Publications

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Scaling of X pinches from 1 MA to 6 MA

Sinars, Daniel S.; McBride, Ryan D.; Wenger, D.F.; Cuneo, M.E.; Yu, Edmund Y.; Harding, Eric H.; Hansen, Stephanie B.; Ampleford, David A.; Jennings, Christopher A.

This final report for Project 117863 summarizes progress made toward understanding how X-pinch load designs scale to high currents. The X-pinch load geometry was conceived in 1982 as a method to study the formation and properties of bright x-ray spots in z-pinch plasmas. X-pinch plasmas driven by 0.2 MA currents were found to have source sizes of 1 micron, temperatures >1 keV, lifetimes of 10-100 ps, and densities >0.1 times solid density. These conditions are believed to result from the direct magnetic compression of matter. Physical models that capture the behavior of 0.2 MA X pinches predict more extreme parameters at currents >1 MA. This project developed load designs for up to 6 MA on the SATURN facility and attempted to measure the resulting plasma parameters. Source sizes of 5-8 microns were observed in some cases along with evidence for high temperatures (several keV) and short time durations (<500 ps).

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Bright spots in 1 MA X pinches as a function of wire number and material

Proposed for publication in Physics of Plasmas.

Ampleford, David A.; Cuneo, M.E.; Wenger, D.F.

Bright, intense x-ray sources with extreme plasma parameters (micropinch plasmas) have previously been characterized at 0.1-0.4 MA, but the scaling of such sources at higher current is poorly understood. The x-ray source size and radiation power of 1 MA X pinches were studied as a function of wire material (Al, Ti, Mo, and W) and number (1-, 2-, 8-, 32-, and 64-wire configurations). The smallest bright spots observed were from 32-wire tungsten X pinches, which produced {le} 11-16 {micro}m, {approx}2 J, 1-10 GW sources of 3-5 keV radiation.

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Z-Beamlet: a multi-KJ TW-class laser for backlit x-radiography applications on the Z-Accelerator

Atherton, B.W.; Gonzales, Rita A.; Gurrieri, Thomas G.; Herrmann, Mark H.; Mulville, Thomas D.; Neely, Kelly A.; Rambo, Patrick K.; Rovang, Dean C.; Ruggles, Larry R.; Smith, Ian C.; Schwarz, Jens S.; Simpson, Walter W.; Sinars, Daniel S.; Speas, Christopher S.; Tafoya-Porras, Belinda T.; Wenger, D.F.; Young, Ralph W.; Adams, Richard G.; Bennett, Guy R.; Campbell, David V.; Carroll, Malcolm; Claus, Liam D.; Edens, Aaron E.; Geissel, Matthias G.

Abstract not provided.

X-ray optics on the Z-Accelerator backlit with the Z-Beamlet Laser & Z-Petawatt Laser systems

Gonzales, Rita A.; Gurrieri, Thomas G.; Herrmann, Mark H.; Mulville, Thomas D.; Neely, Kelly A.; Rambo, Patrick K.; Rovang, Dean C.; Ruggles, Larry R.; Schwarz, Jens S.; Adams, Richard G.; Simpson, Walter W.; Sinars, Daniel S.; Smith, Ian C.; Speas, Christopher S.; Tafoya-Porras, Belinda T.; Wenger, D.F.; Young, Ralph W.; Edens, Aaron E.; Atherton, B.W.; Bennett, Guy R.; Campbell, David V.; Carroll, Malcolm; Claus, Liam D.; Geissel, Matthias G.

Abstract not provided.

1- and 2-frame monochromatic x-ray imaging of NIF-like capsules on Z and future higher-energy higher-resolution 2- & 4-frame x-radiography plans for ZR

Bennett, Guy R.; Campbell, David V.; Claus, Liam D.; Foresi, James S.; Johnson, Drew J.; Jones, Michael J.; Keller, Keith L.; Leifeste, Gordon T.; McPherson, Leroy A.; Mulville, Thomas D.; Neely, Kelly A.; Sinars, Daniel S.; Herrmann, Mark H.; Rambo, Patrick K.; Rovang, Dean C.; Ruggles, Larry R.; Simpson, Walter W.; Speas, Christopher S.; Wenger, D.F.; Smith, Ian C.; Cuneo, M.E.; Adams, Richard G.; Atherton, B.W.; Barnard, Wilson J.; Beutler, David E.; Burr, Robert A.

Abstract not provided.

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

Proposed for publication in Physical Review Letters.

Sinars, Daniel S.; Cuneo, M.E.; Yu, Edmund Y.; Bliss, David E.; Nash, Thomas J.; Deeney, Christopher D.; Mazarakis, Michael G.; Wenger, D.F.

