A5054613611- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Laser-Matter Interactions and Applications
- Laser Design and Applications
- Atomic and Molecular Physics
- Plasma Applications and Diagnostics
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Laser Material Processing Techniques
- Electrohydrodynamics and Fluid Dynamics
- Quantum Electrodynamics and Casimir Effect
- Advanced Chemical Physics Studies
- Diamond and Carbon-based Materials Research
- Metal and Thin Film Mechanics
- Mass Spectrometry Techniques and Applications
- Spectroscopy and Laser Applications
- Gas Dynamics and Kinetic Theory
- Quantum Mechanics and Applications
- Dust and Plasma Wave Phenomena
- Vacuum and Plasma Arcs
- Advanced X-ray Imaging Techniques
- Quantum, superfluid, helium dynamics
- Catalytic Processes in Materials Science
- Magnetic confinement fusion research
Naval Research Laboratory Plasma Physics Division
2013-2024
United States Naval Research Laboratory
2015-2024
Klinikum Dortmund
2023
Medical University Pleven
2018
Instituto Tecnológico de Aeronáutica
2018
National University of Science and Technology
2016
Optical Sciences (United States)
2016
University of Michigan–Ann Arbor
2016
University of California, San Diego
2016
Institute for Nuclear Research and Nuclear Energy
2014
We report the results of second charged-particle transport coefficient code comparison workshop, which was held in Livermore, California on 24–27 July 2023. This workshop gathered theoretical, computational, and experimental scientists to assess state computational techniques for understanding coefficients relevant high-energy-density plasma science. Data electronic ionic coefficients, namely, direct current electrical conductivity, electron thermal ion shear viscosity, conductivity were...
The generation of high-energy neutrons using laser-accelerated ions is demonstrated experimentally the Titan laser with 360 J energy in a 9 ps pulse. In this technique, short-pulse, accelerates deuterons from CD2 foil. These are incident on LiF foil and subsequently create high through 7Li(d,xn) nuclear reaction (Q = 15 MeV). Radiochromic film Thomson parabola ion-spectrometer were used to diagnose accelerated protons. Conversion efficiency into protons was 0.5%, an order magnitude greater...
The Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma. Unlike conventional discharges produced by electric fields (DC, RF, microwave, etc.), ionization is driven high-energy (∼ few keV) beam, approach that can be attractive to atomic layer applications. In particular, high densities (1010- 1011 cm−3) in beam generated plasmas, where the temperature remains between 0.3 and 1.0 eV. Accordingly, large flux of ions delivered substrate...
Short pulse laser interactions at intensities of 2×10(21) W cm(-2) with ultrahigh contrast (10(-15)) on submicrometer silicon nitride foils were studied experimentally by using linear and circular polarizations normal incidence. It was observed that, as the target decreases in thickness, electron heating begins to occur for polarization leading sheath acceleration contaminant ions, while thicker targets no or is observed. For polarization, all showed exponential energy spreads similar...
We compare a variety of models used for the calculation transport coefficients in dense plasmas, including average-atom models, based on kinetic theory, structure matching effective potentials, and pair-potential molecular dynamics. In particular, we focus parameter space investigated second charged-particle coefficient code comparison workshop [Stanek et al., Phys. Plasmas 31, 052104 (2024)]. Each model is self-consistent output our calculations. Ionic properties are generated from implicit...
Laser-driven d(d, n)-3He beam-target fusion neutron production from bulk deuterated plastic (CD) targets is compared with a pitcher-catcher target scheme using an identical laser and detector arrangement. For intensities in the range of (1–3) × 1019 W cm−2, it was found that produced high yield (5 104 neutrons per steradian) beamed preferentially propagation direction. Numerical modeling shows importance considering temperature adjusted stopping powers to correctly model production. The CD...
Experiments at the HERCULES laser facility have produced directional neutron beams with energies up to 16.8(±0.3) MeV using d12(d,n)23He,Li73(p,n)47Be,andLi37(d,n)48Be reactions. Efficient Li12(d,n)48Be reactions required selective acceleration of deuterons through introduction a deuterated plastic or cryogenically frozen D2O layer on surface thin film target. The measured yield was ≤1.0 (±0.5)×107 neutrons/sr flux 6.2(±3.7) times higher in forward direction than 90°. This demonstrates that...
This paper, the first in a series of two, presents experimental results demonstrating control electron and ion energy distribution functions beam generated processing plasmas by adding trace concentrations N2 to an Ar background. Measurements function, f0(E), are performed using Langmuir probe while measurements function energy-resolved mass spectrometer. The agree with modeling results, described part II this work, which indicate that inelastic collisions nitrogen molecules provide sink can...
In a novel experiment that images the momentum distribution of individual, isolated 100-nm-scale plasmas, we make first experimental observation shock waves in nanoplasmas. We demonstrate introduction heating pulse prior to main laser increases intensity wave, producing strong burst quasi-monochromatic ions with an energy spread less than 15%. Numerical hydrodynamic calculations confirm appearance accelerating waves, and provide mechanism for generation control these waves. This distinct...
Theoretical study of heavy ion acceleration from sub-micron gold foils irradiated by a short pulse laser is presented. Using two dimensional particle-in-cell simulations, the time history examined in order to get insight into energy deposition and process. For pulses with intensity 3×1021 W/cm2, duration 32 fs, focal spot size 5 μm, 27 J, calculated reflection, transmission, coupling coefficients 20 nm foil are 80%, 5%, 15%, respectively. The conversion efficiency ions 8%. Two highly...
