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We consider the classical time-dependent problem of diffuse reflection of the line-radiation from a semi-infinite absorbing and scattering atmosphere. By the example of the simplest 1D problem it is shown how its solution is constructed in the general case, when both the photon lifetime in the absorbed state and the time of its travel between two consecutive acts of scattering are taken into account. The numerical values of the coefficients in the expansion of the reflection function in the Neumann series are given. The obtained solution is applied to the problem, in which the scattering in both the spectral line and in the continuous spectrum is taken into account.

X-ray emissions (bremsstrahlung radiation, line radiation, and radiative recombination) from spherical plasma focus (SPF) device are investigated with the developed spherical MHD model for nitrogen (N) and neon (Ne) gases with respect to gas pressure, which is varied from 0.1 Torr to 7 Torr. Ion density, plasma velocity, pinch temperature, and peak current are also calculated for N and Ne gases. The total capacitance, external inductance, charging voltage, and stored energy as the operational conditions of the SPF device in this study are 432 µF, 36 nH, 25 kV, and 135 kJ. The maximum current is achieved at 7 Torr for both N (1561 kA) and Ne (1525 kA). It is found that there is an optimum pressure point for both x-rays (bremsstrahlung radiation, line radiation, and radiative recombination) and the used gases (N and Ne), separately. While the optimum pressure of bremsstrahlung radiation for N and Ne gases are 0.9 Torr and 1 Torr, respectively, these optimum pressures of radiative recombination and line radiation are 1 Torr for N gas and 1.1 Torr for Ne gas, respectively. It is also found that line radiation constitutes the big portion of the soft x-ray (SXR) emissions from SPF device. Line radiations of N at 1 Torr and Ne at 1.1 Torr are 911 J (91% of total N SXRs) and 3036.5 J (93.1% of total Ne SXRs), respectively, which shows that SPF device can be considered as a good SXR source. Ion densities and peak currents at 7 Torr are calculated as 21.88 × 1023 m−3 with 1561 kA peak current for N gas and 15.98 × 1023 m−3 with 1525 kA peak current for Ne gas.

A transport equation for dipole radiation is derived from quantum electrodynamics. The radiation field is described in terms of a space–time Wigner function, which accounts for the position–momentu...

The original purpose of the study is to solve the inverse problem of synthesis of freeform optical elements. This article describes a numerical approach for synthesis of freeform refracting surfaces forming a line radiation pattern.

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In this paper we report the experimental implementation of a theoretically-proposed technique for creating a photoionized plasma in the laboratory using X-ray line radiation. Using a Sn laser-plasma to irradiate an Ar gas target, the photoionization parameter, \xi = 4{\pi}F/Ne, reached values of order 50 erg cm/s, where F is the radiation flux in erg/cm2/s. The significance of this is that this technique allows us to mimic effective spectral radiation temperatures in excess of 1 keV. We show that our plasma starts to be collisionally dominated before the peak of the X-ray drive. However, the technique is extendable to higher energy laser systems to create plasmas with parameters relevant to benchmarking codes used to model astrophysical objects., Comment: 10 pages; 8 figures; Physical Review E, in press

The article describes a method of measuring engine oil wear metals by Atomic Absorption Spectrometry (AAS), which is an analytical method used to determine the concentrations of various elements in the sample. Atoms of different elements absorb different wavelengths of light in proportion to the quantities in which they are represented, as an analytical measurement property is performing absorption of radiation by free atoms of the reference element. AAS method with flame atomization allows measuring the concentration of about 60 elements of the periodic table in a solution with a sensitivity from hundredths to hundred μg.ml-1. It is used in the analysis of samples of different origins. This method makes up a significant part of monitoring low levels of toxic elements in environmental samples, which is very good to be used for its high sensitivity and selectivity. The aim of the study was the evaluation of the composition of wear particles tested oil samples by AAS, which is highly accurate and a fully automated tribotechnical diagnostics method. The intensity of each line radiation gives information about the content of investigated metals in the tested samples of motor oils, which enable us to identify not only the place from which abrasion arises, but also reveals the cause of the critical condition of the mechanism.