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

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1- to 10-keV x-ray backlighting of annular wire arrays on the Sandia Z-machine using bent-crystal imaging techniques

Proceedings of SPIE - The International Society for Optical Engineering

Sinars, Daniel S.; Wenger, D.F.; Cuneo, M.E.; Bennett, Guy R.; Anderson, Jessica E.; Porter, John L.; Rambo, Patrick K.; Rovang, Dean C.; Smith, Ian C.

Annular wire array implosions on the Sandia Z-machine can produce >200 TW and 1-2 MJ of soft x rays in the 0.1-10 keV range. The x-ray flux and debris in this environment present significant challenges for radiographic diagnostics. X-ray backlighting diagnostics at 1865 and 6181 eV using spherically-bent crystals have been fielded on the Z-machine, each with a ~0.6 eV spectral bandpass, 10 μm spatial resolution, and a 4 mm by 20 mm field of view. The Z-Beamlet laser, a 2-TW, 2-kJ Nd:glass laser (λ=527 nm), is used to produce 0.1-1 J x-ray sources for radiography. The design, calibration, and performance of these diagnostics is presented.

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[Copy of characteristics and scaling of tungsten-wire-array z-pinch implosion dynamics at 20 MA.]

Proposed for publication in Physics of Plasmas.

Vesey, Roger A.; Yu, Edmund Y.; Nash, Thomas J.; Bliss, David E.; Bennett, Guy R.; Sinars, Daniel S.; Simpson, Walter W.; Ruggles, Larry R.; Wenger, D.F.; Garasi, Christopher J.; Aragon, Rafael A.; Fowler, William E.; Johnson, Drew J.; Keller, Keith L.; McGurn, John S.; Mehlhorn, Thomas A.; Speas, Christopher S.; Struve, Kenneth W.; Stygar, William A.; Chandler, Gordon A.

Abstract not provided.

Z facility diagnostic system for high energy density physics at Sandia National Laboratories

Leeper, Ramon J.; Deeney, Christopher D.; Dunham, Gregory S.; Fehl, David L.; Franklin, James K.; Hawn, Rona E.; Hall, Clint A.; Hurst, Michael J.; Jinzo, Tanya D.; Jobe, Daniel O.; Leeper, Ramon J.; Joseph, Nathan R.; Knudson, Marcus D.; Lake, Patrick W.; Lazier, Steven E.; Lucas, J.; McGurn, John S.; Manicke, Matthew P.; Mock, Raymond M.; Moore, T.C.; Nash, Thomas J.; Bailey, James E.; Nelson, Alan J.; Nielsen, D.S.; Olson, Richard E.; Pyle, John H.; Rochau, G.A.; Ruggles, Larry R.; Ruiz, Carlos L.; Sanford, Thomas W.; Seamen, Johann F.; Bennett, Guy R.; Simpson, Walter W.; Sinars, Daniel S.; Speas, Christopher S.; Stygar, William A.; Wenger, D.F.; Seamen, Johann J.; Carlson, Alan L.; Chandler, Gordon A.; Cooper, Gary W.; Cuneo, M.E.

Abstract not provided.

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

Physics of Plasmas

Cuneo, M.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, Larry R.; Seamen, Hans; Spielman, Rick B.; Struve, Kenneth W.; Stygar, William A.; Simpson, Walter W.; Torres, Jose A.; Wenger, D.F.; Hammer, James H.; Rambo, Peter W.; Peterson, Darrell L.; Idzorek, George C.

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)]. © 2001 American Institute of Physics.

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Measurement of the efficiency of gold transmission gratings in the 100 to 5000 eV photon energy range

Review of Scientific Instruments

Ruggles, Larry R.; Cuneo, M.E.; Porter, J.L.; Wenger, D.F.; Simpson, Walter W.

Three x-ray spectrometers, each with a transmission grating dispersion element, are routinely used at the Z soft x-ray facility to measure the spectrum and temporal history of the absolute soft x-ray power emitted from z-pinch and hohlraum radiation sources. Our goal is to make these measurements within an accuracy of ±10%. We periodically characterize the efficiency of the gratings used in the spectrometers by using an electron-impact soft x-ray source, a monochromator, grazing-incidence mirrors, thin filters, and an x-ray charge-coupled device (CCD) detector. We measure the transmission efficiency of the gratings at many photon energies for several grating orders. For each grating, we calculate efficiency as a function of photon energy using published optical constants of gold and multiple-slit Fraunhofer diffraction theory and fit the calculation to the measurements using the physical parameters of the grating as variables. This article describes the measurement apparatus and calibration techniques, discusses the grating efficiency calculation and fitting procedure, and presents recent results. © 2001 American Institute of Physics.

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27 Results
27 Results