High-resolution laser interferometer for measurement of electron density in transient plasma

1969 ◽  
Vol 5 (17) ◽  
pp. 413 ◽  
Author(s):  
T. Kano ◽  
A.G. Heaton
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Laser Interferometer ◽  
Transient Plasma

Pushing the Envelope

2018 ◽  
Author(s):  
Eaton E. Lattman ◽  
Thomas D. Grant ◽  
Edward H. Snell
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Structural Information ◽  
Hydration Shell ◽  
Three Dimensional ◽  
Scattering Data ◽  
Saxs Data ◽  
Electron Density Function ◽  
Angle Scattering ◽  
Iterative Structure

Direct electron density determination from SAXS data opens up new opportunities. The ability to model density at high resolution and the implicit direct estimation of solvent terms such as the hydration shell may enable high-resolution wide angle scattering data to be used to calculate density when combined with additional structural information. Other diffraction methods that do not measure three-dimensional intensities, such as fiber diffraction, may also be able to take advantage of iterative structure factor retrieval. While the ability to reconstruct electron density ab initio is a major breakthrough in the field of solution scattering, the potential of the technique has yet to be fully uncovered. Additional structural information from techniques such as crystallography, NMR, and electron microscopy and density modification procedures can now be integrated to perform advanced modeling of the electron density function at high resolution, pushing the boundaries of solution scattering further than ever before.

scholarly journals Refinement of proteins at subatomic resolution withMOPRO

2001 ◽  
Vol 34 (2) ◽  
pp. 214-223 ◽  
Author(s):  
Benoit Guillot ◽  
Laurence Viry ◽  
Regis Guillot ◽  
Claude Lecomte ◽  
Christian Jelsch
Keyword(s):  
High Resolution ◽  
Supramolecular Chemistry ◽  
Electron Density ◽  
Structure Factor ◽  
Atomic Electron ◽  
Gradient Algorithm ◽  
Large Structures ◽  
Diagonal Approximation ◽  
Atomic Electron Density ◽  
Very High

Crystallography at subatomic resolution permits the observation and measurement of the non-spherical character of the atomic electron density. Charge density studies are being performed on molecules of increasing size. TheMOPROleast-squares refinement software has thus been developed, by extensive modifications of the programMOLLY, for protein and supramolecular chemistry applications. The computation times are long because of the large number of reflections and the complexity of the multipolar model of the atomic electron density; the structure factor and derivative calculations have thus been parallelized. Stereochemical and dynamical restraints as well as the conjugate gradient algorithm have been implemented. A large number of the normal matrix off-diagonal terms turn out to be very small and the block diagonal approximation is thus particularly efficient in the case of large structures at very high resolution.

Insight into the Electron Density Distribution in an O,N-Heterocyclic Stannylene by High-Resolution X-ray Diffraction Analysis

2019 ◽  
Vol 2019 (6) ◽  
pp. 875-884 ◽  
Author(s):  
Maxim G. Chegerev ◽  
Alexandr V. Piskunov ◽  
Kseniya V. Tsys ◽  
Andrey G. Starikov ◽  
Klaus Jurkschat ◽  
...  
Keyword(s):  
High Resolution ◽  
Density Distribution ◽  
Diffraction Analysis ◽  
Electron Density ◽  
Electron Density Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Insight Into

scholarly journals Thermal History of Matrix Forsterite Grains from Murchison Based on High-resolution Tomography

2021 ◽  
Vol 922 (2) ◽  
pp. 256
Author(s):  
Giulia Perotti ◽  
Henning O. Sørensen ◽  
Henning Haack ◽  
Anja C. Andersen ◽  
Dario Ferreira Sanchez ◽  
...  
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Density Maps ◽  
Thermally Processed ◽  
The Matrix ◽  
History Of ◽  
Chondrule Formation

Abstract Protoplanetary disks are dust- and gas-rich structures surrounding protostars. Depending on the distance from the protostar, this dust is thermally processed to different degrees and accreted to form bodies of varying chemical compositions. The primordial accretion processes occurring in the early protoplanetary disk such as chondrule formation and metal segregation are not well understood. One way to constrain them is to study the morphology and composition of forsteritic grains from the matrix of carbonaceous chondrites. Here, we present high-resolution ptychographic X-ray nanotomography and multimodal chemical microtomography (X-ray diffraction and X-ray fluorescence) to reveal the early history of forsteritic grains extracted from the matrix of the Murchison CM2.5 chondrite. The 3D electron density maps revealed, at unprecedented resolution (64 nm), spherical inclusions containing Fe–Ni, very little silica-rich glass and void caps (i.e., volumes where the electron density is consistent with conditions close to vacuum) trapped in forsterite. The presence of the voids along with the overall composition, petrological textures, and shrinkage calculations is consistent with the grains experiencing one or more heating events with peak temperatures close to the melting point of forsterite (∼2100 K), and subsequently cooled and contracted, in agreement with chondrule-forming conditions.