This paper studies the characteristic frequency of partial discharge in transformer oil [, and with the spectrum characteristics of partial discharge in air was measured by the comparison of uhf signal inside the metal tank and the attenuation characteristics and metal wire in the air on the radiation characteristics of uhf signals. The results show that the frequency spectrum of the partial discharge in transformer oil is higher than the frequency spectrum of the partial discharge in air. Ultra high frequency signal have the oscillation characteristics in the metal box body propagation. The transformer has the certain ability of outgoing line radiation of partial discharge signal inside.

Origin of enigmatic line profiles of extremely luminous type IIn supernova SN~2006gy on day 96 is explored. Among conceivable possibilities the most preferred is the model that suggests holes in the optically thick cool dense shell (CDS). The line radiation emitted at the inner side of the opaque CDS escapes through the holes thus producing unusual line profile with the emission shifted redward. The holes could emerge as a result of a vigorous Rayleigh-Taylor instability leading to the CDS fragmentation. The model light curve with the CDS fragmentation is shown to be consistent with the SN~2006gy bolometric light curve., MNRAS, accepted

We investigate the possibility that the decrease in the relative luminosity of the 158 micron [CII] line with the far-infrared luminosity in extragalactic sources stems from a stronger contribution from the heated dust emission in the more distant sources. Due to the flux limited nature of these surveys, the luminosity of the detected objects increases with distance. However, the [CII] luminosity does not climb as steeply as that of the far-infrared, giving the decline in the L_[CII]/L_FIR ratio with L_FIR. Investigating this further, we find that the [CII] luminosity exhibits similar drops as measured against the carbon monoxide and radio continuum luminosities. The former may indicate that at higher luminosities a larger fraction of the carbon is locked up in the form of molecules and/or that the CO line radiation also contributes to the cooling, done mainly by the [CII] line at low luminosities. The latter hints at increased activity in these galaxies at greater distances, so we suggest that, in addition to an underlying heating of the dust by a stellar population, there is also heating of the embedded dusty torus by the ultra-violet emission from the active nucleus, resulting in an excess in the far-infrared emission from the more luminous objects., Comment: 9 pages, accepted by A&A

Most of the mass of the interstellar medium is in neutral phases that are heated by far-ultraviolet radiation from star forming regions. The gas, in turn, emits line radiation in the infrared and submillimeter that potentially has great diagnostic value. In this paper, we will review the physical processes (including heating, cooling, gas phase and grain surface chemistry) that give rise to this line emission and present diagnostic diagrams. We will also discuss several examples where models of neutral gas emission have been used to interpret line emission, including observations of H 2 O and O 2 in molecular clouds and an example which points out the caution that must be used when applying the diagnostics to kiloparsec-sized regions in other galaxies.

The Pulkovo Spectrophotometric Data Base is used to determine the expansion velocities and radii of the continuum emission layers of the stars RR SCO and OMICR CET. Dependences of the radii and velocities on the phase of the variability cycle are found which agree with the known values obtained from the layers which emit line radiation.

K-series line radiation emission of Mo and Cu from a low energy Mather-type plasma focus is investigated. Quantrad Si pin diodes are employed as time resolved X-ray detectors, where as a pin hole camera is used for time integrated analysis. The measurable X-ray flux for hydrogen is observed in the pressure range of 0.5–3.5 mbar. Mo and Cu K-line radiation emission in this geometry has the highest values of about 0.05 J/sr and 0.17 J/sr, respectively at a filling pressure of 2.0 mbar. The corresponding efficiencies are 0.03% and 0.09%, respectively. Total X-ray emission and efficiency in 4 π -geometry are also obtained with values 4.12 J and 0.18% at 2.0 mbar. The Mo K-line radiation emission may result due to interaction of energetic electron beam emitted from the focus region with the molybdenum insert.  2002 Elsevier Science B.V. All rights reserved.

