner. Liners of various size and thickness are used, depending on the specific experimental objectives. In several of these experiments, a B-dot probe has been used to measure the field diffused through the liners. This data has been compared to predictions of field penetrations using numerical simulations. These predictions were made with a 2D Eulerian and a 1D Lagrangian MHD code. The simulations were made with a wide variety of resistivity models including both SESAME tabular values and analytic models. the results of these comparisons show that the behavior of aluminum in the region from a few tenths of a eV to 1eV and densities from about .2 to 3.0 g/cc is not reproduced well. While this is understandable based on the back of conclusive data in the region, these experiments confirm the in-applicability of extrapolating existing models into this region where phase changes are drastically changing the behavior.

  15. 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.

  16. Spectroscopy of Z-pinch plasmas: how atomic and plasma physics merge and unfold new applications

    NASA Astrophysics Data System (ADS)

    Safronova, Alla

    2012-06-01

    Recent advances in theoretical and experimental work on plasma spectroscopy of Z-pinches are presented. We have shown that the University-scale Z-pinch generators are able to produce plasmas within a broad range of temperatures, densities, opacity, and radiative properties depending on the type, geometry, size, and mass of wire array loads and wire material. The full x-ray and EUV diagnostic set for detailed spatial and temporal monitoring of such a plasma together with relativistic atomic and non-LTE kinetic codes create a very useful and productive environment for the study of atomic and plasma spectroscopy features and development of their applications. A variety of examples of K-shell low-Z (such as Mg and Al), L-shell mid-Z (such as Ni, Cu, and Ag), and M- and L-shell high-Z (W) will be considered and their specific features and applications to fusion and astrophysics will be highlighted.

  17. Advances in experimental spectroscopy of Z-pinch plasmas and applications

    NASA Astrophysics Data System (ADS)

    Kantsyrev, V. L.; Safronova, A. S.; Safronova, U. I.; Shrestha, I.; Weller, M. E.; Osborne, G. C.; Shlyaptseva, V. V.; Wilcox, P. G.; Stafford, A.

    2012-06-01

    Recent advances in experimental work on plasma spectroscopy of Z-pinches are presented. The results of experiments on the 1.7 MA Z-pinch Zebra generator at UNR with wire arrays of various configurations and X-pinches are overviewed. A full x-ray and EUV diagnostic set for detailed spatial and temporal monitoring of such plasmas together with theoretical support from relativistic atomic structure and non-LTE kinetic codes used in the analysis are discussed. The use of a variety of wire materials in a broad range from Al to W provided an excellent opportunity to observe and study specific atomic and plasma spectroscopy features. In addition, the applications of such features to fusion and astrophysics will be considered.

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

    SciTech Connect

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

    1996-05-14

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

  19. Progress in Z-pinch research driven by the mega-ampere device SPEED2

    SciTech Connect

    Pavez, Cristian; Soto, Leopoldo; Moreno, Jose; Tarifeno, Ariel; Sylvester, Gustavo

    2008-04-07

    Several pinch configurations have being studied at the Chilean Nuclear Energy Commission using the SPEED2 generator: plasma focus, gas embedded z-pinch and wire arrays. SPEED2 is a generator based on Marx technology (4.1 {mu}F equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt{approx}10{sup 13} A/s). Currently the device is being operated at 70kJ stored energy producing a peak current of 2.4 MA in short circuit. In this work results related to studies in gas embedded z-pinch in deuterium and studies in wire arrays are presented.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

    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 Ω (depending on wire weight mass) to 1-10 Ω with soft metal gaskets. Single wire experiments (13 μm 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.

  2. Sheath broadening in imploding z-pinches due to large-bandwidth Rayleigh-Taylor instability

    SciTech Connect

    Hammer, J.H.; Eddleman, J.L.; Tabak, M.; Toor, A.; Zimmerman, G.B.; De Groot, J.S.

    1996-06-04

    The magnetic Rayleigh-Taylor (RT) instability has been predicted and observed to cause breakup of the plasma sheath in imploding Z-pinches. In this work we show that for the type of density profile encountered in strongly radiating pinches, instability at very short wavelengths grows to the non-linear stage and seeds progressively longer wavelengths. The result is a self-similar broadening of the sheath as found for mix layers in fluid RT unstable systems.

  3. Target design for high fusion yield with the double Z-pinch-driven hohlraum.

    NASA Astrophysics Data System (ADS)

    Vesey, Roger

    2006-10-01

    A key demonstration on the path to inertial fusion energy is the achievement of high fusion yield (hundreds of MJ) and high target gain. An indirect-drive high-yield inertial confinement fusion (ICF) target involving two z-pinch x-ray sources heating a central secondary hohlraum is described by Hammer, Tabak, Wilks, et al. [Phys. Plasmas 6, 2129 (1999)]. In subsequent research at Sandia National Laboratories, we have developed theoretical/computational models and performed an extensive series of validation experiments to study hohlraum energetics, capsule coupling, and capsule implosion symmetry. We are using these models to design a 0.5 GJ yield z-pinch-driven ICF target that incorporates the latest experience in capsule design, hohlraum symmetry control, and x-ray production by z-pinches. An x-ray energy output of 8-9 MJ per pinch, suitably pulse-shaped, is sufficient for this concept to drive 0.3-0.5 GJ capsules. Integrated 2D hohlraum/capsule LASNEX radiation-hydrodynamics simulations have demonstrated adequate hohlraum coupling, radiation symmetry control, and the successful implosion, ignition and burn of a 0.5 GJ ICF capsule. An important new feature of this target design is mode-selective symmetry control: the use of burnthrough shields offset from the capsule that selectively tune certain low-order asymmetry modes (P2, P4) without significantly perturbing higher-order modes. This talk will describe the capsule and hohlraum design that have produced 0.5 GJ yields in 2D simulations, as well as provide a preliminary design of the z-pinch load and accelerator requirements necessary to drive the system. In collaboration with M. C. Herrmann, R. W. Lemke, G. R. Bennett, R. B. Campbell, P. J. Christenson, M. E. Cuneo, M. P. Desjarlais, T. A. Mehlhorn, J. L. Porter, D. B. Sinars, S. A. Slutz, W. A. Stygar, E. P. Yu, and J. H. Hammer (LLNL).

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  5. Plasma Density Measurements within Tungsten Wire-Array Z-Pinches on the COBRA Accelerator

    NASA Astrophysics Data System (ADS)

    Douglass, Jon; McBride, Ryan; Bell, Kate; Knapp, Patrick; Greenly, John; Pikuz, Sergei; Shelkovenko, Tanya; Hammer, David

    2007-11-01

    The COBRA pulsed-power generator, with a nominal peak current of 1.1 MA and a minimum zero-to-peak rise-time of about 100ns, is being used to study the early phases of wire-array z-pinch development with a variety of diagnostics. Here we present the results of applying point-projection x-ray radiography to make accurate, high-resolution spatial and temporal measurements of the plasma density distributions in tungsten (W) wire-array z-pinch implosions. Density measurements are quantified by comparing x-ray transmission recorded on photographic films to transmission through W calibration steps of known thicknesses. Plasma density distributions as a function of time are presented for the coronal (10^18-10^20/cm^3), ablation (<10^18/cm^3) and on-axis (<10^19/cm^3) plasmas during the pre-stagnation phases of z-pinch dynamics (70-170 ns after the start of the current pulse). With this data set the time dependence of ablation velocity and corresponding mass ablation rate are addressed.