The constriction of the positive column a dc glow discharge in argon at high pressures is analyzed using continuity equations for charged particles and gas thermal balance equation coupled with local electron Boltzmann detailed collisional-radiative model atomic ionic species. Contrary to other existing models inert gas, present self-consistent fully detailed, provides quantitative description all properties. numerical techniques used solve boundary value problem corresponding our set are...
The interaction of intense ultra-short laser pulses with dielectrics is studied theoretically using a one-dimensional simulation model. curl Maxwell's equations are solved coupled to the electron continuity, momentum and energy equations. What new innovative in our approach application 'forest fire' method describe optical field ionization. cumulative action applied holes dielectric, created during ionization events, enhances rate by orders magnitude speeding up avalanche development early...
We make direct observations of localized light absorption in a single nanostructure irradiated by strong femtosecond laser field, developing and applying technique that we refer to as plasma explosion imaging. By imaging the photoion momentum distribution resulting from formation laser-irradiated nanostructure, map spatial location highly thereby image nanoscale absorption. Our method probes individual, isolated nanoparticles vacuum, which allows us observe how small variations composition,...
The effect of nitrogen addition on the emission intensities brightest argon lines produced in a low pressure argon/nitrogen electron beam-generated plasmas is characterized using optical spectroscopy. In particular, decrease 811.5 nm and 763.5 observed, while intensity 750.4 line remains unchanged as added. To explain this phenomenon, non-equilibrium collisional-radiative model developed used to compute population excited states function gas composition. results show that modifies energy...
We report on improved proton acceleration from the interaction of a short pulse high intensity laser (>1020 Wcm−2) with nano-engineered targets. Planar targets (from 7 to 20 μm) protruding gold nanowires having different total areal densities, lengths, and diameters, ranging 3% 60% size focal spot were used during an experimental campaign at 3 J, 30 fs HERCULES facility. The results show importance average number per spot, N, energy absorption. that is significantly by using 1 spot. Detailed...
Numerical simulations of neutron production from deuterium–lithium nuclear fusion reactions have been performed. A set differential cross sections for the 7Li(d,xn) reaction incident deuteron energies up to 50 MeV is assembled. The angular distribution neutrons a thick lithium target simulated and benchmarked against experimental data. Two-stage laser–target experiments has studied as function laser intensity energy. During first stage well collimated beam generated using high-intensity...
In this work, the second in a series of two, spatially averaged model an electron beam generated Ar–N2 plasma is developed to identify processes behind measured influence trace amounts N2 on development energy distribution function. The based numerical solution Boltzmann equation self-consistently coupled set rate balance equations for electrons, argon and nitrogen species. Like experiments, calculations cover only low-energy portion (<50 eV) distribution, therefore source term added...
By using temporal pulse shaping of high-contrast, short laser interactions with solid density targets at intensities $2\ifmmode\times\else\texttimes\fi{}{10}^{21}\text{ }\text{ }\mathrm{W}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$ a 45\ifmmode^\circ\else\textdegree\fi{} incident angle, we show that it is possible to reproducibly generate quasimonoenergetic proton and ion energy spectra. The presence prepulse 33 ps prior the main produced spectra an spread between 25% 60%...
The conditions for generating light ions (Li3+, Be4+, C6+ and Al13+) that have suitable energy deposition the fast ignition of fusion targets via interaction an intense ultrashort pulse laser with thin (converters) are investigated theoretically. converter parameters estimated assuming monoenergetic a one-dimensional parallel plane geometry. Laser densities 3–20 J µm−2 focused onto spot radius 30–100 µm required to attain necessary kinetic energies 10–50 MeV/nucleon, depending on type ion....
Magnetically confined argon plasma in a long cylindrical tube driven by an electron beam is studied experimentally and theoretically. Langmuir probes are used to measure the energy distribution function, density temperature plasmas generated 2 keV, 10 mA beams 25 mTorr background for magnetic field strengths of up 200 Gauss. The experimental results agree with simulations done using spatially averaged Boltzmann model adapted treat immersed constant field. confining effect theoretically fluid...
Electron beam generated plasmas are generally characterized by a high plasma density (&gt;1010 cm−3), and very low electron temperatures (&lt;1 eV), making them well-suited for next generation processing techniques where fluxes of energy ions desirable. In addition, both modeling optical emission spectroscopy indicate relatively concentrations atomic radicals compared to discharges. Due their relevance industrial etching applications, this work focuses on the characteristics produced...
The dynamics of Xe clusters with initial radius between 10 and 100 Å irradiated by an IR subpicosecond laser pulse is investigated. evolution the cluster modeled a relativistic time-dependent three-dimensional particle simulation model. focus this investigation to understand energy absorption how absorbed distributed among various degrees freedom. consequence on energy, average charge per atom, mean electron ion energies, ionization, removal electrons from cluster, expansion was studied....
The angular distribution of neutrons formed in nuclear fusion reactions a high-energy deuteron beam with deuterated polyethylene (CD2) was investigated Monte Carlo ion beam–target deposition model. initial conditions were obtained from two-dimensional particle-in-cell laser–target neutron yield and its studied as function peak laser intensity, pulse duration primary target thickness. proposed scheme for production delivers typical 10−5–10−3 neutrons/ion 105–107 J−1 energy.