We present high-precision optical spectropolarimetry of the Seyfert 1 galaxy Fairall 51 (F51) taken with FORS1 at the VLT. The observed spectrum shows unpolarized and linearly polarized components. The AGN continuum and the broad lines show (after correction for the Galactic interstellar polarization and the light contribution of the F51 host galaxy) a practically identical amount of intrinsic polarization ranging from 5% in the red to 13% in the UV. The narrow lines are unpolarized or show only little intrinsic polarization. The observed AGN continuum and the broad line radiation can be explained by a combination of reddened (and attenuated) direct light and scattered light reflected from an optically thin dust region. Hence, within the framework of the unication scheme of AGN, the Seyfert 1 galaxy F51 appears to be an example of a borderline Seyfert 1/Seyfert 2 case where the nucleus is partially obscured like for other type 1 AGN with high intrinsic scattering polarization. It is found that the scattering region in F51 is located far from the BLR and the continuum source. Thanks to this special scattering conguration, we were able to study the kinematics (line proles) of the broad line region from two dierent viewing angles, one along the line of sight (in total light) and one via the scattering region (in polarized light). The line proles in polarized and total light are found to be indistinguishable to a very high accuracy, strongly indicating that the velocity eld of the F51 BLR is essentially spherically symmetric.

X-radiation emission from a low-energy Mather-type plasma focus operated with argon is investigated. Attention is paid to finding the pressure range for the highest argon K-series line emission. The argon line radiation yield is highest at 1.5 mbar and the emitted energy in 4π geometry is estimated to be about 30 mJ, with a system efficiency of 0.0015%. The emission at an energy exceeding 3 keV is found to be highest at a 0.5 mbar filling pressure, giving a total yield of 0.7 J in 4π geometry, which corresponds to a device efficiency of about 0.028%. This emission is mainly due to the interaction of energetic electrons with the anode.

This paper reports preliminary results of experimental measurements of the emission and absorption of laser-induced spark in air, O2, N2, H2, and CH4 using a Q-switched Nd-Yag laser operating at 532 nm and 1064 nm, with a pulse duration of 5.5 ns. Line radiation spectra observed for spark in air consist of N and O lines that are distinctly observed in the region from 399.49 to 870.2 nm. The spectra of spark created in CH4 show strong H lines centered at 656.46 nm. Some rather weak emission lines are also observed at 460.4, 497.0, 497.3, and 503.7 nm. Laser wavelength has a strong effect on the absorption data obtained as a function of total laser energy Eo. However, in case of variable pressure, its effect is considered to be within experimental fluctuations.

Plasma parameters in the new divertor configuration of the high field FTU tokamak have been analyzed by means of the numerical codes FTUDIV and EPIT. The question of achieving high recycling and detached regimes for the FTU divertor operation is addressed in the paper.

Magnetospheric line radiation (MLR) events are relatively narrowband VLF signals that sometimes drift in frequency and have been observed in both ground-based and satellite data sets. We present the results of a survey undertaken on the basis of measurements made of MLR events observed at Halley, Antarctica (75°30′S, 26°54′W, L ≈ 4.3), in June, July, September, and December 1995, specifically looking at the temporal properties of Halley MLR events. We find that (1) single MLR lines described in previous papers tend to be comprised of up to 3 lines with widths of 5–10 Hz. (2) The multiple lines show highly variable spacings (e.g., < 10 to ∼100 Hz). (3) The rate at which MLR lines appears from the noise is ∼0.1 to 0.2 dB s−1, considerably smaller than previously reported for other VLF emissions. MLR exhibits slow growth, relative frequency stability, and long lifetimes in comparison with other coherent whistler mode emissions and thus may be generated by a separate mechanism. (4) The diurnal occurrence of MLR observed at Halley is twin-peaked, indicating an association with a combination of chorus and midlatitude hiss. (5) MLR occurrence rates can vary greatly within a given month, but the proportion of MLR present as part of the overall Halley wave activity is roughly constant (10–13%) throughout the year. (6) The occurrence of MLR activity at Halley is weakly linked to geomagnetic activity but only 24–48 hours after very large storms (Kp > 6), which affects only 8% of the total MLR events in this study. For smaller storms, there is little effect, although MLR events tend not to occur when the geomagnetic activity has been quiet in the previous 48 hours. (7) There is no dependence of MLR occurrence rates upon the instantaneous levels of geomagnetic activity. (8) The average duration of a typical MLR event at Halley is ∼ 30 min, quite similar to previous reports.

