A5078250215- Laser-Plasma Interactions and Diagnostics
- Magnetic confinement fusion research
- Nuclear reactor physics and engineering
- Nuclear and radioactivity studies
- Nuclear Physics and Applications
- Nuclear Materials and Properties
- Pulsed Power Technology Applications
- High-pressure geophysics and materials
- Laser-induced spectroscopy and plasma
- Cosmology and Gravitation Theories
- Radioactive contamination and transfer
- Galaxies: Formation, Evolution, Phenomena
- Atmospheric and Environmental Gas Dynamics
- Big Data Technologies and Applications
- Graphite, nuclear technology, radiation studies
- Magnetic Field Sensors Techniques
- Electromagnetic Launch and Propulsion Technology
- Radioactive element chemistry and processing
- Nuclear Issues and Defense
- Particle accelerators and beam dynamics
- Scientific Research and Discoveries
- Statistical and numerical algorithms
- Radio Astronomy Observations and Technology
- Solar and Space Plasma Dynamics
- Radioactivity and Radon Measurements
Los Alamos National Laboratory
1997-2018
Sandia National Laboratories
2008-2018
Sandia National Laboratories California
2012-2013
Cornell University
1992
We construct an improved version of nonrelativistic QCD for use in lattice simulations heavy quark physics, with the goal reducing systematic errors from all sources to below 10\%. develop power counting rules assess importance various operators action and compute leading order corrections required by relativity finite spacing. discuss radiative tree level coupling constants, presenting a procedure that effectively resums largest such orders perturbation theory. Finally, we comment on size...
The first controlled experiments measuring the growth of magneto-Rayleigh-Taylor instability in fast (∼100 ns) Z-pinch plasmas are reported. Sinusoidal perturbations on surface an initially solid Al tube (liner) with wavelengths 25-400 μm were used to seed instability. Radiographs 15 resolution captured evolution outer liner surface. Comparisons numerical radiation magnetohydrodynamic simulations show remarkably good agreement down 50 wavelengths.
High current pulsed-power generators efficiently store and deliver magnetic energy to z-pinch targets. We review applications of magnetically driven implosions (MDIs) inertial confinement fusion. Previous research on MDIs wire-array z-pinches for radiation-driven indirect-drive target designs is summarized. Indirect-drive are compared with new targets that imploded by direct application pressure produced the pulse. describe design elements such as larger absorbed energy, magnetized...
Novel experimental data are reported that reveal helical instability formation on imploding $z$-pinch liners premagnetized with an axial field. Such instabilities differ dramatically from the mostly azimuthally symmetric form unmagnetized liners. The structure persists at nearly constant pitch as liner implodes. This is surprising since, surface, azimuthal drive field presumably dwarfs for all but earliest stages of experiment. These fundamentally 3D results provide a unique and challenging...
This paper explores the role of electro-thermal instabilities on dynamics magnetically accelerated implosion systems. Electro-thermal result from non-uniform heating due to temperature dependence in conductivity a material. Comparatively little is known about these types compared well Magneto-Rayleigh-Taylor (MRT) instability. We present simulations that show electrothermal form immediately after surface material conductor melts and can act as significant seed subsequent MRT instability...
The implosions of initially solid beryllium liners (tubes) have been imaged with penetrating radiography through to stagnation. These novel radiographic data reveal a high degree azimuthal correlation in the evolving magneto-Rayleigh-Taylor structure at times just prior (and during) stagnation, providing stringent constraints on simulation tools used by broader energy density physics and inertial confinement fusion communities. To emphasize this point, comparisons 2D 3D radiation...
Several cosmological measurements have attained significant levels of maturity and accuracy over the past decade. Continuing this trend, future observations promise cosmic mass distribution at an level 1% out to spatial scales with $k\ensuremath{\sim}10h\text{ }\text{ }{\mathrm{Mpc}}^{\ensuremath{-}1}$ even smaller, entering highly nonlinear regimes gravitational instability. In order interpret these extract useful information from them, such as equation state dark energy, very costly high...
A recent publication [D. B. Sinars et al., Phys. Rev. Lett. 105, 185001 (2010)] describes the first controlled experiments measuring growth of magneto-Rayleigh–Taylor instability in fast (∼100 ns) Z-pinch plasmas formed from initially solid aluminum tubes (liners). Sinusoidal perturbations on surface these liners with wavelengths 25–400 μm were used to seed single-mode instabilities. The evolution outer liner was captured using multiframe 6.151 keV radiography. initial paper shows that there...
