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The main purpose of this paper is to obtain analytical solutions for radiative transfer equations related to the vertical structure of accretion discs with finite optical depth. In the non-gray atmosphere, we employ the optical-depth…

High Energy Astrophysical Phenomena · Physics 2020-06-24 Maryam Samadi , Fahimeh Habibi , Shahram Abbassi

We develop a new numerical scheme for solving the radiative transfer equation in a spherically symmetric system. This scheme does not rely on any kind of diffusion approximation and it is accurate for optically thin, thick, and intermediate…

Instrumentation and Methods for Astrophysics · Physics 2018-05-31 Torsten Stamer , Shu-ichiro Inutsuka

We develop an asymptotic preserving scheme for the gray radiative transfer equation. Two asymptotic regimes are considered: one is a diffusive regime described by a nonlinear diffusion equation for the material temperature; the other is a…

Numerical Analysis · Mathematics 2019-09-17 Min Tang , Li Wang , Xiaojiang Zhang

Numerical transfer matrices have been widely used in the study of wave propagation and scattering. These may be viewed as descretizations of a recently introduced fundamental notion of transfer matrix which admits a representation in terms…

Classical Physics · Physics 2023-10-03 Farhang Loran , Ali Mostafazadeh

We present a new formal solution of the Lagrangian equation of radiative transfer that is useful in solving the equation of radiative transfer in the presence of arbitrary velocity fields. Normally a term due to the inclusion of the…

Solar and Stellar Astrophysics · Physics 2009-11-13 S. Knop , P. H. Hauschildt , E. Baron

We present a novel generalization of the two-stream method of radiative transfer, which allows for the accurate treatment of radiative transfer in the presence of strong infrared scattering by aerosols. We prove that this generalization…

Earth and Planetary Astrophysics · Physics 2017-10-04 Kevin Heng , Daniel Kitzmann

A novel method for solving the linear radiative transport equation (RTE) in a three-dimensional homogeneous medium is proposed and illustrated with numerical examples. The method can be used with an arbitrary phase function A(s,s') with the…

Mathematical Physics · Physics 2007-05-23 George Panasyuk , John C. Schotland , Vadim A. Markel

Context: The solution of the nonlocal thermodynamical equilibrium (non-LTE) radiative transfer equation usually relies on stationary iterative methods, which may falsely converge in some cases. Furthermore, these methods are often unable to…

Solar and Stellar Astrophysics · Physics 2015-07-29 Julien Lambert , Eric Josselin , Nils Ryde , Alexandre Faure

An operator-splitting finite element scheme for the time-dependent, high-dimensional radiative transfer equation is presented in this paper. The streamline upwind Petrov-Galerkin finite element method and discontinuous Galerkin finite…

Numerical Analysis · Mathematics 2022-03-22 Sashikumaar Ganesan , Maneesh Kumar Singh

A discrete spherical harmonics method is developed for the radiative transfer problem in inhomogeneous polarized planar atmosphere illuminated at the top by a collimated sunlight while the bottom reflects the radiation. The method expands…

Instrumentation and Methods for Astrophysics · Physics 2018-02-07 Romuald Tapimo , Hervé Thierry Tagne Kamdem , David Yemele

We present a numerical implementation of radiative transfer based on an explicitly photon-conserving advection scheme, where radiative fluxes over the cell interfaces of a structured or unstructured mesh are calculated with a second-order…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Margarita Petkova , Volker Springel

The construction of exact solutions for radiative transfer in a plane-parallel medium has been addressed by Hemsch and Ferziger in 1972 for a partial frequency redistribution model of the formation of spectral lines consisting in a linear…

Solar and Stellar Astrophysics · Physics 2024-10-31 Hélène Frisch

We propose in this work a fast numerical algorithm for solving the equation of radiative transfer (ERT) in isotropic media. The algorithm has two steps. In the first step, we derive an integral equation for the angularly averaged ERT…

Numerical Analysis · Mathematics 2019-07-09 Kui Ren , Rongting Zhang , Yimin Zhong

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

We report a new analytical method for exact solution of homogeneous linear ordinary differential equations with arbitrary order and variable coefficients. The method is based on the definition of jump transfer matrices and their extension…

Mathematical Physics · Physics 2007-05-23 Sina Khorasani , Ali Adibi

Accurate photometric and kinematic modelling of disc galaxies requires the inclusion of radiative transfer models. Due to the complexity of the radiative transfer equation (RTE), sophisticated techniques are required. Various techniques…

Astrophysics · Physics 2009-11-06 Maarten Baes , Herwig Dejonghe

We solve the radiative transfer equation (RTE) in anisotropically scattering media as an infinite series. Each series term represents a distinct number of scattering events, with analytical solutions derived for zero and single scattering.…

High Energy Physics - Phenomenology · Physics 2024-07-25 Vladimir Allakhverdian , Dmitry V. Naumov

In this paper we study the application of a simplified method to solve the dynamic radiative transfer problem in expanding envelopes. The method, which requires a computational effort similar to that of the diffusion approximation, is based…

Astrophysics · Physics 2009-10-28 J. Gomez-Gomar , J. Isern

We study the direct and an inverse source problem for the radiative transfer equation arising in optical molecular imaging. We show that for generic absorption and scattering coefficients, the direct problem is well-posed and the inverse…

Analysis of PDEs · Mathematics 2008-03-31 Plamen Stefanov , Gunther Uhlmann

We consider an inverse source problem in the stationary radiative transport through an absorbing and scattering medium in two dimensions. Using the angularly resolved radiation measured on an arc of the boundary, we propose a numerical…

Numerical Analysis · Mathematics 2023-06-08 Hiroshi Fujiwara , Kamran Sadiq , Alexandru Tamasan