scholarly journals Main spectral features of meteors studied using a terawatt-class high-power laser

2019 ◽  
Vol 630 ◽  
pp. A127 ◽  
Author(s):  
M. Ferus ◽  
P. Kubelík ◽  
L. Petera ◽  
L. Lenža ◽  
J. Koukal ◽  
...  
Keyword(s):  
Experimental Data ◽  
Spectral Analysis ◽  
High Resolution ◽  
High Power ◽  
Laser System ◽  
Emission Spectra ◽  
Spectral Lines ◽  
Spectral Features ◽  
Low Resolution ◽  
Meteor Plasma

Context. Meteor spectra are commonly interpreted using data from databases and tables. Several studies have demonstrated very sophisticated calculations of elemental compositions of meteoroid bodies based on the computation of synthetic meteor spectra or on the spectral analysis of airglow plasma containing evaporated, atomized, and ionized meteoroid matter. However, considering accuracy, reliability of computations, lack of laboratory experimental data in this field, as well as the complicated physical structure of meteor plasma, such qualitative assignment or quantitative calculations are still extensively discussed in the scientific community. Even on the laboratory level, many studies have shown the high complexity of the acquisition and interpretation of the data that are recorded with techniques of emission spectroscopy that are in fashion and philosophy similar to the spectral analysis of meteor plasma, that is, detection and quantification of the elements that are ablated from complicated multicomponent matrices. Aims. The current study is focused on the application of terawatt-class laser-induced breakdown spectroscopy (TC-LIBS) of real samples of chondritic meteorites. We recorded emission spectra with high resolution and high precision that contain spectral lines that are typical for real meteoric spectra. Experimental data were compiled in a form that is convenient for the meteoric spectra interpretation and calibration. Methods. TC-LIBS was carried out by a high-power terawatt-class laser facility, the Prague Asterix Laser System (PALS). The spectra were simultaneously recorded by an echelle high-resolution spectrograph in the UV/VIS spectral ranges and by a low-resolution spectrograph that was used for real observation of meteor spectra. We also present calculated synthetic spectra based on data from the NIST atomic spectra database. Results. We assembled etalon qualitative tables of major meteoric spectral features that can be used both for the spectral wavelength calibration of low-resolution observational instruments and for the exact interpretation of meteor spectra. The data are compared with real meteor spectra.

scholarly journals High resolution X-ray emission spectra from picosecond laser irradiated Ge targets

2007 ◽  
Vol 25 (2) ◽  
pp. 245-252 ◽  
Author(s):  
J. Abdallah ◽  
D. Batani ◽  
T. Desai ◽  
G. Lucchini ◽  
A. Faenov ◽  
...  
Keyword(s):  
High Resolution ◽  
Laser System ◽  
Wavelength Region ◽  
Emission Spectra ◽  
Picosecond Laser ◽  
High Repetition Rate ◽  
Spectral Lines ◽  
X Ray ◽  
High Bulk ◽  
Better Than

Investigations of a high resolution X-ray emission spectrum in the range 0.66–0.75 nm obtained by irradiating a Germanium target with high-power p-polarized, 40 picosecond laser radiation at 532 nm wavelength was done. Spectra in the wavelength region of 2l-4l′ and 2l-5l′ L-shell transitions in F-like, Ne-like and Na-like germanium ions were recorded using the FSSR-2D spectrometer equipped with a spherically bent quartz crystal with a spectral resolution λ/Δλ better than 5000. Spectral lines were compared with theoretical values obtained using the LANL plasma kinetic code ATOMIC. Fair agreement between experimental and theoretical spectral lines has been observed, which allowed to measure enough high bulk electron temperature values of 560 eV and electron density of ∼1021 cm−3 in Ge plasma irradiated by rather small commercial high repetition rate Nd:YAG laser system.

scholarly journals petitRADTRANS

2019 ◽  
Vol 627 ◽  
pp. A67 ◽  
Author(s):  
P. Mollière ◽  
J. P. Wardenier ◽  
R. van Boekel ◽  
Th. Henning ◽  
K. Molaverdikhani ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Constants ◽  
Emission Spectra ◽  
Transmission Spectra ◽  
Low Resolution ◽  
Cloud Particle ◽  
Hot Jupiters ◽  
Higher Temperature ◽  
Python Package

