A5031174936- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Lightning and Electromagnetic Phenomena
- Plasma Diagnostics and Applications
- Electron and X-Ray Spectroscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Ion-surface interactions and analysis
- Advanced MRI Techniques and Applications
- Atomic and Subatomic Physics Research
- Smart Materials for Construction
- Advancements in Photolithography Techniques
- Radiomics and Machine Learning in Medical Imaging
- Combustion and Detonation Processes
- Advanced Optical Sensing Technologies
- Fuel Cells and Related Materials
- Electrical Fault Detection and Protection
- Material Properties and Processing
- Ocular and Laser Science Research
- Advanced Optical Network Technologies
- Rheology and Fluid Dynamics Studies
- Photoacoustic and Ultrasonic Imaging
- Optical Coatings and Gratings
- Welding Techniques and Residual Stresses
Los Alamos National Laboratory
2014-2022
Voss Scientific (United States)
2022
University of Michigan
2021
Computational Physics (United States)
2018
University of Oklahoma
2000
Abstract Electromagnetic pulse (EMP) events produce low‐energy conduction electrons from Compton electron or photoelectron ionizations with air. It is important to understand how interact air in order accurately predict EMP evolution and propagation. An swarm model can be used monitor the time of an environment characterized by electric field pressure. Here a developed that based on coupled ordinary differential equations (ODEs) described Higgins et al. (1973), hereinafter HLO. The ODEs...
Abstract Atmospheric electromagnetic pulse (EMP) events are important physical phenomena that occur through both man‐made and natural processes. Radiation‐induced currents voltages in EMP can couple with electrical systems, such as those found satellites, cause significant damage. Due to the disruptive nature of EMP, it is accurately predict evolution propagation computational models. CHAP‐LA ( C ompton H igh A ltitude P ulse‐ L os lamos) a state‐of‐the‐art code solves Maxwell s equations...
Cu foils, $200\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{m}$ in thickness, were heated two stages by a $\ensuremath{\sim}100$-ns-long monoenergetic electron bunch at 19.8 MeV and current of 1.7 kA ($8.5\ifmmode\times\else\texttimes\fi{}{10}^{14} {e}^{\ensuremath{-}}$) 2-mm-spot to ${T}_{e}\ensuremath{\sim}1$ eV. After 45 ns isochoric heating, the pressure foil builds up $>20$ GPa (200 kbar), it begins hydrodynamically disassemble, velocity spread is measured. Near end pulse, 1550 nm...
During the Summer and Fall of 1998 we launched five balloon‐borne instruments into thunderstorms to observe changes in vertical component electric field caused by lightning. Four these were for measurement change only. The fifth was part a larger package that included gamma radiation detector GPS receiver on board. We have processed electric‐field‐change data from two flights. discuss examples observed at altitude compare them with National Lightning Detection Network (NLDN) cloud‐to‐ground...
Motivation: This abstract focuses on educating how high-gradient MRI systems can utilize the multi-echo functional (ME-fMRI) techniques. Goal(s): We explain blood-oxygen-level-dependent (BOLD) signal technique and additional echoes improve fidelity. Approach: The ME-fMRI, using three or more allow for pixelwise T2* decay to be modeled, as BOLD contrast is a function of evolution over time, an experiment sampling voxel-wise used separate from artifact constituents. Results: Gradient with...
Spatially and temporally resolved visible absorption spectroscopy is performed on sodium D-lines present as surface contaminants an expanded dense aluminum plasma plume. An 80-ns FWHM, intense, relativistic electron beam deposits 5.4 J into a 100-μm-thick Al foil, which isochorically heats subsequently hydrodynamically expands the material through warm matter state classical-like state, with coupling parameter of approximately 0.2 degeneracy 270. The Na contamination, carried along expanding...
This paper reports on synthetic transmission results from Lasnex [Zimmerman and Kruer, Comments Plasma Phys. 2, 51 (1975)] radiation-hydrodynamics simulations of opacity experiments carried out at Sandia National Laboratories' recently upgraded ZR facility. The focus is utilizing disk targets composed a half-moon Fe/Mg mixture tamped either end with 10-μm CH an additional 35-μm beryllium tamper accessory the facing spectrometer. Five x-ray sources peak power ranging 10 to 24 TW were used in...
Abstract We have developed a general, three‐dimensional method to locate sources of earth‐directed radiation that takes into account the flight paths reflected signals. While time‐of‐arrival algorithms exist for locating radio using line‐of‐sight propagation paths, originating above surface Earth will not necessarily emit strong power along direct satellites. A combination and ground‐reflected pulses or only signals from such could be received by satellite‐borne sensors. The work presented...
A spatially resolved air-wedge shearing interferometer and shadowgraph diagnostic provides measurements of electron density with a resolution ∼40 μm. ∼100-ns-long, monoenergetic bunch at 19.8 MeV current 1.4 kA (8.5×1014 e−) heats 100-μm-thick aluminum (Al) foils in 1-mm-spot to Te∼1 eV. 5-ns-long, ∼60 mJ, frequency doubled Nd:YAG laser probes the dense Al plasma. Electron densities up 1020cm−3 are resolved; maximum resolvable is limited by opacity, transmission, spatial fringe achievable...