Effect of Opacity on the Solar Spectral Line of C I 165.7 nm by Escape Factor Treatment

In this article, we report that by using the intensity ratio of the (2-2) to (1-2) component of CI emission lines at about 165.7 nm, we determined the optical depth at the line center of the (2-2) component of CI emission lines by escape factor treatment. The optical depth at the line center of the (2-2) component is calculated to be 0.9998, which is a more reasonable value of solar spectral lines than the value that has been reported. The variation of the optical depth at the line center for different positions from the solar limb is discussed. Using the measured abundance of carbon and the results of ionization balance calculations, we estimate the electron density in the CI emitting region. The density of hydrogen is estimated in the CI emitting region by this method, and is testified to be a better value than the value that has been reported. This discussion will be significant in the analysis of opacity on the solar ultraviolet (UV) or extreme-ultraviolet (EUV) spectrum.     

The Opacity of the Solar Spectral Lines of CII 133.5 nm

Because the intensity ratio between two spectral lines arising from the same upper level can depend on opacity, we determine the optical depth of the solar atmosphere CII emission at about 133.5 nm. By introducing the measured abundance of carbon and the results of ionization balance calculations, we estimate the line-of-sight physical thickness of the regions emitting CII lines at about 133.5 nm. This discussion will be significant in the analysis of the solar spectrum.     

Electron density diagnostics by use of a collisional excitation model of the oxygen VI doublet in the solar transition region

ABSTRACT

For spectral diagnostics in the solar transition region under the collision–equilibrium condition, the method for electron density diagnostics by the collisional excitation is discussed in this paper. By using observed signal ratio of spectral lines produced by the oxygen VI ion, we discuss the electron density by this method. We find that this method is valid for a large region of signal ratio (from 2.001 to 4.162). We obtain that the electron density increases with increasing signal ratio of the oxygen VI doublet, and the plasma has an electron density on the order of magnitude of 10⁶–10⁷?cm^?3. This discussion will be significant for study on spectral diagnostics of the solar transition region.     

Coherence effects on photon absorption in optically thick plasmas

A kinetic photon transport model that accounts for spatial coherence is applied to line radiation in optically thick plasmas. It is shown that the photon emission and absorption processes are delocalized in space, which alters the global plasma opacity to spectral lines. Based on this analysis, we demonstrate that spectral profiles and escape factors can be much larger than expected from usual formulas.     

Exact results in modeling planetary atmospheres—II. Semi-gray atmospheres

We solve the radiative transfer equation for a semi-gray planetary atmosphere in radiative equilibrium, in an attempt to define an entirely analytical non-gray model atmosphere of finite optical thickness. The salient feature of the model is that the incident solar radiation is partitioned between two adjacent spectral domains—the “visible” and the “infrared”—in each of which the atmosphere's (effective) opacity is assumed to be independent of frequency (the semi-gray assumption). We envisage a plane-parallel atmosphere illuminated by a beam of parallel radiation and bounded below by a partially reflecting and emitting ground. The former emits infrared radiation, induced by the absorption of radiation both visible and infrared, deriving from the external irradiation as well as from the emission of the planet's surface layer. For an atmosphere with given single-scattering albedos and optical thicknesses in both the visible and infrared domains, we compute the temperature at every depth of the atmosphere, as well as the ground's temperature.     

Method to Calculate the Opacity of the Solar C III Spectral Lines

In this paper, using the intensity ratio between two spectral lines arising from the same lower level instead of the same upper level, we discuss the optical depth of the solar C III emission lines. The optical depth at the line center of the (2–2) component is calculated, which is in good agreement with the results derived by the previous method. The benefits of this method are discussed. Using the measured abundance of carbon in the solar spectrum and the results of ionization balance calculations, we estimate the line-of-sight physical thickness of the regions emitting C III lines, which is smaller than the previous result.     