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

    NASA Astrophysics Data System (ADS)

    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 , Phys. PlasmasPHPAEN1070-664X10.1063/1.2896577 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.

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

    SciTech Connect

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

    2015-09-15

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

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

    SciTech Connect

    Ivanov, V. V.; Mancini, R. C.; Papp, D.; Hakel, P.; Durmaz, T.; Florido, R.

    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.

  9. Radiative signatures of Z-pinch plasmas at UNR: from X-pinches to wire arrays

    NASA Astrophysics Data System (ADS)

    Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Safronova, U. I.; Shlyaptseva, V. V.; Shrestha, I.; Osborne, G. C.; Weller, M. E.; Stafford, A.; Lorance, M.; Chuvatin, A. S.

    2014-08-01

    University-scale Z-pinch generators are able to produce High Energy Density (HED) plasmas in a broad range of plasma parameters under well-controlled and monitored experimental conditions suitable for radiation studies. The implosion of X-pinch and wire array loads at a 1 MA generator yields short (1-20 nsec) x-ray bursts from one or several bright plasma spots near the wire cross point (for X-pinches) or along and near Z-pinch axis (for wire arrays). Such X- and Z-pinch HED plasma with scales from a few µm to several mm in size emits radiation in a broad range of energies from 10 eV to 0.5 MeV and is subject of our studies during the last ten years. In particular, the substantial number of experiments with very different wire loads was performed on the 1 MA Zebra generator and analyzed: X-pinch, cylindrical, nested, and various types of the novel load, Planar Wire Arrays (PWA). Also, the experiments at an enhanced current of 1.5-1.7 MA on Zebra using Load Current Multiplier (LCM) were performed. This paper highlights radiative signatures of X-pinches and Single and Double PWAs which are illustrated using the new results with combined wire loads from two different materials.

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

    SciTech Connect

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

    2013-11-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

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

    SciTech Connect

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

    2015-07-15

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

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

    SciTech Connect

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

    2011-10-15

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

  14. Overview and Recent Results from the ZaP Flow Z-Pinch

    NASA Astrophysics Data System (ADS)

    Shumlak, U.

    2005-10-01

    The ZaP Flow Z-Pinch Experiment at the University of Washington investigates sheared flow stabilization in an otherwise unstable configuration. An axially flowing Z-pinch is generated with a coaxial accelerator coupled to a pinch assembly chamber. Magnetic probes measure the fluctuation levels of the azimuthal modes m = 1, 2, and 3. The plasma is magnetically confined for an extended quiescent period where the mode activity is significantly reduced. Multichord Doppler shift measurements of impurity lines show a large, sheared flow during the quiescent period and low shear profiles during periods of high mode activity. The plasma has a sheared axial flow that exceeds the theoretical threshold for stability during the quiescent period and is lower than the threshold during periods of high mode activity. The Z-pinch plasmas are globally stable for approximately 2000 growth times. The end of the quiescent period corresponds to a drop in plasma density and a decrease in plasma acceleration. Recent experimental results suggest a means to extend the experiment to quasi steady state operation.

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

    SciTech Connect

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

    1997-12-01

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

  16. Study of implosion dynamics of Z-pinch dynamic hohlraum on the Angara-5-1 facility

    NASA Astrophysics Data System (ADS)

    Zhang, Faqiang; Xu, Rongkun; Xu, Zeping; Yang, Jianlun; Li, Zhenghong; Xia, Guangxin; Ning, Jiamin; Li, Linbo; Chen, Dingyang; Chen, Jinchuan

    2015-02-01

    The Z-pinch dynamic hohlraum (ZPDH) is one of high-power X-ray sources that has been used in a variety of high energy-density experiments including inertial confinement fusion (ICF) studies. Dynamic hohlraums driven by a 12-mm and a 18-mm-diameter single tungsten wire arrays embedded with a C16H20O6 foam, respectively, exhibit no visible differences in radiation from the axial exit, although the radial radiation is a little higher in a large array. The analysis of the images suggests that the implosion of a large array is quasi-continuous and has a faster imploding velocity, indicating that the large array is matched to the embedded foam and, oppositely, the small array is mismatched. The analysis also shows that the Rayleigh-Taylor instability develops much harder in implosions of a large array, and this leads to a lower hohlraum temperature. The conclusion was drawn that, for the purpose of enhancing the hohlraum temperature, increasing the conversion efficiency of kinetic energy into thermal energy is more important than increasing the kinetic energy from wire plasma.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    SciTech Connect

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

    2015-02-15

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

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

    SciTech Connect

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

    2013-01-15

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

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

    NASA Astrophysics Data System (ADS)

    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 < λ < 15 nm) present during harsh wire array z-pinch implosions. The spectrometer utilizes a 25 μm 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.

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

    SciTech Connect

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

    2007-04-04

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

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

    SciTech Connect

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

    2011-09-15

    This recently developed diagnostic was designed to allow for time-gated spectroscopic study of the EUV radiation (4 nm < {lambda} < 15 nm) present during harsh wire array z-pinch implosions. The spectrometer utilizes a 25 {mu}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 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.

  3. 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

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

    SciTech Connect

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

    2008-10-15

    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{sub 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.

  5. Demonstration of Radiation Symmetry Control for Inertial Confinement Fusion in Double Z-Pinch Hohlraums

    NASA Astrophysics Data System (ADS)

    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.

    2003-01-01

    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.

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

    SciTech Connect

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

    1991-03-15

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

  7. Z-Pinch Generated X-Rays Demonstrate Indirect-Drive ICF Potential

    SciTech Connect

    Bowers, R.L.; Chandler, G.A.; Derzon, M.S.; Hebron, D.E.; Leeper, R.J.; Matzen, M.K.; Mock, R.C.; Nash, T.J.; Olson, R.E.; Peterson, D.L.; Ruggles, L.E.; Sanford, T.W.L.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.

    1999-06-16

    Hohlraums (measuring 6-mm in diameter by 7-mm in height) have been heated by x-rays from a z-pinch. Over measured x-ray input powers P of 0.7 to 13 TW, the hohlraum radiation temperature T increases from {approximately}55 to {approximately}130 eV, and is in agreement with the Planckian relation P-T{sup 4}. The results suggest that indirect-drive ICF studies involving NIF relevant pulse shapes and <2-mm diameter capsules can he studied using this arrangement.

  8. 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.

  9. Experimental Study of Implosion Dynamics of Multi-Shell Z-Pinches at Microsecond Implosion Times

    NASA Astrophysics Data System (ADS)

    Shishlov, Alexander V.; Chaikovsky, Stanislav A.; Fedunin, Anatoly V.; Fursov, Fedor I.; Kokshenev, Vladimir A.; Kurmaev, Nikolai E.; Labetsky, Aleksey Yu.; Oreshkin, Vladimir I.; Rousskikh, Alexander G.; Zhidkova, Natalia A.

    2006-01-01

    A set of experiments has been conducted on the GIT-12 generator (4.7 MA, 1.7 μs) operating at microsecond mode. The experiments were carried out with multi-shell gas puffs. Dynamics of current-carrying plasma was registered by a set of B-dots monitors placed at different radii inside a multi-shell gas puff. The experimental data obtained with the help of B-dots monitors are compared with 0D snow-plow simulations of implosion dynamics and discussed taking into consideration the data from other Z-pinch diagnostics.

