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A general theoretical framework is developed for interpreting spectropolarimetric observations of optically thin emission line scattering from small dust particles. Spatially integrated and spatially resolved line profiles of both scattered…

Astrophysics · Physics 2009-10-22 W. J. Henney

In the present paper we consider the problem of resonance line polarization formed in the spherically symmetric expanding atmospheres. For the solution of the concerned polarized transfer equation we use the comoving frame formulation, and…

Solar and Stellar Astrophysics · Physics 2020-01-20 A. Megha , M. Sampoorna , K. N. Nagendra , L. S. Anusha , K. Sankarasubramanian

The atmospheres of planets (including Earth) and the outer layers of stars have often been treated in radiative transfer as plane-parallel media, instead of spherical shells, which can lead to inaccuracy, e.g. limb darkening. We give an…

Statistical Mechanics · Physics 2009-11-11 Michael J. Caola

Analytic solutions to the nonlinear radiation diffusion equation with an instantaneous point source for a non-homogeneous medium with a power law spatial density profile, are presented. The solutions are a generalization of the well known…

Fluid Dynamics · Physics 2021-06-02 Menahem Krief

This work considers the propagation of high-frequency waves in highly-scattering media where physical absorption of a nonlinear nature occurs. Using the classical tools of the Wigner transform and multiscale analysis, we derive semilinear…

Analysis of PDEs · Mathematics 2025-04-23 Joseph Kraisler , Wei Li , Kui Ren , John C. Schotland , Yimin Zhong

In the previous paper we considered two classic problems - the diffuse reflection of the light beam from semi-infinite atmosphere, and the Milne problem. For both problems we used the technique of invariance principle. In this paper we…

Solar and Stellar Astrophysics · Physics 2015-06-22 N. A. Silant'ev , G. A. Alekseeva , V. V. Novikov

We develop a method of analyzing radio frequency spectral line observations to derive data on the temperature, density, velocity, and molecular abundance of the emitting gas. The method incorporates a radiative transfer code with a new…

Astrophysics · Physics 2009-11-10 Eric Keto , George B. Rybicki , Edwin A. Bergin , Rene Plume

Many stars, active galactic nuclei, accretion discs etc. are affected by the stochastic variations of temperature, turbulent gas motions, magnetic fields, number densities of atoms and dust grains. These stochastic variations influence on…

Solar and Stellar Astrophysics · Physics 2017-12-20 N. A. Silant'ev , G. A. Alekseeva , V. V. Novikov

Two methods are developed for solving the steady-state spherically symmetric radiative transfer equation for resonance line radiation emitted by a point source in the Intergalactic Medium. One method is based on solving the ray and moment…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jonathan Higgins , Avery Meiksin

The nonlinear propagation of the dust-acoustic bright and dark envelope solitons in an opposite polarity dusty plasma system (composed of non-extensive $q$-distributed electrons, isothermal ions, and positively as well as negatively charged…

Plasma Physics · Physics 2019-03-27 S. Jahan , N. A. Chowdhury , A. Mannan , A. A. Mamun

Non-stationary saturation of inhomogeneously broadened EPR lines is studied when cross-relaxation has the characteristics of spectral diffusion. A system of generalized kinetic equations is solved in quadratures in this approximation. The…

Statistical Mechanics · Physics 2020-01-20 Zura Kakushadze

This paper concerns the derivation of radiative transfer equations for acoustic waves propagating in a randomly fluctuating half-space in the weak-scattering regime, and the study of boundary effects through an asymptotic analysis of the…

Classical Physics · Physics 2022-12-01 Adel Messaoudi , Regis Cottereau , Christophe Gomez

Freely oriented small anisotropic grains and molecules depolarize radiation both in single scattering and in the process of multiple scattering. Especially large depolarization occurs for resonant scattering corresponding to the electron…

Solar and Stellar Astrophysics · Physics 2015-06-17 N. A. Silant'ev , G. A. Alekseeva , V. V. Novikov

Optical/UV photons and even harder radiation components in galaxies are absorbed and scattered by dust and re-emitted at infrared wavelengths. For a better understanding of the obscured regions of the galaxies detailed models of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Ralf Siebenmorgen , Frank Heymann

The problem of radio wave reflection from an optically thick plane monotonous layer of magnetized plasma is considered at present work. The plasma electron density irregularities are described by spatial spectrum of an arbitrary form. The…

Plasma Physics · Physics 2009-09-25 N. A. Zabotin , A. G. Bronin

Radiation of a charged particle moving parallel to a inhomogeneous surface is considered. Within a single formalism periodic and random gratings are examined. For the periodically inhomogeneous surface we derive new expressions for the…

Accelerator Physics · Physics 2010-10-12 Zh. S. Gevorkian

We come back to the analytical solution of the standard transfer problem in a stellar atmosphere. It consists in solving the radiative transfer equation in a homogeneous and isothermal plane-parallel atmosphere, with light scattering taken…

Astrophysics · Physics 2007-05-23 L. Chevallier , B. Rutily

We consider the radiation transfer problem in the discrete-ordinate, plane-parallel approach. We introduce two benchmark problems with exact known solutions and show that for strongly non-homogeneous media the homogeneous layers…

Computational Physics · Physics 2007-05-23 M. -P. Zorzano , A. M. Mancho , L. Vazquez

The linear polarization signals produced by scattering processes in strong resonance lines are rich in information on the magnetic and thermal structure of the chromosphere and transition region of the Sun and of other stars. A correct…

Solar and Stellar Astrophysics · Physics 2015-06-19 Luca Belluzzi , Javier Trujillo Bueno

We present a numerical code for continuum radiative transfer that is based on the idea of a `library' describing the relation between the intensity of the local radiation field and the resulting dust emission. With this information and…

Astrophysics · Physics 2009-11-07 M. Juvela , P. Padoan
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