Shapes of Fe <Emphasis Type="Italic">K</Emphasis><Subscript>α</Subscript> lines from annuli near black holes

Recent x-ray observations of microquasars and Seyfert galaxies reveal broad emission lines in their spectra, which can arise in the innermost parts of accretion disks. We consider a radiating annulus model to simulate spectral line shapes. That is a natural approximation for narrow emitting circular rings without extra astrophysical assumptions about emissivity laws. Recently, Müller and Camenzind (Astron. Astrophys. 413, 861 (2004)) presented results of their calculations and classified different types of spectral line shapes and described their origin. We clarified their hypothesis about an origin of double peaked and double horned line shapes. On the basis of results of numerical simulations, we showed that double peaked spectral lines arise almost for any locations of narrow emission rings (annuli), although Müller and Camenzind claimed that such profiles arise for relatively flat spacetimes and typical radii for emission region of about 25r _g. We showed that triangular spectral lines could arise for nearest annuli and high inclination angles. We discuss a possibility of appearance of narrow spectral line shapes as a result of spiraling evolution of matter along quasi-circular orbits which could be approximated by narrow annuli. The text was submitted by the author in English.     

“Energy levels and spectral lines of Ne?viii ” [Eur. Phys. J. D 39 , 173–188 (2006)]

Kramida and Buchet-Poulizac [Eur. Phys. J. D 39, 173 (2006)] provide a comprehensive compilation of Ne VIII energy levels and spectral lines. We are concerned about the data of one line treated in the second paragraph of Section 2, the line at 77.0 nm. This line is very important for solar physics investigations as it is a bright line emitted in the lower corona of the Sun, where mass flux and energy transport determine the properties of the nascent solar wind. Consequently, it has been studied in a number of investigations, of which we want to mention two. The results are published by Peter and Judge [Astrophys. J. 522, 1148 (1999)] and Dammasch et al. [Astron. Astrophys. 346, 285 (1999)]. Both these studies concluded that the rest wavelength of the Ne VIII line in question is 77.0428 nm with standard uncertainties of 0.7 pm and 0.3 pm, respectively. Dammasch et al. discussed, in particular, the uncertainty level of 0.5 pm stated by Bockasten et al. [Proc. Phys. Soc. 81, 522 (1963)]. The conclusion was that it is far too optimistic and not reliable. So, we take issue with the statement of the authors that the Bockasten et al. measurements of this line are the most accurate in the literature. If the Bockasten et al. value (77.0409 nm ± 0.0005 nm) [Proc. Phys. Soc. 81, 522 (1963)] for the rest wavelength of this line were true, it would imply downward movements in the solar corona that are in conflict with the measurements in other lines.     

Analysis of characteristic X-ray generation induced by laser plasma electrons accelerated by an electric field

The results of experiments devoted to the study of spectral, spatial, and time characteristics of a spectrally bright point x-ray source based on a vacuum diode with a laser-plasma cathode and a titanium needle anode with a photon energy approximately equal to 4.5 keV are presented. The experimental results revealed a considerable difference between the electron emission from laser plasma in a strong electric field and the explosive electron emission and demonstrated the effectiveness of laser plasma as an electron source. The optimization of the laser radiation power density, the accelerating voltage, and the interelectrode spacing made it possible to create a point x-ray source whose spectral brightness exceeds available sources in the class of small-size pulse x-ray instruments (tubes with explosive cathodes). It has been proved experimentally that the maximum contrast of the characteristic lines of the anode material is attained in the case of an optimal choice of accelerating voltage. The x-ray source has the following parameters: (1) spectral brightness of the K-lines of titanium of the order of 10²¹ photons/cm² s sr keV; (2) emitting region size of 250 mm; and (3) laser pulse duration less than 20 ns.     

卷云短波红外辐射特性

 采用离散纵标法耦合大气分子吸收,模拟计算了卷云大气的反射特性。研究了在短波波段卷云辐射性质随波长、卷云光学厚度、卷云有效尺度、云高和卷云中冰晶粒子形状等的变化关系,分析了卷云对大气红外背景辐射的影响。结果表明：在2.7 μm的水汽强吸收带上,卷云的出现明显增强了该波段的大气背景辐射,反射率随光学厚度和云高增大而增大。     

Analysis of an Inhomogeneous Semitransparent Plasma by the Lines in the Emission Spectrum