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

    SciTech Connect

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

    2004-10-01

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

  11. Mapping return currents in laser-generated Z-pinch plasmas using proton deflectometry

    SciTech Connect

    Manuel, M. J.-E.; Sinenian, N.; Seguin, F. H.; Li, C. K.; Frenje, J. A.; Rinderknecht, H. G.; Casey, D. T.; Zylstra, A. B.; Petrasso, R. D.; Beg, F. N.

    2012-05-14

    Dynamic return currents and electromagnetic field structure in laser-generated Z-pinch plasmas have been measured using proton deflectometry. Experiments were modeled to accurately interpret deflections observed in proton radiographs. Current flow is shown to begin on axis and migrate outwards with the expanding coronal plasma. Magnetic field strengths of {approx}1 T are generated by currents that increase from {approx}2 kA to {approx}7 kA over the course of the laser pulse. Proton deflectometry has been demonstrated to be a practical alternative to other magnetic field diagnostics for these types of plasmas.

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

    NASA Astrophysics Data System (ADS)

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

    2009-01-01

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

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

    SciTech Connect

    1995-12-01

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

  14. Z pinches as intense x-ray sources for inertial confinement fusion applications

    SciTech Connect

    Matzen, M.K.

    1997-05-01

    Fast z-pinch implosions can convert more than 10% of the stored electrical energy in a pulsed-power accelerator into x-rays. On the Saturn pulsed-power accelerator at Sandia National Laboratories, currents of 6 to 8 MA with a risetime of less than 50 ns have been used to drive cylindrically-symmetric arrays of wires, producing x-ray energies greater than 400 kJ with x-ray pulsewidths less than 5 ns and peak x-ray powers of 75 {+-} 10 TW. Using similar loads, PBFA Z has produced > 1.5 MJ and > 150 TW of x-rays in the first four months of operation in the z-pinch mode. These x-ray energies and powers are records for laboratory x-ray production. The x-ray output can be thermalized into a near-Planckian x-ray source by containing it within a cylindrical radiation case (a hohlraum). These energetic, intense, large volume, long-lived hohlraum x-ray sources have recently been used for ICF-relevant ablator physics experiments and offer the potential for performing many new basic physics and fusion-relevant experiments.

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

    NASA Astrophysics Data System (ADS)

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

    1996-04-01

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

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  18. Effects of an axial magnetic field on Z-pinch plasmas for extreme ultraviolet sources

    SciTech Connect

    Katsuki, Sunao; Kimura, Akihiro; Kondo, Yoshihiro; Horita, Hiroyuki; Namihira, Takao; Sakugawa, Takashi; Akiyama, Hidenori

    2006-01-01

    This paper describes the effect of an axial magnetic field (B{sub z}) on plasma pinch dynamics and on the extreme ultraviolet (EUV) emission property of a compact Z-pinch device for EUV sources. The Z-pinch xenon plasma was driven by a pulse current with an amplitude of 27 kA and duration of 150 ns in an alumina tube with a diameter of 5 mm. A quasistatic magnetic field of up to 360 G is applied to the plasma. The EUV emission was evaluated for spectra, spatial distribution of the emission, and light energy at 13.5 nm with 2% bandwidth. A time-resolved interferogram provides the electron line density and pinch dynamics of the plasma. When a magnetic field of 160 G was applied to the plasma, the emission energy was approximately double that without the magnetic field. The spectroscopic measurement shows that the EUV spectrum drastically varies with magnetic-field strength. The time-resolved interferogram indicates that the axial magnetic field contributes by making the plasma compression smooth and by sustaining certain plasma conditions longer. From these experimental results, it was concluded that applying an axial magnetic field can be an effective method to improve EUV emission.

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

    SciTech Connect

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

    2009-01-21

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

  20. 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.

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

    NASA Astrophysics Data System (ADS)

    Bures, Brian L.; Krishnan, Mahadevan

    2012-11-01

    The DD neutron yield (Yn) from z-pinches, either dense plasma foci or fast radial pinches, has been fitted for decades to the scaling model Yn ˜ α(Imax)δ, where α is a numerical scaling coefficient, Imax the peak current, and 3 < δ < 5. The data from 12 000 pulses analyzed from eight different z-pinches presented in this paper show that Yn varies by as much as ±15 000% about the best fit value of the conventional scaling model with δ = 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.

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

    SciTech Connect

    Bures, Brian L.; Krishnan, Mahadevan

    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.

  3. Investigation of Heating Mechanisms in the ZaP Flow Z-Pinch

    NASA Astrophysics Data System (ADS)

    Knecht, S. D.; Shumlak, U.; Nelson, B. A.; Golingo, R. P.

    2010-11-01

    The ZaP Flow Z-Pinch at the University of Washington is a basic plasma physics experiment that investigates stabilizing a Z-pinch with a radially-varying axial flow, dvz/dr. ZaP consists of a coaxial accelerator region coupled to a pinch assembly region. It is hypothesized that the primary means of heating in ZaP is through adiabatic compression during pinch formation. The 10 cm inner electrode of ZaP is replaced with a 16 cm inner electrode to investigate this hypothesis. A four-chord HeNe interferometer is used to determine a pinch density profile as a function of time, and radial force balance and conservation of energy equations are used to determine temperature and magnetic field profiles. Temperature measurements are made with a 20-chord imaging spectrometer (Ti) and a Thomson-scattering system (Te) and compared to the calculated temperatures. The profiles are investigated for a range of accelerator densities and pinch currents for both electrode configurations. The possible effects of adiabatic compression, Ohmic heating and shock heating will be evaluated and reported.

  4. Overview and Recent Results from the ZaP Flow Z-Pinch

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; Nelson, B. A.; Adams, C. S.; Chahim, D. M.; den Hartog, D. J.; Golingo, R. P.; Knecht, S. D.; Oberto, R.; Sybouts, M.; Vogman, G.

    2007-11-01

    The ZaP Flow Z-Pinch investigates a magnetic confinement configuration that relies on sheared flow for stability in an otherwise unstable configuration. An axially flowing Z-pinch is generated with a coaxial accelerator coupled to a pinch assembly chamber. Magnetic probes measure fluctuation levels. Plasma is magnetically confined for an extended quiescent period where the mode activity is reduced. Doppler shift measurements of impurity lines show sub-Alfvenic, sheared flow during the quiescent period and low shear profiles during periods of high mode activity. The plasma has a sheared axial flow that exceeds the theoretical threshold for stability during the quiescent period and is lower than the threshold during periods of high mode activity. A holographic interferometer measures radially peaked density profiles during the quiescent period. Density profiles are analyzed to determine equilibrium profiles. Internal magnetic fields have been determined by measuring the Zeeman splitting of impurity emission. Measurements are consistent with a magnetically confined plasma. Plasma lifetime appears to be limited by neutral gas supply.

  5. Overview and Recent Results from the ZaP Flow Z-Pinch

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; Neslon, B. A.; Adams, C. S.; den Hartog, D. J.; Golingo, R. P.; Knecht, S. D.; Munson, K. A.; Newman, J.; Pasko, J.; Schmuland, D.; Sybouts, M.; Vogman, G.