We present the easy-to-use, publicly available, Python package petitRADTRANS, built for the spectral characterization of exoplanet atmospheres. The code is fast, accurate, and versatile; it can calculate both transmission and emission spectra within a few seconds at low resolution (λ/Δλ = 1000; correlated-k method) and high resolution (λ/Δλ = 106; line-by-line method), using only a few lines of input instruction. The somewhat slower, correlated-k method is used at low resolution because it is more accurate than methods such as opacity sampling. Clouds can be included and treated using wavelength-dependent power law opacities, or by using optical constants of real condensates, specifying either the cloud particle size, or the atmospheric mixing and particle settling strength. Opacities of amorphous or crystalline, spherical or irregularly-shaped cloud particles are available. The line opacity database spans temperatures between 80 and 3000 K, allowing to model fluxes of objects such as terrestrial planets, super-Earths, Neptunes, or hot Jupiters, if their atmospheres are hydrogen-dominated. Higher temperature points and species will be added in the future, allowing to also model the class of ultra hot-Jupiters, with equilibrium temperatures Teq ≳ 2000 K. Radiative transfer results were tested by cross-verifying the low- and high-resolution implementation of petitRADTRANS, and benchmarked with the petitCODE, which itself is also benchmarked to the ATMO and Exo-REM codes. We successfully carried out test retrievals of synthetic JWST emission and transmission spectra (for the hot Jupiter TrES-4b, which has a Teq of ∼1800 K).

Energy distributions of representative stars in the wavelength region 5000–10 800Å

1966 ◽  
Vol 24 ◽  
pp. 141-154
Author(s):  
D. H. P. Jones
Keyword(s):  
High Resolution ◽  
Wavelength Region ◽  
Spectral Features ◽  
Spectral Classification ◽  
Low Resolution ◽  
Energy Distributions ◽  
The Relationship ◽  
The Continuum

1. The relationship between spectral classification and multi-colour photometry is that between high resolution with low photometric accuracy and low resolution with high photometric accuracy. Observations with a spectrum scanner are one method of bridging the gap. The continuum can be measured in regions comparatively free from lines, especially in the red; moreover the stronger spectral features can be measured quantitatively.

scholarly journals Bright, point X-ray source based on a commercial portable 40 ps Nd:YAG laser system

2004 ◽  
Vol 22 (3) ◽  
pp. 373-379 ◽  
Author(s):  
ANATOLY FAENOV ◽  
TATIANA PIKUZ ◽  
ALEXANDER MAGUNOV ◽  
DIMITRI BATANI ◽  
GIANNI LUCCHINI ◽  
...  
Keyword(s):  
High Resolution ◽  
Nd:Yag Laser ◽  
Laser System ◽  
Experimental Results ◽  
Bright Point ◽  
Low Resolution ◽  
X Ray

We present some experimental results on X-ray spectra obtained from plasmas produced using a compact Nd:YAG laser system. The beam was focused on different targets (Cu, Al, Ge,…) and both high resolution and low resolution X-ray spectra were recorded.

scholarly journals Low Resolution Rotational Spectra of Phenol

2018 ◽  
Vol 10 (6) ◽  
pp. 77
Author(s):  
Ch. O. Qajar ◽  
S. B. Kazymova ◽  
M. R. Menzeleyev ◽  
A. S. Gasanova
Keyword(s):  
High Resolution ◽  
Spectral Data ◽  
Spectral Lines ◽  
Low Resolution ◽  
Rotational Spectra ◽  
Microwave Spectra ◽  
Absorption Level

The modeling of low-resolution (LR) microwave spectra of phenol C6H5OH molecule has been provided in the frequency regions of 0-700 GHz basing on high-resolution (HR) microwave spectral data. The frequency ranges of most intensive absorption level of low-resolution microwave spectra determined. The most intensive spectral lines forming spectra extremums are developed. The recommendations related to perspectives of practical use of achieved results are given.

scholarly journals Modeling the High-resolution Emission Spectra of Clear and Cloudy Nontransiting Hot Jupiters

2021 ◽  
Vol 923 (1) ◽  
pp. 62
Author(s):  
Isaac Malsky ◽  
Emily Rauscher ◽  
Eliza M.-R. Kempton ◽  
Michael Roman ◽  
Deryl Long ◽  
...  
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Emission Spectra ◽  
Spectral Lines ◽  
Orbital Inclination ◽  
Hot Jupiters ◽  
Cloud Coverage ◽  
Doppler Shifts ◽  
Dimensional Models ◽  
Three Dimensional Models

Abstract The advent of high-resolution spectroscopy (R ≳ 25,000) as a method for characterization of exoplanet atmospheres has expanded our capability to study nontransiting planets, vastly increasing the number of planets accessible for observation. Many of the most favorable targets for atmospheric characterization are hot Jupiters, where we expect large spatial variation in physical conditions such as temperature, wind speed, and cloud coverage, making viewing geometry important. Three-dimensional models have generally simulated observational properties of hot Jupiters assuming edge-on viewing, which can be compared to observations of transiting planets, but neglected the large fraction of planets without nearly edge-on orbits. As the first investigation of how orbital inclination manifests in high-resolution emission spectra from three-dimensional models, we use a general circulation model to simulate the atmospheric structure of Upsilon Andromedae b, a typical nontransiting hot Jupiter with high observational interest, due the brightness of its host star. We compare models with and without clouds, and find that cloud coverage intensifies spatial variations by making colder regions dimmer and relatedly enhancing emission from the clear, hotter regions. This increases both the net Doppler shifts and the variation of the continuum flux amplitude over the course of the planet’s orbit. In order to accurately capture scattering from clouds, we implement a generalized two-stream radiative transfer routine for inhomogeneous multiple scattering atmospheres. As orbital inclination decreases, four key features of the high-resolution emission spectra also decrease in both the clear and cloudy models: (1) the average continuum flux level, (2) the amplitude of the variation in continuum with orbital phase, (3) net Doppler shifts of spectral lines, and (4) Doppler broadening in the spectra. Models capable of treating inhomogeneous cloud coverage and different viewing geometries are critical in understanding results from high-resolution emission spectra, enabling an additional avenue to investigate these extreme atmospheres.