Recent experiments on Sandia's Z facility have confirmed simulation predictions of dramatically reduced instability growth in solid metallic rods when thick dielectric coatings are used to mitigate density perturbations arising from an electrothermal instability. These results provide further evidence that the inherent surface roughness as a result target fabrication is not dominant seed for magneto-Rayleigh-Taylor instabilities liners with carefully machined smooth surfaces, but rather form...
The complexity and accuracy of current future "precision cosmology" observational campaigns has made it essential to develop an efficient technique for directly combining simulation data sets determine cosmological model parameters, a procedure we term "calibration." Once satisfactory calibration the underlying is achieved, independent predictions new observations become possible. For this be effective, robust characterization uncertainty in process highly desirable. In Letter describe...
A recent publication [K. J. Peterson et al., Phys. Plasmas 19, 092701 (2012)] describes simulations and experiments of electrothermal instability growth on well characterized initially solid aluminum copper rods driven with a 20 MA, 100 ns rise time current pulse Sandia National Laboratories Z accelerator. Quantitative analysis the high precision radiography data obtained in showed excellent agreement demonstrated levels dense matter that could not be explained by magneto-Rayleigh-Taylor...
In this paper, we explore magnetized liner inertial fusion (MagLIF) [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] using a semi-analytic model [R. D. McBride and S. Slutz, 22, 052708 (2015)]. Specifically, present simulation results from that: (a) illustrate the parameter space, energetics, overall system efficiencies of MagLIF; (b) demonstrate dependence radiative loss rates on radial fraction fuel that is preheated; (c) some recent experimental MagLIF program at Sandia National...
We describe an approximate statistical model for the sample variance distribution of nonlinear matter power spectrum that can be calibrated from limited numbers simulations. Our retains common assumption a multivariate normal band powers but takes full account (parameter-dependent) covariance. The is using extension framework in Habib et al. (2007) to train Gaussian processes mean and covariance given set simulation runs over hypercube parameter space. demonstrate performance this machinery...
This is an expository paper. Here we propose a decision-theoretic framework for addressing aspects of the confidentiality information problems in publicly released data. Our basic premise that problem needs to be conceptualized by looking at actions three agents: data collector, legitimate user, and intruder. aim prescribe first agent who desires provide useful second agent, but must protect against possible misuse third. The under constraint has public all; this some societies may not case....
This paper uses elementary techniques drawn from renormalization theory to derive the Lorentz-Dirac equation for relativistic classical electron Maxwell-Lorentz equations a charged particle coupled electromagnetic field. I show that resulting effective theory, valid motions change over distances large compared radius, reduces naturally Landau-Lifshitz equation. No familiarity with or quantum field is assumed.
Environmental monitoring of nuclear activities promises to play a large role in the improvements international safeguards under International Atomic Energy Agency's Programme 93+2. Monitoring stable noble‐gas (Kr, Xe) isotopic abundances at reprocessing plant stacks appears be able yield information on burnup and type fuel being processed. To estimate size these signals, model calculations production Kr Xe nuclides reactor subsequent dilution stack are carried out for two case studies: PWR...
Summary form only given. This paper concentrates on the effects of cylindrical geometry magneto-Rayleigh-Taylor instability (MRT), a major concern in magnetized liner inertial fusion concept (MagLIF) [1]. Several issues are being studied, such as Bell-Plesset effect [2], magnetic shear and feedthrough [3], nonzero MRT growth rate that remains (but was hardly noticed) k = m 0 limit Harris' seminal [4], where respectively azimuthal axial wavenumber. In implosions, those for MagLIF, significant...
Summary form only given. We have developed conceptual designs of two next-generation petawatt-class pulsed-power accelerators. The are based on the architecture described in Ref. [1]. prime power source both is a system lineartransformer drivers (LTDs) [2,3]. Both use six water-insulated radial-transmission-line impedance transformers [1,4,5] to transport generated by LTDs six-level vacuum-insulator stack. stack connected radial magnetically insulated transmission lines (MITLs); MITLs joined...
Click to increase image sizeClick decrease size Notes The author is grateful Joseph Pilat, William Stanbro, Chad Olinger, and John Puckett of Los Alamos for stimulating discussions on this related topics.