    2006-10-01

    The ZaP Flow Z-Pinch Experiment at the University of Washington investigates a magnetic confinement configuration that relies on sheared flow for stability in an otherwise unstable configuration. An axially flowing Z-pinch is generated with a coaxial accelerator coupled to a pinch assembly chamber. Magnetic probes measure fluctuation levels. The plasma is magnetically confined for an extended quiescent period where the mode activity is reduced. Multichord Doppler shift measurements of impurity lines show a sub-Alfvenic, sheared flow during the quiescent period and low shear profiles during periods of high mode activity. The plasma has a sheared axial flow that exceeds the theoretical threshold for stability during the quiescent period and is lower than the threshold during periods of high mode activity. A holographic interferometer measures a radially peaked density profile during the quiescent period. Density profiles are analyzed to determine magnetic field and temperature profiles. Internal magnetic fields have been recently determined by measuring the Zeeman splitting of impurity carbon emission. The measurements are consistent with a magnetically confined pinch plasma. Recent experimental measurements will be presented. This work is supported by a grant from DOE.

  6. High-Z Pusher Experiments on the Cobra Triple Nozzle Gas-Puff Z-Pinch

    NASA Astrophysics Data System (ADS)

    de Grouchy, Philip; Qi, Niansheng; Kusse, Bruce; Seyler, Charles; Atoyan, Levon; Byvank, Tom; Cahill, Adam; Greenly, John; Hoyt, Cad; Pikuz, Sergei; Shelkovenko, Tania; Hammer, David

    2014-10-01

    For inertial confinement fusion application and as efficient hard x-ray sources, the imploding sheath of a gas-puff z-pinch or thin liner must be accelerated to the highest possible velocity before hydrodynamic instabilities significantly disrupt the implosion symmetry. Much recent work has focused on increasing implosion stability using radially structured mass-density profiles produced by multi-nozzle gas-puff valves. The introduction of a high-Z element such as xenon into the outer gas shells in such experiments can modify radiation output during the implosion phase as well as at stagnation. In these experiments xenon is introduced into the triple-nozzle gas valve fielded on the (1 MA, 200 ns) COBRA z-pinch machine at Cornell University. The xenon is introduced only in the outer shell, only in the inner shell or in both, to investigate the radiative effects on implosion hydrodynamics and x-ray yield. Results are compared to those obtained during pure argon implosions with the same mass-density profile. Sheath thicknesses and stability are recorded using laser interferometry (532 nm) and multi-frame imaging systems. The distribution of flow velocities and of high-Z material across the pinch is investigated using a (5 GW, 527 nm) Thomson scattering probe. Work supported by DOE Grant No. DE-NA0001836.

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

    SciTech Connect

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

    2014-12-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

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

    SciTech Connect

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

    2013-08-15

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

  10. Optical streak camera images of wire-array z-pinches on the 1-MA COBRA pulsed power generator

    NASA Astrophysics Data System (ADS)

    McBride, Ryan; Pikuz, Sergei; Blesener, Isaac; Zhao, Yu Tao; Greenly, John; Hammer, David; Kusse, Bruce

    2006-10-01

    Initial optical streak camera imaging experiments of wire array z-pinches on the 1 MA COBRA pulsed power generator are presented. The imaging system makes use of a Hamamatsu C7700 streak unit, which is coupled to a V7669-06 image intensifier with an MCP, and a C4742-98 CCD camera. A long focal length optical system is employed to relay the z-pinch produced light from the experiment chamber to the input slit of the streak camera -- a total transmission distance of approximately 14 m. The optical streak camera images produced, along with data from other supporting diagnostics, are presented for z-pinch implosions of various wire array geometries and materials.

  11. Ion debris characterization from a z-pinch extreme ultraviolet light source

    SciTech Connect

    Antonsen, Erik L.; Thompson, Keith C.; Hendricks, Matthew R.; Alman, Darren A.; Jurczyk, Brian E.; Ruzic, D.N.

    2006-03-15

    An XTREME Technologies XTS 13-35 extreme ultraviolet (EUV) light source creates a xenon z pinch that generates 13.5 nm light. Due to the near x-ray nature of light at this wavelength, extremely smooth metal mirrors for photon collection must be employed. These are exposed to the source debris. Dissolution of the z-pinch gas column results in high-energy ion and neutral release throughout the chamber that can have adverse effects on mirror surfaces. The XTREME commercial EUV emission diagnostic chamber was designed to maximize diagnostic access to the light and particulate emissions from the z pinch. The principal investigation is characterization of the debris field and the erosive effects on optics present. Light emission from the z pinch is followed by ejection of multiply charged ions and fast neutral particles that make up an erosive flux to chamber surfaces. Attenuation of this erosive flux to optical surfaces is attempted by inclusion of a debris mitigation tool consisting of foil traps and neutral buffer gas flow. Characterization of the z-pinch ejecta is performed with a spherical sector energy analyzer (ESA) that diagnoses fast ion species by energy-to-charge ratio using ion time-of-flight (ITOF) analysis. This is used to evaluate the debris tool's ability to divert direct fast ions from impact on optic surfaces. The ITOF-ESA is used to characterize both the energy and angular distribution of the direct fast ions. Xe{sup +} up to Xe{sup +4} ions have been characterized along with Ar{sup +} (the buffer gas used), W{sup +}, Mo{sup +}, Si{sup +}, Fe{sup +}, and Ni{sup +}. Energy spectra for these species from 0.5 up to 13 keV are defined at 20 deg. and 30 deg. from the pinch centerline in the chamber. Results show a drop in ion flux with angular increase. The dominant species is Xe{sup +} which peaks around 8 keV. Ion flux measured against buffer gas flow rate suggests that the direct fast ion population is significantly attenuated through increases in buffer

  12. 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

  13. Ion debris characterization from a z-pinch extreme ultraviolet light source

    NASA Astrophysics Data System (ADS)

    Antonsen, Erik L.; Thompson, Keith C.; Hendricks, Matthew R.; Alman, Darren A.; Jurczyk, Brian E.; Ruzic, D. N.

    2006-03-01

    An XTREME Technologies XTS 13-35 extreme ultraviolet (EUV) light source creates a xenon z pinch that generates 13.5 nm light. Due to the near x-ray nature of light at this wavelength, extremely smooth metal mirrors for photon collection must be employed. These are exposed to the source debris. Dissolution of the z-pinch gas column results in high-energy ion and neutral release throughout the chamber that can have adverse effects on mirror surfaces. The XTREME commercial EUV emission diagnostic chamber was designed to maximize diagnostic access to the light and particulate emissions from the z pinch. The principal investigation is characterization of the debris field and the erosive effects on optics present. Light emission from the z pinch is followed by ejection of multiply charged ions and fast neutral particles that make up an erosive flux to chamber surfaces. Attenuation of this erosive flux to optical surfaces is attempted by inclusion of a debris mitigation tool consisting of foil traps and neutral buffer gas flow. Characterization of the z-pinch ejecta is performed with a spherical sector energy analyzer (ESA) that diagnoses fast ion species by energy-to-charge ratio using ion time-of-flight (ITOF) analysis. This is used to evaluate the debris tool's ability to divert direct fast ions from impact on optic surfaces. The ITOF-ESA is used to characterize both the energy and angular distribution of the direct fast ions. Xe+ up to Xe+4 ions have been characterized along with Ar+ (the buffer gas used), W+, Mo+, Si+, Fe+, and Ni+. Energy spectra for these species from 0.5 up to 13 keV are defined at 20° and 30° from the pinch centerline in the chamber. Results show a drop in ion flux with angular increase. The dominant species is Xe+ which peaks around 8 keV. Ion flux measured against buffer gas flow rate suggests that the direct fast ion population is significantly attenuated through increases in buffer gas flow rate. This does not address momentum transfer from

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

    SciTech Connect

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

    2014-06-09

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

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

    SciTech Connect

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

    2009-01-15

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

  16. 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.