scholarly journals Laser-produced plasma-wall interaction

2009 ◽  
Vol 27 (4) ◽  
pp. 725-731 ◽  
Author(s):  
O. Renner ◽  
R. Liska ◽  
F.B. Rosmej
Keyword(s):  
High Resolution ◽  
Laser System ◽  
Emission Spectra ◽  
Plasma Jets ◽  
Research Centre ◽  
High Dispersion ◽  
X Ray ◽  
Hot Plasma ◽  
Laser Produced Plasma ◽  
Wall Interaction

AbstractJets of laser–generated plasma represent a flexible and well-defined model environment for investigation of plasma interactions with solid surfaces (walls). The pilot experiments carried out on the iodine laser system (5–200 J, 0.44 µm, 0.25–0.3 ns, <1×1016 W/cm2) at the PALS Research Centre in Prague are reported. Modification of macroscopic characteristics of the Al plasma jets produced at laser-irradiated double-foil Al/Mg targets is studied by high-resolution, high-dispersion X-ray spectroscopy. The spatially variable, complex satellite structure observed in emission spectra of the Al Lyα group proves a formation of rather cold dense plasma at the laser-exploded Al foil, an occurrence of the hot plasma between both foils and subsequent thermalization, deceleration and trapping of Al ions in the colliding plasma close to the Mg foil surface. The spectra interpretation based on the collisional-radiative code is complemented by 1D and 2D hydrodynamic modeling of the plasma expansion and interaction of counter-propagating Al/Mg plasmas. The obtained results demonstrate a potential of high resolution X-ray diagnostics in investigation of the laser-produced plasma–wall interactions.

scholarly journals IR spectral analysis for the diagnostics of crust earthquake precursors

2012 ◽  
Vol 12 (11) ◽  
pp. 3269-3274 ◽  
Author(s):  
R. M. Umarkhodgaev ◽  
V. A. Liperovsky ◽  
V. V. Mikhailin ◽  
V. V. Bogdanov ◽  
C.-V. Meister ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Electric Field ◽  
Ir Spectrum ◽  
Emission Spectra ◽  
Earthquake Precursors ◽  
Spectral Lines ◽  
Acceleration Process ◽  
Physical Processes ◽  
Electrical Field ◽  
Transparency Region

Abstract. Some possible physical processes are analysed that cause, under the condition of additional ionisation in a pre-breakdown electric field, emissions in the infrared (IR) interval. The atmospheric transparency region of the IR spectrum at wavelengths of 7–15 μm is taken into account. This transparency region corresponds to spectral lines of small atmospheric constituents like CH4, CO2, N2O, NO2, NO, and O3. The possible intensities of the IR emissions observable in laboratories and in nature are estimated. The acceleration process of the electrons in the pre-breakdown electrical field before its adhesion to the molecules is analyzed. For daytime conditions, modifications of the adsorption spectra of the scattered solar emissions are studied; for nighttime, variations of emission spectra may be used for the analysis.

scholarly journals Programming new geometry restraints: parallelity of atomic groups

2015 ◽  
Vol 48 (4) ◽  
pp. 1130-1141 ◽  
Author(s):  
Oleg V. Sobolev ◽  
Pavel V. Afonine ◽  
Paul D. Adams ◽  
Alexandre Urzhumtsev
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
High Resolution ◽  
Structural Biology ◽  
Data Structures ◽  
A Priori ◽  
Low Resolution ◽  
Cryo Electron Microscopy ◽  
Model Geometry ◽  
Associated Data

Improvements in structural biology methods, in particular crystallography and cryo-electron microscopy, have created an increased demand for the refinement of atomic models against low-resolution experimental data. One way to compensate for the lack of high-resolution experimental data is to usea prioriinformation about model geometry that can be utilized in refinement in the form of stereochemical restraints or constraints. Here, the definition and calculation of the restraints that can be imposed on planar atomic groups, in particular the angle between such groups, are described. Detailed derivations of the restraint targets and their gradients are provided so that they can be readily implemented in other contexts. Practical implementations of the restraints, and of associated data structures, in theComputational Crystallography Toolbox(cctbx) are presented.

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