Using the methods of numerical simulation, we have investigated the dependence of the intensity and parameters of the spectral line profiles in the radiation of semitransparent plasma on its optical thickness, the degree of inhomogeneity, and the parameter distribution. As a model, we used the equilibrium plasma of argon with a given temperature profile on the observation line. The calculation has been performed for the spectral lines of the argon atom characterized by different broadening constants. On the basis of the results obtained it has been shown that it is possible to diagnose the plasma and determine the degree of its inhomogeneity and reabsorption by the parameters of the self-reversed profiles of the spectral lines. To diagnose the plasma in the absence of self-reversal, we propose to use the line intensities in the emission spectra of the plasma, including those obtained by probing it by its self-radiation. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 404–411, May–June, 2005.     

Optimization of soft x-ray line emission from laser-produced carbon plasma with laser intensity

Absolute measurement for He-α resonance (1s^{2 1}S₀?1s2p¹ P ₁, at 40.2 Å) line emission from a laser-produced carbon plasma has been studied as a function of laser intensity. The optimum laser intensity is found to be ≈1.3×10¹² W/cm² for the maximum emission of 3.2 × 10¹³ photons sr^?1 pulse^?1. Since this line lies in the water window spectral region, it has potential application in x-ray microscopic imaging of biological sample in wet condition. Theoretical calculation using corona model for the emission of this line is also carried out with appropriate ionization and radiative recombination rate coefficients     

基于高光谱技术建筑反射隔热涂料光谱特征减损规律的分析

受太阳辐射、气象等外界不可控因素的影响,建筑反射隔热涂料的反射隔热性能会逐渐减损。建筑反射隔热涂料性能在时间维度的变化是评价建筑在特定时段内节能效果的关键基础数据,明确建筑反射隔热涂料性能在时间维度的减损规律具有重要的现实与理论意义。建筑反射隔热涂料的反射、吸收特征是其性能的直观体现,借助高光谱技术定量分析涂料反射、吸收特征可正确揭示涂料性能在时间尺度的变化特征。为研究分析建筑反射隔热涂料性能在时间尺度上的减损规律,该研究利用高光谱技术,联合进行室内与外置实验采集涂料样本不同时期的光谱数据,并结合吸收峰深度、图谱分析法等光谱处理方法,定量分析涂料光谱反射特征、吸收特征在时间维度的变化特征,以研究分析涂料光谱反射率在外界环境影响下的减损规律。研究结论如下：(1)在350～2 250 nm波段区间内,建筑反射隔热涂料的光谱反射率随时间的增加而降低;光谱反射率的降低幅度在1月—5月内呈增加趋势,而在5月—10月内呈递减规律,且光谱反射率在可见光区间的降低幅度明显高于近红外区域。(2)建筑反射隔热涂料的吸收峰深度随时间的增加而降低,降低幅度在0～0.163范围内。(3)涂料厚度对涂料光谱反射率...     

Validation of HNO3 spectroscopic parameters using atmospheric absorption and emission measurements

The improved database of HNO₃ spectroscopic parameters in the 600–950 cm^?1 spectral region presented in [Gomez L, Tran H, Perrin A, Gamache RR, Laraia A, Orphal J, et al. Some improvements of the HNO₃ spectroscopic parameters in the spectral region from 600 to 950 cm^?1. JQSRT 2008, in press] is tested by comparisons between calculations and atmospheric remotely sensed absorption and emission spectra. The line parameters in the 11.3 μm region are validated using ground-based Fourier transform solar absorption measurements, whereas those in the 13.1 μm region are successfully tested using balloon-borne atmospheric emission spectra. In both regions, the quality of the line parameters and the consistency between band intensities is confirmed through comparisons with emission spectra collected by the satellite-borne MIPAS instrument.     