  17. Theoretical and Experimental Studies of Radiation from Z-Pinch Complex Wire Arrays and Applications

    NASA Astrophysics Data System (ADS)

    Weller, Michael Eugene

    In the research area of high energy density plasmas an ever increasing goal is searching for higher efficient radiators, particularly in z-pinch plasmas, and their applications. This goal is a major focus of this dissertation and implements both theoretical and experimental tools in the process. The theoretical tools involve the Wire Ablation Dynamics Model (WADM) to infer z-pinch implosion characteristics and various non-local thermodynamic equilibrium (LTE) kinetic models to understand the radiative properties of plasmas, including a new model for L-shell Ag. The experimental tools includes an advanced set of diagnostics, in particular a newly developed time-gated hard x-ray spectrometer to gain an understanding as to how these plasmas radiate in time, particularly in the 0.7 - 4.4 A range. The experiments predominately took place on the 1.7 MA Zebra generator at the Nevada Terawatt Facility (NTF) at the University of Nevada, Reno (UNR). Traditional nested cylindrical wire arrays with mixed materials (brass and Al, Mo and Al) were tested to understand how the inner and outer arrays implode and radiate. Novel planar wire arrays, which have been shown to be very powerful radiation sources, arranged in single, double, and triple wire array configurations were tested with Mo and Ag materials, which have both been shown to be powerful radiators, and also mixed with Al to understand opacity effects and how a mixture of two different plasmas radiate. Radiation from the extreme ultraviolet (EUV) range has also been of recent interest due the substantial contribution into total radiation yields. Therefore EUV radiation of M-shell Cu was modeled and benchmarked with spheromak and laser-produced plasma data. Lastly, lasing gain from L-shell Ag is calculated as an application of the aforementioned model to evaluate whether lasing might be occurring in wire array z-pinches. In connection to creating a uniform plasma column to measure lasing lines, the split double planar wire

  18. Application of 2-D simulations to hollow Z-pinch implosions

    SciTech Connect

    Peterson, D. L.; Bowers, R. L.; Brownell, J. H.; Lund, C.; Matuska, W.; McLenithan, K.; Oona, H.; Deeney, C.; Derzon, M.; Spielman, R. B.; Nash, T. J.; Chandler, G.; Mock, R. C.; Sanford, T. W. L.; Matzen, M. K.; Roderick, N. F.

    1997-05-05

    The application of simulations of z-pinch implosions should have at least two goals: first, to properly model the most important physical processes occurring in the pinch allowing for a better understanding of the experiments and second, provide a design capability for future experiments. Beginning with experiments fielded at Los Alamos on the Pegasus I and Pegasus II capacitor banks, we have developed a methodology for simulating hollow z-pinches in two dimensions which has reproduced important features of the measured experimental current drive, spectrum, radiation pulse shape, peak power and total radiated energy (1,2,3). This methodology employs essentially one free parameter, the initial level of the random density perturbations imposed at the beginning of the 2-D simulation, but in general no adjustments to other parameters (such as the resistivity) are required (1). Limitations in the use of this approach include the use of the 3-T, gray diffusion treatment of radiation and the fact that the initial perturbation conditions are not known a priori. Nonetheless, the approach has been successful in reproducing important experimental features of such implosions over a wide variety of timescales (tens of nanoseconds to microseconds), current drives (3 to 16 MA), masses (submilligram to tens of milligrams), initial radii (<1 cm to 5 cm), materials (Al and W) and initial configurations (thin foils and wire arrays with 40 to 240 wires). Currently we are applying this capability to the analysis of recent Saturn and PBFA-Z experiments (4,5). The code results provide insight into the nature of the pinch plasma prior to arrival on-axis, during thermalization and development after peak pinch time. Among other things, the simulation results provide an explanation for the production of larger amounts of radiated energy than would be expected from a simple slug-model kinetic energy analysis and the appearance of multiple peaks in the radiation power. The 2-D modeling has

  19. Application of 2-D simulations to hollow Z-pinch implosions

    SciTech Connect

    Peterson, D.L.; Bowers, R.L.; Brownell, J.H.; Lund, C.; Matuska, W.; McLenithan, K.; Oona, H.; Deeney, C.; Derzon, M.; Spielman, R.B.; Nash, T.J.; Chandler, G.; Mock, R.C.; Sanford, T.W.; Matzen, M.K.; Roderick, N.F.

    1997-05-01

    The application of simulations of z-pinch implosions should have at least two goals: first, to properly model the most important physical processes occurring in the pinch allowing for a better understanding of the experiments and second, provide a design capability for future experiments. Beginning with experiments fielded at Los Alamos on the Pegasus I and Pegasus II capacitor banks, we have developed a methodology for simulating hollow z-pinches in two dimensions which has reproduced important features of the measured experimental current drive, spectrum, radiation pulse shape, peak power and total radiated energy (1,2,3). This methodology employs essentially one free parameter, the initial level of the random density perturbations imposed at the beginning of the 2-D simulation, but in general no adjustments to other parameters (such as the resistivity) are required (1). Limitations in the use of this approach include the use of the 3-T, gray diffusion treatment of radiation and the fact that the initial perturbation conditions are not known {ital a priori}. Nonetheless, the approach has been successful in reproducing important experimental features of such implosions over a wide variety of timescales (tens of nanoseconds to microseconds), current drives (3 to 16 MA), masses (submilligram to tens of milligrams), initial radii ({lt}1cm to 5 cm), materials (Al and W) and initial configurations (thin foils and wire arrays with 40 to 240 wires). Currently we are applying this capability to the analysis of recent Saturn and PBFA-Z experiments (4,5). The code results provide insight into the nature of the pinch plasma prior to arrival on-axis, during thermalization and development after peak pinch time. Among other things, the simulation results provide an explanation for the production of larger amounts of radiated energy than would be expected from a simple slug-model kinetic energy analysis and the appearance of multiple peaks in the radiation power. The 2-D

  20. 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 (0.7-2.3

  1. Plasma density measurements in tungsten wire-array Z-pinches

    SciTech Connect

    Douglass, J. D.; Hammer, D. A.; Pikuz, S. A.; Shelkovenko, T. A.; Blesener, K. S.

    2012-07-15

    Measurements of the plasma density profile near the exploding wires in 1 MA tungsten (W) wire-array Z-pinches have been made using calibrated x-ray absorption. As many as 5 x-ray images per pulse were obtained between 65 and 160 ns after the start of the 100 ns rise time current pulse. Measured W ion densities range from above 10{sup 19}/cm{sup 3} close to the wire to {approx}10{sup 17}/cm{sup 3} about 1 mm away from the wire in the plasma stream. After accurate geometrical registration of the individual wires in each successive image in a pulse using the Genetic Algorithm, the temporal evolution of the axial modulation wavelength distribution of the ablation rate from the wires in each array and the global mass-ablation rate as a function of time are presented.

