A5008717301- High-pressure geophysics and materials
- Laser-Plasma Interactions and Diagnostics
- Pulsed Power Technology Applications
- High-Velocity Impact and Material Behavior
- Electromagnetic Launch and Propulsion Technology
- Diamond and Carbon-based Materials Research
- Energetic Materials and Combustion
- Particle accelerators and beam dynamics
- Nuclear Physics and Applications
- Astro and Planetary Science
- Scientific Measurement and Uncertainty Evaluation
- Laser-induced spectroscopy and plasma
- Geological and Geochemical Analysis
- Gyrotron and Vacuum Electronics Research
- Ion-surface interactions and analysis
- Gas Dynamics and Kinetic Theory
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- earthquake and tectonic studies
- Plasma Diagnostics and Applications
- Metal and Thin Film Mechanics
- Force Microscopy Techniques and Applications
- Industrial Automation and Control Systems
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
Sandia National Laboratories
2014-2024
Lawrence Livermore National Laboratory
2007-2024
Washington State University
2016
Sandia National Laboratories California
2008-2013
National Technical Information Service
2005-2008
Office of Scientific and Technical Information
2005-2008
Los Alamos National Laboratory
2007
Atomic Weapons Establishment
2007
United States Naval Research Laboratory
1995-2006
University of Oklahoma
2002
Pulsed power accelerators compress electrical energy in space and time to provide versatile experimental platforms for high density inertial confinement fusion science. The 80-TW “Z” pulsed facility at Sandia National Laboratories is the largest device world today. Z discharges up 22 MJ of stored its capacitor banks into a current pulse that rises 100 ns peaks as 30 MA low-inductance cylindrical targets. Considerable progress has been made over past 15 years use precision scientific tool....
Pushing a pressure standard A challenge for understanding systems at extreme conditions is knowing the exact which exotic behaviors occur. This situation caused by lack of an absolute pressure-density relationship calibrants. Fratanduono et al. conducted series dynamic compression observations on platinum and gold to establish high-pressure scale these metals up terapascal (see Perpsective Jeanloz). work provides robust calibration when using standards in devices such as diamond anvil cells....
The intense magnetic field produced by the 20 MA Z accelerator is used as an impulsive pressure source to accelerate metal flyer plates high velocity for purpose of performing plate impact, shock wave experiments. This capability has been significantly enhanced recently developed pulse shaping Z, which enables tailoring rise time peak current a specific material and drive avoid formation within during acceleration. Consequently, full advantage can be taken available achieve maximum possible...
Multiple experimental campaigns have been executed to study the implosions of initially solid beryllium (Be) liners (tubes) on Z pulsed-power accelerator. The were driven by current pulses that rose from 0 20 MA in either 100 or 200 ns (200 for pulse shaping experiments). These studies conducted support recently proposed Magnetized Liner Inertial Fusion concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)], as well exploring novel equation-of-state measurement techniques. experiments used...
Iron was ramp-compressed over timescales of 3 ≤ t(ns) 300 to study the time-dependence α→ε (bcc→hcp) phase transformation. Onset stresses (σα→ε) for transformation ∼14.8-38.4 GPa were determined through laser and magnetic ramp-compression techniques where transition strain-rate varied between 106 ≤μ̇α→ε(s−1) 5×108. We find σα→ε= 10.8 + 0.55 ln(μ̇α→ε) μ̇α→ε < 106/s 1.15(μ̇α→ε)0.18 > 106/s. This μ̇ response is quite similar recent results on incipient plasticity in Fe [Smith et...
Nanosecond in situ x-ray diffraction and simultaneous velocimetry measurements were used to determine the crystal structure pressure, respectively, of ramp-compressed aluminum at stress states between 111 475 GPa. The solid-solid Al phase transformations, fcc--hcp hcp--bcc, are observed $216\ifmmode\pm\else\textpm\fi{}9$ $321\ifmmode\pm\else\textpm\fi{}12\text{ }\text{ }\mathrm{GPa}$, with bcc persisting high-pressure crystallographic texture hcp phases suggests close-packed or nearly...
An absolute stress-density path for shocklessly compressed copper is obtained to over 450 GPa. A magnetic pressure drive temporally tailored generate shockless compression waves through 2.5-mm-thick samples. The free-surface velocity data analyzed Lagrangian sound using the iterative analysis (ILA) technique, which relies upon method of characteristics. We correct effects strength and plastic work heating determine an isentropic path. By assuming a Debye model heat capacity, we can further...
A technique has previously been developed on the Z accelerator [R. B. Spielman et al., Phys. Plasmas 5, 2105 (1998)] to generate ramped compression waves in condensed matter for equation-of-state studies [C. A. Hall, J. R. Asay, M. D. Knudson, W. Stygar, Spielman, T. Pointon, Reisman, Toor, and C. Cauble, Rev. Sci. Instrum. 72, 3587 (2001)] by using Lorentz force push solid electrodes rather than drive a pinch. This now extended multimegabar pressures shaping current pulse significantly...
Using a magnetic pressure drive, an absolute measurement of stress and density along the principal compression isentrope is obtained for solid aluminum to 240GPa. Reduction free-surface velocity data relies on backward integration technique, with approximate accounting unknown systematic errors in experimental timing. Maximum uncertainties are ±4.7% ±1.4% density, small enough distinguish between different equation-of-state (EOS) models. The result agrees well tabular EOS that uses empirical...
