A5101965828- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Advanced Chemical Physics Studies
- Mass Spectrometry Techniques and Applications
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- High-pressure geophysics and materials
- Theoretical and Computational Physics
- Gas Dynamics and Kinetic Theory
- Solar and Space Plasma Dynamics
- Advanced Frequency and Time Standards
- Microstructure and Mechanical Properties of Steels
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Ionosphere and magnetosphere dynamics
- Spectroscopy and Quantum Chemical Studies
- Magnetic confinement fusion research
- Spectroscopy and Laser Applications
- Metallurgy and Material Forming
- Ion-surface interactions and analysis
- Quantum, superfluid, helium dynamics
- Computational Fluid Dynamics and Aerodynamics
- Rare-earth and actinide compounds
- Metal and Thin Film Mechanics
- Metal Alloys Wear and Properties
Institute of Applied Physics and Computational Mathematics
2005-2024
Northeastern University
2016
By performing quantum molecular dynamics (QMD) simulations, we investigate the equation of states, electrical and optical properties expanded beryllium at densities two to one-hundred lower than normal solid density temperatures ranging from 5000 30000 K. With decreasing Be, response evolves one characteristic a simple metal an atomic fluid. fitting conductivity spectra with Drude-Smith model, it is found that conducting electrons become localized densities. In addition, negative derivative...
Aims. We present results of the electron-impact broadening parameters (i.e., widths and shifts) spectral lines in singly ionized Be II, Sr Ba II ions, calculated by using our relativistic quantum mechanical methods.
Based on a detailed configuration accounting model with the term structures treated by unresolved transition array model, large scale calculation has been performed for opacities of medium- and high-$Z$ materials mixtures. Agreement between our calculated results previous theoretical simulations is obtained. By filling in low-opacity regions one material high-opacity other materials, Rosseland mean opacity their combination will be increased. This should great interest to hohlraum design...
ABSTRACT We report on opacity measurements of a silicon (Si) plasma at temperature (72 ± 5) eV and density (6.0 1.2) mg cm −3 in the photon energy range 1790–1880 eV. A 23 μ g −2 Si foil tamped by 50 CH layers each side was heated to hot-dense state X-ray radiation emitted from D-shaped gold cavity that irradiated intense lasers. Absorption lines 1 s − 2 p transitions xiii ix ions have been measured using point-projection spectroscopy. The transmission spectrum determined comparing light...
Electron–ion recombination of sulfur ions with electrons in the energy range 1.6–3 keV was studied at Stockholm Refrigerated Electron Beam Ion Trap. We obtained KLn dielectronic (DR) cross sections up to n = 5 for H-like and He-like by observing x-rays from trapped ions. A fully relativistic distorted wave approximation method used calculating DR sections, while resonance energies were a multiconfiguration Dirac–Fock approach using GRASP II code. The calculations agree experimental results...
Using quantum molecular dynamics simulations, we show that the electrical and optical properties of fluid iron change dramatically from compressed to expanded regime. Along isochores, main trend resistivity, which is in good agreement with experimental data, found be well reproduced by our calculations. Near low densities, where constant volume derivative resistivity on internal energy becomes negative, transition metallic non-metallic state takes place. The study conductivity, absorption...
In this paper, we present results for the relativistic quantum mechanical calculations of electron-impact line widths and shifts 2p-2s transitions in doubly ionized boron (B III) ions. We use Dirac R-matrix methods to solve (N + 1)-electron colliding systems scattering matrices that are required. The calculated an electron density 1:81 × 1018 cm-3 temperature 10:6 eV. obtained agree well with all semiempirical most semiclassical calculations, closer experimental published by Glenzer Kunze...
The electrical and optical properties of warm dense beryllium along the principal Hugoniot for temperatures from 0.95 eV to 10.65 densities 3.8 6.0 g/cm3 are investigated by using quantum molecular dynamics (QMD) simulations combined with Kubo-Greenwood formulation. dc conductivity σdc ionization fraction yielded fitting Drude-Smith model. first-principles transport coefficients compared results Lee-More model Brysk [Plasma Phys. 17, 473 (1975)]. Compared QMD result, underestimates 87% at...
This paper introduces a theoretical approach for the calculations of spectral line broadening in plasmas. As an example, profiles Stark or are calculated and investigated with this under some interesting plasma conditions. In our calculations, Dirac R-matrix methods used to calculate electron-impact operators, which assumed be diagonal matrix simplify. The standard (Hooper) theory is chosen electric microfield distribution function. Furthermore, population density (bm) ionization state m...
Dielectronic recombination (DR) for highly charged Fe, I, Ba, Bi and U ions are calculated with our developed codes. The calculations based on isolate resonance approximation, the free electrons described a fully relativistic distorted wave. Auger decay rates in Coulomb plus generalized Breit interaction (GBI) Moller interaction, respectively. two-electron integrals imaginary parts of GBI interactions derived to be product two one-electron integrals. By comparing published theoretical...
We present measurements of the 2p-3d transition opacity a hot molybdenum–scandium sample with nearly half-vacant molybdenum M-shell configurations. A plastic-tamped foil is radiatively heated to high temperature in compact D-shaped gold Hohlraum driven by ∼30 kJ laser energy at SG-100 facility. X rays transmitted through and scandium plasmas are diffracted crystals finally recorded image plates. The electron temperatures particular spatial temporal zones determined K-shell absorption plasma....
In this research, ∼0.14-micron-thick aluminum tamped by plastic is heated up to ∼110eV the x-ray pulse from Z-pinch-driven dynamic Hohlraum on an 8-MA machine in China. After ∼6-ns heating stage, higher-energy xrays ∼2-ns- long backlight pass through hot aluminum. The transmission estimated comparing radiation passing sample one shot with only another shot, spectra obtained using elliptically bent concave crystal spectrometer. reveals features corresponding absorption Li-like and a series of...
Based on the nonlocal thermodynamic equilibrium state and large optical thickness of plasma, we establish one-dimensional nonequilibrium radiation-transport equation from diffusion approximation. Through finite volume method, discrete scheme conditions for its definite solution are proposed. The reliability is validated.
We report a systematic method to perform calculations of spectral line broadening parameters in plasmas. This is applied calculate Stark-broadening profiles Pα (n = 4 → n 3) transitions under certain specific plasma conditions, by treating this case as an example. In the framework fully relativistic Dirac R-matrix theory, we electron-impact operators, which are assumed be diagonal matrix simplify situation. The electric microfield distribution function calculated retaining Hooper's...
Using collisional-radiative model codes, we calculate the ionic charge state distributions of Fe plasma produced in a \(Z\)-pinch experiment. The influence dilution factor (i.e., geometrical reduction factor) α on simulated is investigated. With newly diagnosed conditions, involving and electron temperatures, obtained ion ratios Na F as well average \(\langle Z\rangle\) are consistently good agreement with experimental measurements for first time.
We have obtained dielectronic recombination (DR) cross sections for H-like and He-like S, using the Stockholm Refrigerated Electron Beam Ion Trap (R-EBIT). The experimental results are compared with a calculation resonance positions strengths show good agreement within error bars, but also deviations in some cases.
In this article,the emission coefficients and absorption of a Z-pinch Al plasma are calculated in nonlocal- thermodynamic-equilibrium model (NLTE) under detailed level accounting (DLA) base on the calculation populations at first.Then,we calculate detail spectrum analyze opacity effects elementary using simple 1-D slate radicalization-transition model.The results indicate that effect is very strong to especially resonance lines (It influenced figure obviously).Yet it’s slightly satellite...