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

    SciTech Connect

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

    2010-06-01

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

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

    SciTech Connect

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

    2007-10-01

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

  4. Kinetic simulation of neutron production in a deuterium z-pinch.

    SciTech Connect

    Mostrom, C.; Stygar, William A.; Thoma, Carsten; Welch, Dale Robert; Clark, R. E.; Leeper, Ramon Joe; Rose, David V.

    2010-11-01

    We have found computationally that, at sufficiently high currents, half of the neutrons produced by a deuterium z pinch are thermonuclear in origin. Early experiments below 1-MA current found that essentially all of the neutrons produced by a deuterium pinch are not thermonuclear, but are initiated by an instability that creates beam-target neutrons. Many subsequent authors have supported this result while others have claimed that pinch neutrons are thermonuclear. To resolve this issue, we have conducted fully kinetic, collisional, and electromagnetic simulations of the complete time evolution of a deuterium pinch. We find that at 1-MA pinch currents, most of the neutrons are, indeed, beam-target in origin. At much higher current, half of the neutrons are thermonuclear and half are beam-target driven by instabilities that produce a power law fall off in the ion energy distribution function at large energy. The implications for fusion energy production with such pinches are discussed.

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

    SciTech Connect

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

    1996-07-01

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

  6. Nanoscale Ultradense Z -Pinch Formation from Laser-Irradiated Nanowire Arrays

    NASA Astrophysics Data System (ADS)

    Kaymak, Vural; Pukhov, Alexander; Shlyaptsev, Vyacheslav N.; Rocca, Jorge J.

    2016-07-01

    We show that ultradense Z pinches with nanoscale dimensions can be generated by irradiating aligned nanowires with femtosecond laser pulses of relativistic intensity. Using fully three-dimensional relativistic particle-in-cell simulations, we demonstrate that the laser pulse drives a forward electron current in the area around the wires. This forward current induces return current densities of ˜0.1 GA per μ m2 through the wires. The resulting strong, quasistatic, self-generated azimuthal magnetic field pinches the nanowires into hot plasmas with a peak electron density of >9 ×1 024 cm-3 , exceeding 1000 times the critical density. Arrays of these new ultradense nanopinches can be expected to lead to efficient microfusion and other applications.

  7. Dynamics of quasi-spherical Z-pinch implosions with mass redistribution and displacement modification

    SciTech Connect

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

    2012-12-15

    Implosions of (quasi-)spherical loads with mass redistribution and displacement modification are investigated numerically. Both methods can theoretically counterbalance the nonuniformity of magnetic pressure along the load surface and realize quasi-spherical Z-pinch implosions. Mass redistribution is feasible for spherical loads with large radius and weight, while the displacement modification is more suitable for light loads, such as those composed of wire arrays. Simulation results suggest that, for mass redistributed spherical loads, wall instabilities induced by polar mass flows will deform the imploding shell. For prolate spherical loads, in which the wall instability cannot develop, the kinetic energy distribution is disturbed at high latitude. These passive behaviors and their possible mitigation methods, such as reshaping the electrode, are investigated numerically in this paper.

  8. 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

  9. 3D MHD Simulations of Radial Wire Array Z-pinches

    SciTech Connect

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

    2009-01-21

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

  10. 3D MHD Simulations of Radial Wire Array Z-pinches

    NASA Astrophysics Data System (ADS)

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

    2009-01-01

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

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

    SciTech Connect

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

    2009-07-24

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

  12. 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 (Hα, 0.7171 nm and Hβ, 0.6052 nm) and helium-like (Heα, 0.7757 nm and Heβ, 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 Hα line to Heα line using the collisional and radiative model.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Hashimoto, Mitsuhiro; Miyamoto, Tetsu

    2016-07-01

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

  15. 2D radiation-magnetohydrodynamic simulations of SATURN imploding Z-pinches

    SciTech Connect

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

    1995-11-06

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-02-01

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

  17. 250 kA compact linear transformer driver for wire array z-pinch loads

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

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

    SciTech Connect

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

    2015-12-01

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

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

    SciTech Connect

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

    2015-12-15

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

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

    SciTech Connect

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

    2009-01-21

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

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

    SciTech Connect

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

    2009-01-21

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

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

    PubMed

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

    2016-01-20

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

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

    SciTech Connect

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

    2011-09-15

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

  4. 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.

  5. Two-dimensional modeling of the x-radiation output from perturbed Z pinches

    SciTech Connect

    Matuska, W.; Bowers, R.L.; Brownell, J.H.; Lee, H.; Lund, C.M.; Peterson, D.L.; Roderick, N.F.

    1996-04-01

    Two-dimensional radiation magnetohydrodynamic simulations are presented that demonstrate the effects of magnetically driven Rayleigh{endash}Taylor instabilities on the soft x-ray output from Z pinches. Instability models, which reproduce the current drive wave form and match visible framing camera data for instability wavelength and amplitude for implosions on capacitively driven inductive store systems, are used to study the structure of the x-ray output and the spectrum of radiation emitted from the pinch. The results indicate that standard magnetohydrodynamics is capable of reproducing much of the observed data when two-dimensional effects associated with Rayleigh{endash}Taylor instabilities are included. {copyright} {ital 1996 American Institute of Physics.}

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  7. Dynamics of quasi-spherical Z-pinch implosions with mass redistribution and displacement modification

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Ding, Ning; Li, Zheng-Hong; Sun, Shun-Kai; Xue, Chuang; Ning, Cheng; Xiao, De-Long; Huang, Jun

    2012-12-01

    Implosions of (quasi-)spherical loads with mass redistribution and displacement modification are investigated numerically. Both methods can theoretically counterbalance the nonuniformity of magnetic pressure along the load surface and realize quasi-spherical Z-pinch implosions. Mass redistribution is feasible for spherical loads with large radius and weight, while the displacement modification is more suitable for light loads, such as those composed of wire arrays. Simulation results suggest that, for mass redistributed spherical loads, wall instabilities induced by polar mass flows will deform the imploding shell. For prolate spherical loads, in which the wall instability cannot develop, the kinetic energy distribution is disturbed at high latitude. These passive behaviors and their possible mitigation methods, such as reshaping the electrode, are investigated numerically in this paper.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  9. Acceleration of Deuterons to Multi-MeV Energies in Deuterium Gas-Puff Z-Pinch

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    A novel configuration of a deuterium gas-puff z-pinch has been used to generate a short (approx. 20 ns) pulse of multi-MeV ions and neutrons. Even though ion acceleration in z-pinches has not been researched to such an extent as in laser-based sources, obtained results show that z-pinches can reach values comparable to those of state-of-the-art lasers. On the 3 MA GIT-12 generator, the peak neutron yield was 3.6x1012. When a neutron-producing sample was placed onto the axis below a cathode mesh, the neutron yield was increased up to 1013. The emission time of 20 ns implied the neutron production rate of 5x1020 n/s. Neutron energies reached the maximum value of 33 MeV. The comprehensive set of ion diagnostics provided unique information about ion acceleration mechanism. The ion emission was highly anisotropic. Deuterons were trapped in the radial direction whereas a lot of fast ions escaped the z-pinch along the axis. On the axis, the total number of >1 MeV and >25 MeV deuterons was 1016 and 5x1012, respectively. Utilizing these ions offers a real possibility of various applications including the production of short-lived isotopes or fast neutron radiography. This work was supported by the MSMT grants LH13283, LD14089.