A magnetic loading technique was used to study the strength of pure, annealed, and cold-rolled polycrystalline tantalum under planar ramp at strain rates ∼106/s. Both initial yield flow after compression peak stresses 18 GPa were determined. For sample thicknesses ranging from 0.5–6.0 mm, it found that elastic limit ∼3.2 GPa, corresponding a 1.6 for annealed Ta sharply defined essentially independent thickness. After yielding, relaxation longitudinal stress occurred greater than ∼0.5...
Current pulse shaping techniques, originally developed for planar dynamic material experiments on the Z-machine [M. K. Matzen et al., Phys. Plasmas 12, 055503 (2005)], are adapted to design of controlled cylindrical liner implosions. By driving these targets with a current shape that prevents shock formation inside liner, heating is avoided along corresponding decrease in electrical conductivity ahead magnetic diffusion wave penetrating liner. This results an imploding significant amount its...
Magnetically-driven, planar shockless-compression experiments to multi-megabar pressures were performed on tantalum samples using a stripline target geometry. Free-surface velocity waveforms measured in 15 cases; nine of these dual-sample configuration with two different thicknesses opposing electrodes, and six single-sample bare electrode opposite the sample. Details are given application inverse Lagrangian analysis (ILA) data, including potential sources error. The most significant source...
A magnetic loading technique was used to ramp load single-crystal [100] lithium fluoride specimens peak stresses of 5–114 GPa. Wave analysis in situ particle velocity profiles estimate the compressive strength LiF at stress. It found that increased with stress and showed two distinct regions hardening; first is believed be governed by strain hardening second pressure hardening. The quasielastic obtained from initial part unloading shown saturate about 1.3% for greater than approximately 30...
We have developed the design of Thor: a pulsed power accelerator that delivers precisely shaped current pulse with peak value as high 7 MA to strip-line load. The magnetic pressure achieved within 1-cm-wide load is 100 GPa. Thor powered by many 288 decoupled and transit-time isolated bricks. Each brick consists single switch two capacitors connected electrically in series. bricks can be individually triggered achieve degree tailoring. Because impedance matched throughout, capacitor energy...
An understanding of the mechanical and optical properties lithium fluoride (LiF) is essential to its use as a transparent tamper window for dynamic materials experiments. In order improve models this material, we applied iterative Lagrangian analysis ten independent sets data from magnetically driven planar shockless compression experiments on single crystal [100] LiF pressures high 350 GPa. We found that response disagreed with prevalent tabular equation state commonly used interpret also...
We report on direct, radiographic measurement of the stagnation phase a magnetically driven liner implosion. The is filled with liquid deuterium and imploded to minimum radius 440 μm (radial convergence ratio 7.7) over 300 ns, achieving density ≈10 g/cm3. measured confinement time ≈14 compared 16 ns from 1D simulations. A comparison profiles 2D simulations shows deviation in reflected shock trajectory areal density. Additionally, magneto Rayleigh-Taylor instability causes enhanced...
A magnetic loading technique was used to ramp load pure aluminum and 6061 alloy peak stresses of approximately 29GPa. The rate 106∕s, followed by unloading from stress at a about 105∕s. samples had impurity levels ranging 10ppmto0.5wt% average grain sizes in the range 144–454μm. prepared either T6 condition with 5–50μm, or T0 heat treatment size 40μm. wave profile estimate compressive strength during unloading. It found that estimated increased for all materials change insensitive initial...
Abstract Magnetic loading was used to shocklessly compress four different metals extreme pressures. Velocimetry monitored the behavior of material as it loaded a desired peak state and then decompressed back down lower Two distinct analysis methods, including wave profile novel Bayesian calibration approach, were employed estimate quantitative strength metrics associated with reversal. Specifically, we report for first time on estimates tantalum, gold, platinum, iridium under shockless...
A technique has been developed at the Sandia Z Accelerator using a magnetically driven flyer plate with double-ramp pulse shape to generate in test sample steady shock followed 10–100 ns later by quasi-isentropic ramped compression wave. Based on velocity data from multiple samples of differing thicknesses, based backward minimization is presented that allows determination material response along an elevated isentrope through state. Data quasi-isentropically compressed shock-melted tin...
We report on a series of experiments that use high-power lasers to ramp-compress aluminum (Al) up 475 GPa. Under this quasi-isentropic compression, Al remains in the solid state and two solid–solid phase transformations are observed. In situ x-ray diffraction is performed detect crystal structure. A velocimetry diagnostic measures particle velocities order infer pressure sample. show transition, consistent with transformation hexagonal close-packed (hcp) structure, occurs at 216 ± 9 At...
We have developed a conceptual design of next-generation pulsed-power accelerator that is optimized for megajoule-class dynamic-material-physics experiments. Sufficient electrical energy delivered by the to physics load achieve---within centimeter-scale samples---material pressures as high 1 TPa. The based on an architecture founded three concepts: single-stage electrical-pulse compression, impedance matching, and transit-time-isolated drive circuits. prime power source consists 600...
Enabling technologies are being developed at Sandia National Laboratories to improve the performance and flexibility of compact pulsed-power drivers for magnetically driven dynamic materials properties research. We have designed a modular system that is capable precision current pulse shaping through selective triggering pulse-forming components into disk transmission line feeding strip load. The composed 240 200-kV 60-kA modules in low-inductance configuration producing 250-350 kbar...