A5082426372- Laser-Plasma Interactions and Diagnostics
- High-pressure geophysics and materials
- Electromagnetic Launch and Propulsion Technology
- Energetic Materials and Combustion
- Particle accelerators and beam dynamics
- Pulsed Power Technology Applications
- Magnetic confinement fusion research
- Gyrotron and Vacuum Electronics Research
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Organic and Inorganic Chemical Reactions
- Laser-induced spectroscopy and plasma
- Diamond and Carbon-based Materials Research
- High-Velocity Impact and Material Behavior
- Fusion materials and technologies
- Chemical Synthesis and Reactions
- Electrostatic Discharge in Electronics
- Vacuum and Plasma Arcs
- Organic Chemistry Cycloaddition Reactions
- Coordination Chemistry and Organometallics
- Atomic and Molecular Physics
- Silicon Carbide Semiconductor Technologies
- Material Dynamics and Properties
- Chemical Reaction Mechanisms
Energetiq Technology (United States)
2023-2024
University of California, San Diego
2020-2021
Voss Scientific (United States)
2020
Idaho State University
2018-2020
University of Rochester
2017-2019
Energetics (United States)
2017-2019
Sandia National Laboratories
2015-2017
Sandia National Laboratories California
2016
Lawrence Livermore National Laboratory
2003-2013
Los Alamos National Laboratory
2007-2012
We have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and 800. The are based on an accelerator architecture that is founded concepts: single-stage electrical-pulse compression impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. prime power source each machine consists 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, which powered by 5-GW bricks parallel. (A brick a single...
A capability to produce quasi-isentropic compression of solids using pulsed magnetic loading on the Z accelerator has recently been developed and demonstrated [C. A. Hall, Phys. Plasmas 7, 2069 (2000)]. This technique allows planar, continuous materials stresses approaching 1.5 Mbar. In initial stages development, experimental configuration used a magnetically loaded material cup or disk as sample interest pressed into conductor. installation caused distortions that limited ability attach...
A new method for shockless compression and acceleration of solid materials is presented. plasma reservoir pressurized by a laser-driven shock unloads across vacuum gap piles up against an Al sample thus providing the drive. The rear surface velocity was measured with line VISAR, used to infer load histories. These peaked between approximately 0.14 0.5 Mbar strain rates 10(6)-10(8) s(-1). Detailed simulations suggest that apart from layers samples can remain close room temperature isentrope....
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...
Isentropic compression experiments (ICE) have been performed on the Z accelerator facility at Sandia National Laboratory. We describe experimental design that used large magnetic fields to slowly compress samples pressures in excess of 400 kbar. Velocity wave profile measurements were analyzed yield isentropic equations state (EOS). The method can also material strength properties. magnetohydronamic simulations and results “square short” configuration copper discuss ICE EOS with this...
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...
We have developed a conceptual design of 15-TW pulsed-power accelerator based on the linear-transformer-driver (LTD) architecture described by Stygar [W. A. et al., Phys. Rev. ST Accel. Beams 18, 110401 (2015)]. The driver will allow multiple, high-energy-density experiments per day in university environment and, at same time, enable both fundamental and integrated that are scalable to larger facilities. In this design, many individual energy storage units (bricks), each composed two...
A linear transformer driver (LTD) generator capable of delivering up to 0.9 MA current pulses with 160 ns rise time has been assembled and commissioned at University California San Diego. The machine is an upgrade the LTD-III pulser from Sandia National Laboratories, consisting 40 capacitors 20 spark gap switches, arranged in a 20-brick configuration. was modified addition new trigger system, active premagnetization inductive cores, vacuum chamber multiple diagnostic ports, power feed couple...
We have conceived a new class of prime-power sources for pulsed-power accelerators: impedance-matched Marx generators (IMGs). The fundamental building block an IMG is brick, which consists two capacitors connected electrically in series with single switch. An comprises stage or several stages distributed axially and series. Each powered by brick bricks azimuthally within the parallel. multistage drive coaxial transmission line conical center conductor. When are triggered sequentially to...
Single crystals of cyclotetramethylene tetranitramine (HMX) were isentropically compressed perpendicular to (010) and (011) faces at the Sandia Z-Machine. A 50GPa ramped magnetic pressure load about 200ns rise time loaded four specimens each orientation. HMX from 300–600μm thick. Velocity histories rear crystal measured by Doppler velocimetry. Although a phase change in 27GPa has been proposed based upon isothermal data, no evidence this is seen our analyses between 5 along isentrope....
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn unexpected sulfone to sulfinate transformation. Electrophilic fragmentation-cyclization of diallenic sulfones and propargylic allenesulfinates .alpha.,.beta.-unsaturated .gamma.-sultinesSamuel Braverman David ReismanCite this: J. Am. Chem. Soc. 1977, 99, 2, 605–607Publication Date (Print):January 1, 1977Publication History Published online1 May 2002Published inissue 1 January 1977https://doi.org/10.1021/ja00444a048RIGHTS & PERMISSIONSArticle...