太阳过渡区紫外光谱的观测与诊断

太阳过渡区是太阳色球层顶到日冕底部的大气薄层。厚度仅几百千米,但其间太阳等离子体参数变化剧烈。过渡区的辐射多为光学薄的远紫外、极紫外发射谱线和背景连续谱线。由于地球大气的吸收,过渡区紫外光谱需通过天基观测才能实现。近几十年来,星载仪器的成功发射为太阳过渡区的研究打开了新纪元。工作回顾了太阳过渡区紫外光谱的观测历史和各类星载仪器,特别介绍了近十几年几种重要的光谱仪器。详细阐述了过渡区紫外光谱的发生率、电子密度和电子温度的诊断原理。讨论了过渡区紫外谱线的形状,并以SOHO/SUMER光谱仪为例介绍了表征谱线的几种重要参量及其物理意义。     

Influence of low-symmetry distortions on the luminescence of Cr4+-doped forsterite

By using pressure to vary the extent of nontetrahedral distortions of the Cr4+ site in Mg2SiO4, we reveal the important influence of the 3T1 state on the emission properties of the 3T2 state. We find that 3T1-3T2 mixing has a pronounced effect on the line shape and radiative decay rate of emission from the 3T2 state and that the extent of mixing depends critically on the magnitude of nontetrahedral distortions. The results provide an explanation for the wide variation of Cr4+ emission properties in different host lattices at ambient pressure and indicate that the tailoring of asymmetric distortions of luminescent centers represents an effective new strategy for tuning the linewidth of spectral transitions.     

Theoretical simulations of emission spectra of Fe^7＋ and Fe^＋8

The energy levels, oscillator strengths, spontaneous radiative decay rates, and electron impact collision strengths are calculated for Fe VIII and Fe IX using the recently developed flexible atomic code （FAC）. These atomic data are used to analyse the emission spectra of both laboratory and astrophysical plasmas. The nf-3d emission lines have been simulated for Fe VIII and Fe IX in a wavelength range of 6-14 nm. For Fe VIII, the predicted relative intensities of lines are insensitive to temperature. For Fe IX, however, the intensity ratios are very sensitive to temperature, implying that the information of temperature in the experiment can be inferred. Detailed line analyses have also been carried out in a wavelength range of 60-80 nm for Fe VIII, where the solar ultraviolet measurements of emitted radiation spectrometer records a large number of spectra. More lines can be identified with the aid of present atomic data. A complete dataset is available electronically from http：//www.astrnomy.csdb.cn/EIE/.     

样品厚度对薄膜法X射线荧光光谱测量的影响研究

分别以富集有Cr,Pb和Cd三种元素的尼龙薄膜样品及玻璃纤维滤膜为研究对象,采用滤膜叠加的方式,通过XRF光谱仪测量不同样品厚度下薄膜样品的XRF光谱,根据测得的尼龙薄膜样品中Cr,Pb,Cd元素及玻璃纤维滤膜中Ca,As和Sr元素特征XRF性质的变化,研究样品厚度对薄膜法XRF光谱测量的影响。结果表明：薄膜样品厚度对不同能量区间上元素特征谱线荧光性质的影响并不相同。元素特征谱线能量越大,元素特征X射线荧光穿透滤膜到达探测器的过程中损失越少;但由薄膜样品厚度增加引起的基体效应却越强,相应特征谱线位置处的背景荧光强度就越大,因此样品厚度增加所引起的基体效应对薄膜法XRF光谱测量的灵敏度影响就越大。对于特征谱线能量较低(能量小于7 keV)的元素,以增加薄膜样品厚度的方式来增加待测组分的质量厚度浓度,并不能有效地提高薄膜法XRF光谱测量的灵敏度;对于特征谱线能量较高的元素(能量＞7 keV),可以通过适当增加样品厚度以增加被测组分的质量厚度浓度的方式来提高XRF光谱测量的灵敏度,薄膜样品厚度在0.96～2.24 mm内,更有利于XRF光谱的测量与分析。该研究为大气及水体重金属薄膜法XRF光谱分析中薄样制备及富集技术提供了重要的理论依据。     

金等离子体M带谱强度的定量测量

在"神光II"多束高功率激光装置上利用列阵透镜匀滑钕玻璃波长0.53μm的强激光幅照平面金(Au)靶时产生X射线,本文给出了X射线绝对转换效率ξx。研究了多束倍频激光叠加驱动靶形成X射线背景光源辐射金M壳层1.8—3.1Kev带谱的特性,获得了不同激光功率密度及不同角度驱动靶面等几种条件下X射线能谱的定量测量结果和能谱分布。