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

    SciTech Connect

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

    2014-03-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

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

    SciTech Connect

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

    2009-05-15

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

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

    SciTech Connect

    Sheehey, P.T.

    1994-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    SciTech Connect

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

    2015-02-15

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

  17. A Experimental Study of the Dynamics of X-Pinch and Z-Pinch Plasmas

    NASA Astrophysics Data System (ADS)

    Kalantar, Daniel Husayn

    X-pinch experiments have been carried out using 12 to 100 μm diameter Al wires with peak currents of 330 to 380 kA. Two wires were placed between the output electrodes of a low inductance pulser so as to cross and touch at a single point, resulting in intense K-shell soft x-ray radiation from a sub-millimeter high temperature (300 to 700 eV) and density (2 times 10^{19} to 1 times 10^{21 } cm^{-3}) plasma at the cross point. Single wire z-pinch experiments were conducted for comparison. Additional x-pinch experiments were carried out using up to eight wires at peak currents from 280 kA to 1.0 MA. Intense soft x-ray emission from the cross region occurs in short bursts. Filtered GaAs:Cr photoconducting diodes and streaked x-ray pinhole images show individual bursts lasting <=1 ns. Time-integrated K-shell spectra obtained with a curved KAP crystal spectrograph were used to determine the electron temperature and density for individual bright spots. A sub-ns pulsed nitrogen laser was used for time -resolved schlieren and interferometry measurements of the unstable expansion of a coronal plasma that develops around the wires. The implosion and re-expansion of the corona at the x-pinch cross region was observed immediately prior to x-ray emission. Jets of plasma were ejected along the axis, as recorded in schlieren images and visible light frame images. Late in the pulse, gaps formed along the axis with electron density <=5 times 10^{17} cm^{-3}. Spectra indicated the presence of electron beams carrying the current in these gaps. Interferometry measurements provided the electron density profile late in the current pulse. Individual bursts of x-ray emission from one x -pinch were used to record a shadow of the dense core plasma at the initial wire position of a parallel x-pinch or z -pinch. This core expanded uniformly within the corona, surviving until it was disrupted by the implosion of the corona prior to soft x-ray emission. The Bennett relation is used to estimate

  18. Deuterium gas puff Z-pinch at currents of 2 to 3 mega-ampere

    NASA Astrophysics Data System (ADS)

    Klir, D.; Shishlov, A. V.; Kubes, P.; Rezac, K.; Fursov, F. I.; Kokshenev, V. A.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Labetsky, A. Yu.; Ratakhin, N. A.

    2012-03-01

    Deuterium gas-puff experiments have been carried out on the GIT-12 generator at the Institute of High Current Electronics in Tomsk. The emphasis was put on the study of plasma dynamics and neutron production in double shell gas puffs. A linear mass density of deuterium (D2) varied between 50 and 85 μg/cm. Somewhat problematic was a spread of the D2 gas at a large diameter in the central anode-cathode region. The generator operated in two regimes, with and without a plasma opening switch (POS). When the POS was used, a current reached a peak of 2.7 MA with a 200 ns rise time. Without the POS, a current rise time approached 1500 ns. The influence of different current rise times on neutron production was researched. Obtained results were important for comparison of fast deuterium Z-pinches with plasma foci. Average DD neutron yields with and without the POS were about 1011. The neutron yield seems to be dependent on a peak voltage at the Z-pinch load. In all shots, the neutron emission started during stagnation. At the beginning of the neutron production, the neutron emission correlated with soft x-rays and a significant fraction of neutrons could be explained by the thermonuclear mechanism. Nevertheless, a peak of the neutron emission occurred 40 ns after a soft x-ray peak. At this very moment, hard x-rays above 1 MeV were detected and a rapid expansion with a velocity of 3×105 m/s was observed. In the case of the POS, 1 MeV widths of radial neutron spectra implied that there are deuterons with the energy above 200 keV moving in the radial direction. On the basis of D2 gas puff experiments in the 0.3-17 MA region, the neutron yield dependence on a current as Y∝I3.0±0.2 was proposed.

  19. Development and characterization of a Z-pinch-driven hohlraum high-yield inertial confinement fusion target concept

    NASA Astrophysics Data System (ADS)

    Cuneo, Michael E.; Vesey, Roger A.; Porter, John L.; Chandler, Gordon A.; Fehl, David L.; Gilliland, Terrance L.; Hanson, David L.; McGurn, John S.; Reynolds, Paul G.; Ruggles, Laurence E.; Seamen, Hans; Spielman, Rick B.; Struve, Ken W.; Stygar, William A.; Simpson, Walter W.; Torres, Jose A.; Wenger, David F.; Hammer, James H.; Rambo, Peter W.; Peterson, Darrell L.; Idzorek, George C.

    2001-05-01

    Initial experiments to study the Z-pinch-driven hohlraum high-yield inertial confinement fusion (ICF) concept of Hammer, Tabak, and Porter [Hammer et al., Phys. Plasmas 6, 2129 (1999)] are described. The relationship between measured pinch power, hohlraum temperature, and secondary hohlraum coupling ("hohlraum energetics") is well understood from zero-dimensional semianalytic, and two-dimensional view factor and radiation magnetohydrodynamics models. These experiments have shown the highest x-ray powers coupled to any Z-pinch-driven secondary hohlraum (26±5 TW), indicating the concept could scale to fusion yields of >200 MJ. A novel, single-sided power feed, double-pinch driven secondary that meets the pinch simultaneity requirements for polar radiation symmetry has also been developed. This source will permit investigation of the pinch power balance and hohlraum geometry requirements for ICF relevant secondary radiation symmetry, leading to a capsule implosion capability on the Z accelerator [Spielman et al., Phys. Plasmas 5, 2105 (1998)].

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

    SciTech Connect

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

    2009-01-21

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

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

    PubMed

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

    2016-05-13

    Fusion yields from dense, Z-pinch plasmas are known to scale with the drive current, which is favorable for many potential applications. Decades of experimental studies, however, show an unexplained drop in yield for currents above a few mega-ampere (MA). In this work, simulations of DD Z-Pinch plasmas have been performed in 1D and 2D for a constant pinch time and initial radius using the code Lsp, and observations of a shift in scaling are presented. The results show that yields below 3 MA are enhanced relative to pure thermonuclear scaling by beamlike particles accelerated in the Rayleigh-Taylor induced electric fields, while yields above 3 MA are reduced because of energy lost by the instability and the inability of the beamlike ions to enter the pinch region. PMID:27232025

  2. Innovative Approach for Enhancing Shaped X-ray Production in Z-pinches*

    NASA Astrophysics Data System (ADS)

    Kantsyrev, V. L.; Safronova, A. S.; Esaulov, A. A.; Kindel, J. M.; Williamson, K. M.; Shrestha, I.; Osborne, G. C.; Weller, M. E.; Ouart, N. D.; Shlyaptseva, V.; Chuvatin, A. S.; Rudakov, L. I.; Velikovich, A. L.