NGC 1275, the central galaxy of the Perseus cluster, contains a remarkable cool ISM. This gas is arrayed in a series of filaments extending over 30 kpc with an extension of 70 kpc to the north. These emit substantial cooling line radiation from HII, a hot H2 zone, and CO in a cool molecular region which contains most of the gas mass. This contribution briefly discusses some of the issues raised by the existence of this remarkable ISM system, including its connections to galactic feedback processes (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Experimental and theoretical cross sections for the excitation of ground-state lithium by ${\mathrm{H}}^{+}$ and ${\mathrm{He}}^{2+}$ impact are presented for the 2--30 keV/amu energy regime. $\mathrm{Li}(2s)$ excitation up to the $\mathrm{Li}(n=4)$ level was simulated by means of the atomic-orbital close-coupling method. Experimentally, absolute emission cross sections were determined by observing the $\mathrm{LiI}(nd\ensuremath{-}2p,n=3--6)$ and $\mathrm{LiI}(ns\ensuremath{-}2p,n=4--6)$ line radiation after ion impact. Furthermore, a few measurements have been performed on high-$n$ excitation $[\mathrm{Li}(2\stackrel{\ensuremath{\rightarrow}}{s}nd,n=7--9)]$ by ${\mathrm{He}}^{2+}$ impact.

Transverse losses from hot dense plasma were studied on the GOL-3 facility. Concentration of impurities, effective charge of ions in plasma, line radiation power and charge exchange loses were found from spectroscopic measurements in VUV and visible spectral regions. Estimation of effective charge of ion required for comparison of measurements and predictions of global confinement time was derived from the measurements of impurities concentration.

This paper describes the preliminary results of a study of the paint layers in 17th-century paintings belonging to the collection of the Wilanow Palace Museum. The works chosen for examination are of great importance to the Museum, as they might have been painted by court artists of King John III Sobieski. The aim of the study was therefore to determine the technological structure of the paintings, to determine the scope of conservation interventions and, above all, to gather comparative material that would serve to conduct further multidisciplinary attributive research. The presentation relates to studies in which laser-induced breakdown spectroscopy (LIBS) and optical microscopy were used as diagnostic tools. LIBS is based on the evaporation of a small amount of the material under investigation, and the generation of plasma which emits continuum and line radiation. The analysis of line radiation allows us to identify the elements appearing in the sample being investigated. The microscope pictures were taken using a Bresser Digital Hand Micro 1.3Mpx and the Hirox 8700 microscopes. The results obtained have confirmed the utility of the LIBS method in the study of artworks. They have also proven that it can be used as a method to complement microchemical analysis, as well as an method to identify and examine artworks from which samples cannot be taken, as it is micro-destructive and the analysis can be conducted directly on the object, without the need to take samples.

The toroidal dispersal of laser blow-off injected aluminum is studied. The spatial distribution of Al I, Al II, and Al III line radiation is measured as a function of time. The measured toroidal distribution of the aluminum ions is compared with the distribution calculated by a one-dimensional transport simulation based on the kinetic theory, and a satisfactory agreement is found showing that the toroidal spread is determined only by Coulomb collisions.

Three-dimensional calculations of the electron source in plasmas of the TJ-II stellarator (Madrid, Spain) are performed using the Monte Carlo code EIRENE. When possible, the results are compared with diagnostic measurements in equivalent coordinates. Examples are shown for the Hα light evolution during a plasma collapse, CX fluxes, neutrals distributions along diagnostic chords and line radiation emissivities.

A technique to derive the coronal density irregularity factor\(\overline {n^2 } /(\bar n)^2 \), wheren is the electron density, has been proposed by Fineschi and Romoli (1993). This technique will exploit the unique UVCS capability of cotemporal and cospatial measurements of both UV line radiation and K-coronal polarized brightness,pB.