Transient Light Emissions from a Laser Perturbed Plasma

1972 ◽  
Vol 50 (19) ◽  
pp. 2338-2347 ◽  
Author(s):  
H. A. Baldis ◽  
R. A. Nodwell ◽  
J. Meyer
Keyword(s):  
Laser Pulse ◽  
Electron Density ◽  
Laser Light ◽  
Line Emission ◽  
Argon Plasma ◽  
Stark Broadening ◽  
Excited Atoms ◽  
Electron Density Gradient ◽  
Transient Plasma ◽  
The Continuum

The interaction between a 20 MW Q-switched ruby laser pulse and a partially ionized argon plasma has been studied experimentally. When the focused laser pulse is fired into the plasma, a transient emission from the plasma may be observed both in the continuum and line emission. From measurements of the absolute intensities of this transient radiation, estimates have been made of the population density of the excited atoms and of the electron densities. The Stark broadening of the Ar II lines has also been measured to obtain the electron density in the transient plasma and data obtained in this way are consistent with those obtained from the continuum radiation. During the time when the laser light is incident on the plasma the Ar II lines show a strong asymmetry which disappears quickly after the laser pulse has terminated. This asymmetry can be explained in terms of the electron density gradient present in the expanding perturbed plasma.

Creep rate spectroscopy using a laser interferometer as ultra-high resolution technique for study of relaxations

1997 ◽  
Vol 119 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Nina N. Peschanskaya ◽  
Pavel N. Yakushev ◽  
Alfred B. Sinani ◽  
Vladimir A. Bershtein
Keyword(s):  
High Resolution ◽  
Creep Rate ◽  
Laser Interferometer ◽  
High Resolution Technique

scholarly journals Theoretical Modeling of High-Resolution X-ray Spectra Emitted by Tungsten and Molybdenum Ions from Tokamak Plasmas

2020 ◽  
Vol 39 (5) ◽  
pp. 194-201
Author(s):  
Ł. Syrocki ◽  
K. Słabkowska ◽  
E. Węder ◽  
M. Polasik ◽  
J. Rzadkiewicz
Keyword(s):  
High Temperature ◽  
High Resolution ◽  
Detailed Analysis ◽  
Electron Density ◽  
Wavelength Range ◽  
Tokamak Plasmas ◽  
Temperature Plasma ◽  
X Ray ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to allow the advanced interpretation of the X-ray spectra registered by the high-resolution crystal KX1 spectrometer on the JET with an ITER-like wall, especially to determine how the relative emission contributions of tungsten and molybdenum ions change during a JET discharge, the X-ray spectra have been carefully modeled over a narrow wavelength range. The simulations have been done in the framework of Collisional–Radiative model implemented in Flexible Atomic Code for an electron density (ne = 2.5 × 1019 m−3), and electron temperatures between Te = 3.0 keV and Te = 4.5 keV, typical for JET. Moreover, performed detailed analysis in the framework of the proposed procedure can be useful in determining temperature of a high temperature plasma generated in tokamaks.

scholarly journals Wavelet-based analysis and power law classification of C/NOFS high-resolution electron density data

Radio Science ◽  
2014 ◽  
Vol 49 (8) ◽  
pp. 680-688 ◽  
Author(s):  
C. L. Rino ◽  
C. S. Carrano ◽  
Patrick Roddy
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Power Law ◽  
Density Data ◽  
Resolution Electron

scholarly journals Structure of the poleward wall of the trough and the inclination of the geomagnetic field above the EISCAT radar

1997 ◽  
Vol 15 (6) ◽  
pp. 740-746 ◽  
Author(s):  
D. G. Jones ◽  
I. K. Walker ◽  
L. Kersley
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Time Scale ◽  
Geomagnetic Field ◽  
Energy Input ◽  
Current Model ◽  
Soft Particle ◽  
Dynamic Feature ◽  
Eiscat Radar ◽  
Good Agreement

Abstract. A special high-resolution routine of the EISCAT radar has been used to investigate the structure and development of the poleward wall of a deep trough in electron density. The feature was tracked by the radar during a 7-hour period under very quiet geomagnetic conditions. The field-aligned nature of the structure enabled an estimate to be made of the inclination of the geomagnetic field above EISCAT that was in good agreement with the current model. Observations of narrow field-aligned enhancements in electron temperature demonstrated that the wall of this trough is a dynamic feature, reforming regularly as the electron density responds on a time scale of tens of minutes to energy input from soft-particle precipitation.

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