    2010-11-01

    Among z-pinch loads tested at 1.7 MA Zebra generator, planar wire arrays (PWAs) were found to be the best x-ray radiators. PWAs were recently highlighted (PRL 104, 125001, 2010) as potential sources for a new ICF multisource compact hohlraum setup at multi-MA generators. Recent performance optimization of PWA, which exhibits a large resistive energy/power gain and a small, mm-scale size, is reviewed. The anisotropy of radiation yields from single- and double-PWAs that might be caused by opacity effects was observed: higher yield was orthogonally to an array plane or along wire rows in single- and double-PWA (DPWA), respectively. Skewed DPWA implosions, which produce an axial magnetic field to reduce instabilities, generate higher Te/Ne compared to a standard DPWA. Feasible x-ray pulse shaping was demonstrated with DPWA and triple-PWA by varying array composition and parameters. The studies were supported by non-LTE kinetic, WADM, and MHD simulations. * This work was supported by NNSA under DOE Cooperative Agreements DE-FC52-06NA27586, DE-FC52-06NA27588, and in part by DE-FC52-06NA27616.

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

    NASA Astrophysics Data System (ADS)

    Appelbe, B.; Chittenden, J.

    2015-10-01

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

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

    SciTech Connect

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

    2015-07-15

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

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

    PubMed

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

    2015-08-01

    High energy photons are measured for the first time in wire-array Z-pinch experiments on the Primary Test Stand (PTS) which delivers a current up to 8 MA with a rise time of 70 ns. A special designed detecting system composed of three types of detectors is used to measure the average energy, intensity, and pulse waveform of high energy photons. Results from Pb-TLD (thermoluminescence dosimeter) detector indicate that the average energy is 480 keV (±15%). Pulse shape of high energy photons is measured by the photodiode detector consisted of scintillator coupled with a photodiode, and it is correlated with soft x-ray power by the same timing signal. Intensity is measured by both TLD and the photodiode detector, showing good accordance with each other, and it is 10(10) cm(-2) (±20%) at 2 m in the horizontal direction. Measurement results show that high energy photons are mainly produced in pinch regions due to accelerated electrons. PTS itself also produces high energy photons due to power flow electrons, which is one order smaller in amplitude than those from pinch region. PMID:26329192

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  7. Characterisation of the Current Switch Mechanism in Two-stage Wire Array Z-pinches

    NASA Astrophysics Data System (ADS)

    Burdiak, Guy; Lebedev, S.; Harvey-Thompson, A.; Hall, G.; Swadling, G.; Suzuki-Vidal, F.; Bland, S.; Pickworth, L.; de Grouchy, P.; Suttle, L.; Waisman, E.

    2015-11-01

    We describe the operation of a two-stage wire array z-pinch driven by the 1.4 MA, 240 ns rise-time Magpie generator at Imperial College London. In this setup an inverse wire array acts as a fast current switch, delivering a current pre-pulse into a cylindrical load wire array, before rapidly switching the majority of the generator current into the load after a 100-150 ns dwell time. Preconditioning of the load array dramatically alters the ensuing implosion dynamics; the ablation phase is eliminated and no trailing mass remains at the initial array radius during the final implosion. The main current switch occurs as the inverse array begins to explode and plasma expands into the load region. Electrical and imaging diagnostics indicate that the main current switch may evolve as a plasma flow switch, driven by the expansion of a magnetic cavity and plasma bubble along the length of the load array. Analysis of implosion trajectories suggests that approximately 1 MA switches into the load in 100 ns. Attempts to measure the current profile throughout the current switch will be presented. Potential scaling of the device to higher current machines is discussed.

  8. Operation of Two-stage Wire Array Z-pinches on the Magpie Generator

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Burdiak, Guy; Lebedev, S.; Harvey-Thompson, A.; Hall, G.; Swadling, G.; Suzuki-Vidal, F.; Bland, S.; Suttle, L.; Waisman, E.; Wang, G.; Yang, Q.

    2015-11-01

    We describe the operation of two-stage wire array z-pinches driven by the 1.4MA, 240ns Magpie generator at Imperial College. In this setup, an inverse wire array acts as a fast current switch, delivering a 20ns, 5kA current pre-pulse into a cylindrical load array, before rapidly switching the majority of the generator current into the load after a 100ns dwell time. Measurements of load resistivity and energy deposition during the pre-pulse suggest significant bulk heating of the array mass occurs, leaving it in a mixed liquid-vapour state. Preconditioning of the load dramatically alters the ensuing implosion dynamics; the ablation phase is eliminated, together with trailing mass during the final implosion. The main current switch occurs as the inverse array explodes and plasma expands into the load region. Electrical and imaging diagnostics indicate that the main current switch may evolve as a plasma flow switch, driven by the expansion of a magnetic cavity along the length of the load array. Analysis of implosion trajectories suggests that approximately 1MA switches into the load in 100ns, corresponding to a doubling of the generator dI/dt. Attempts to measure the current profile throughout the current switch will be presented. In addition, we present results from preconditioned x-pinch experiments, and attempts to perform point projection radiography of preconditioned single wires by fielding an x-pinch in parallel with a two-stage array.

  9. Preliminary Results of Cone Z-Pinch Device with 5 kJ

    NASA Astrophysics Data System (ADS)

    Abdel-kader, M. E.; Abd Al-Halim, M. A.; Shagar, A. M.; Eltayeb, H. A.; Algamal, H. A.; Saudy, A. H.

    2013-10-01

    The Cone Z-Pinch Experiment with 5 kJ is designed, constructed and operated. The electric discharge takes place between an upper ring electrode and a lower pin electrode creating plasma sheath in shape of cone. The preliminary experimental results using Helium gas in discharge show that the discharge period is 35 μs, the total system inductance is 287 nH, and the total system resistance is 15 mΩ. The breakdown curve shows a minimum breakdown value at 0.2 torr pressure. The cone plasma is confined by electromagnetic force and plasma inductance has its maximum value at the pinch. The plasma current has a maximum value of 53 kA at the axis of the discharge tube. The experimental results showed that a time of 2.1 μs at least is required for the pinch to occur and that both the pinch time and the duration time decrease with increasing the charging voltage.

  10. The anisotropic redistribution of free energy for gyrokinetic plasma turbulence in a Z-pinch

    NASA Astrophysics Data System (ADS)

    Navarro, Alejandro Bañón; Teaca, Bogdan; Jenko, Frank

    2016-04-01

    For a Z-pinch geometry, we report on the nonlinear redistribution of free energy across scales perpendicular to the magnetic guide field, for a turbulent plasma described in the framework of gyrokinetics. The analysis is performed using a local flux-surface approximation, in a regime dominated by electrostatic fluctuations driven by the entropy mode, with both ion and electron species being treated kinetically. To explore the anisotropic nature of the free energy redistribution caused by the emergence of zonal flows, we use a polar coordinate representation for the field-perpendicular directions and define an angular density for the scale flux. Positive values for the classically defined (angle integrated) scale flux, which denote a direct energy cascade, are shown to be also composed of negative angular sections, a fact that impacts our understanding of the backscatter of energy and the way in which it enters the modeling of sub-grid scales for turbulence. A definition for the flux of free energy across each perpendicular direction is introduced as well, which shows that the redistribution of energy in the presence of zonal flows is highly anisotropic.