Reviews of topical problems

Stationary radiation of objects with scattering media

Institute for High Energy Densities, Associated Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya 13/19, Moscow, 127412, Russian Federation

The radiation observed inside or outside a stationary radiator with a scattering medium is a sum of components, each being determined by, first, the primary radiation from some part of the radiator and, second, the probability of this radiation reaching the region where it is observed. In this review, general and rather simple relations between these components are discussed. These relations, unlike the components themselves, are independent of the specific optical characteristics of the object as well as of its geometry, inhomogeneity, etc. In deriving the relations, the situations in which geometrical optics is either applicable or inapplicable to radiation in a scattering medium are considered. For the case where geometrical optics does apply, stationary relations are derived from the probabilistic stationarity condition for radiation passing through the medium, i.e., from the fact that all radiation emitted in a stationary regime disappears with probability unity. Equilibrium relations are derived from the stationary relations in the particular case of a thermal radiator in an isothermal cavity. To derive the stationary relations in the geometrical optics approximation, we obtain general solutions of the linear equation of transfer using the Green function approach. If geometrical optics cannot be applied to a scattering and radiating medium, only relations for the components of outgoing thermal radiation are obtained, and the generalized Kirchhoff law, obtained by Levin and Rytov using statistical radio-physics methods, is employed. In this case, stationary relations are also derived from a probabilistic stationarity condition; the equilibrium relations follow from the stationary ones as well as from the equilibrium condition for radiation in the isothermal cavity. The quantities involved in all the relations obtained are a subject of experimental and computational spectroscopic studies. Examples of current and potential applications are given. The relations have been successfully used in diverse spectroscopic experiments — in studies of the effects of macroscopic particles on the emission line profiles in dusty plasmas and in temperature measurements in strongly scattering solid porous materials.

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Fulltext is also available at DOI: 10.1070/PU2001v044n12ABEH000997
PACS: 44.30.+v, 44.40.+a, 95.30.Jx (all)
DOI: 10.1070/PU2001v044n12ABEH000997
Citation: Vasil’eva I A "Stationary radiation of objects with scattering media" Phys. Usp. 44 1255–1282 (2001)
BibTexBibNote ® (generic)BibNote ® (RIS) MedlineRefWorks
PT Journal Article
TI Stationary radiation of objects with scattering media
AU Vasil’eva I A
FAU Vasil’eva IA
DP 10 Dec, 2001
TA Phys. Usp.
VI 44
IP 12
PG 1255-1282
RX 10.1070/PU2001v044n12ABEH000997
SO Phys. Usp. 2001 Dec 10;44(12):1255-1282

Оригинал: Васильева И А «Стационарное излучение объектов с рассеивающими средами» УФН 171 1317–1346 (2001); DOI: 10.3367/UFNr.0171.200112c.1317

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