We have performed quasi-isentropic compression experiments on radiation-damaged stainless steel. The samples were dynamically loaded by Sandia National Laboratory’s Z accelerator with a ramp wave. Sample/window interface velocities recorded VISAR. velocity histories suggest sudden volume reduction of the material above 40 kbar caused collapse nanosized voids. This is predicted theoretical model void based emission vacancy-type dislocations loops. compare results these to hydrodynamic...
We report high-pressure dynamic compression experiments of liquid water along a quasiadiabatic path leading to the ice-VII region phase diagram. observe features resembling van der Waals loops and find that is compacted metastable state close ice density before onset crystallization. By analyzing characteristic kinetic time scale involved we estimate nucleation barrier conclude has been compressed its thermodynamic stability limit.
The Hugoniot and critical shear strength of shock-compressed metals can be obtained directly from molecular dynamics simulations without recourse to surface velocity profiles their analyses. Results in aluminum containing an initial distribution microscopic defects are shown agree with experimental results.
We have developed a semianalytic expression for the total energy loss to vacuum transmission-line electrode operated at high lineal current densities. (We define density ${j}_{\ensuremath{\ell}}\ensuremath{\equiv}B/{\ensuremath{\mu}}_{0}$ be per unit width, where $B$ is magnetic field surface and ${\ensuremath{\mu}}_{0}$ permeability of free space.) The accounts due Ohmic heating, diffusion, $\mathbf{j}\ifmmode\times\else\texttimes\fi{}\mathbf{B}$ work, increase in transmission line's...
Many papers have been published on the theory of magnetic insulation and use Zflow analysis magnetically insulated transmission lines (MITLs). We describe herein a novel design process using circuit code SCREAMER for real-world MITL z-pinch loads based model insulation. In particular, we 15-TW, 10-MA, 100-ns double-disk line only modeling tools MITL. Critical issues such as current loss to anode during setup transition from non-emitting vacuum power feed an play large role in design. This...
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...
The 27GPa pressure-induced epsilon–phi phase transition in octahydro-1,3,5,7-tetranitro-l,3,5,7-tetrazocine (HMX) is explored using the isentropic compression experiment (ICE) technique at Sandia National Laboratories Z-machine facility. Our data indicate that this sluggish and if it does occur to any extent under time scales (200–500ns) strain rates (5×105) typical of ICE loading conditions, amount conversion small.
Comparisons of measured total radiated x-ray power from annular wire-array z-pinches with a variety models as function wire number, array mass, and load radius are reviewed. The data, which comprehensive, have provided important insights into the features dynamics that critical for high generation. Collectively, comparisons data model calculations suggest number underlying dynamical mechanisms involving cylindrical asymmetries plasma instabilities contribute to characteristics. For example,...
We observed dynamically driven phase transitions in isentropically compressed bismuth. By changing the stress loading conditions we explored two distinct cases: one which experimental signature of transformation corresponds to phase-boundary crossings initiated at both sample interfaces, and another trace is due a single advancing front bulk material. introduce coupled kinetics - hydrodynamics model that for this second case enables us, under suitable simplifying assumptions, directly...
The Thor pulsed power generator is being developed at Sandia National Laboratories. design consists of up to 288 decoupled and transit time isolated capacitor-switch units, called "bricks," that can be individually triggered achieve a high degree pulse tailoring for magnetically driven isentropic compression experiments (ICE) [D. B. Reisman et al., Phys. Rev. Spec. Top.-Accel. Beams 18, 090401 (2015)]. connecting transmission lines are impedance matched the bricks, allowing capacitor energy...
In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator (Albuquerque, NM) we have revisited a problem first described in detail by Heinz Knoepfel (1970). Unlike the 1-Tesla MITL's of pulsed power accelerators used to produce intense particle beams, Z's disk, transmission line (downstream current addition) is 100-1200-Tesla regime; so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using MHD code MACH2 been...
A novel method for determining the equation-of-state (EOS) along release isentrope in an isochoric (constant volume) heated plasma is presented. This approach demonstrated using simulations of a solid density, 10 eV expanding Al plasma. Determining material EOS data validated to pressures near 80 Mbar, much higher than current isentropic compression experiments allow. Limitations at very high temperature (Te⩾100 eV), due formation radiative conduction layer rarefaction interface, are also discussed.
At Lawrence Livermore National Laboratory we have developed a coupled helical-coaxial FCG device called the Full Function Test (FFT). This was used to deliver 98 MA of current and 66 MJ energy an inductive load. The successful testing FFT represented culmination effort establish high-energy pulsed power program that would greatly exceed performance capacitor bank facilities. Using modeling, design, experimental capabilities for FFT, new generator, Mini-G. Based upon half-scaling device,...