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This proposal relates to the design, analysis and application of a novel numerical scheme for the solution of axisymmetric scattering problems. To this end, a procedure is introduced to iteratively evaluate the solution of the…

Numerical Analysis · Mathematics 2025-10-20 YoungAe Han

We address the classical stellar-atmosphere problem and describe our method of numerical solution in detail. The problem consists of the solution of the radiation transfer equation under the constraints of hydrostatic, radiative and…

Astrophysics · Physics 2007-05-23 K. Werner , J. L. Deetjen , S. Dreizler , T. Nagel , T. Rauch , S. L. Schuh

In this paper we present a multilevel projection-based iterative scheme for solving thermal radiative transfer problems that performs iteration cycles on the high-order Boltzmann transport equation (BTE) and low-order moment equations.…

Numerical Analysis · Mathematics 2026-03-18 Joseph M. Coale , Dmitriy Y. Anistratov

When solving the time-dependent radiative transport equation (RTE), implicit time discretization is often employed for its robustness and stability. This results in a sequence of steady-state RTEs with identical cross-sections but varying…

Numerical Analysis · Mathematics 2026-04-24 Qinchen Song , Lei Zhang , Min Tang

A new, very fast method for 3D radiative transfer on fully threaded grids with arbitrarily high angular resolution is presented. The method uses completely cell-based discretization, and is ideally suited for problems with diffuse…

Astrophysics · Physics 2009-11-11 A. O. Razoumov , C. Y. Cardall

We formulate the problem of a two-level system in a linearly polarized laser field in terms of a nonlinear Riccati-type differential equation and solve the equation analytically in time intervals much shorter than half the optical period.…

Quantum Physics · Physics 2007-05-23 R. Parzynski , M. Sobczak , A. Plucinska

We propose a numerical interferometry method for identification of optical multiply-scattering systems when only intensity can be measured. Our method simplifies the calibration of optical transmission matrices from a quadratic to a linear…

Signal Processing · Electrical Eng. & Systems 2020-02-17 Sidharth Gupta , Rémi Gribonval , Laurent Daudet , Ivan Dokmanić

The paper describes two iterative algorithms for solving general systems of M simultaneous linear algebraic equations (SLAE) with real matrices of coefficients. The system can be determined, underdetermined, and overdetermined. Linearly…

Numerical Analysis · Mathematics 2025-10-20 A. S. Kondratiev , N. P. Polishchuk

We have introduced the generalized alternating direction implicit iteration (GADI) method for solving large sparse complex symmetric linear systems and proved its convergence properties. Additionally, some numerical results have…

Numerical Analysis · Mathematics 2024-04-19 Juan Zhang , Wenlu Xun

The calculation of the emerging radiation from a model atmosphere requires knowledge of the emissivity and absorption coefficients, which are proportional to the atomic level population densities of the levels involved in each transition.…

Instrumentation and Methods for Astrophysics · Physics 2024-09-25 D. Arramy , J. de la Cruz Rodríguez , J. Leenaarts

In this paper we want to propose practical numerical methods to solve a class of initial-boundary problem of time-space fractional convection-diffusion equations (TSFCDEs). To start with, an implicit difference method based on two-sided…

Numerical Analysis · Mathematics 2021-07-26 Xian-Ming Gu , Ting-Zhu Huang , Cui-Cui Ji , Bruno Carpentieri , Anatoly A. Alikhanov

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

Simultaneous imaging of fluorescence-labeled and label-free phase objects in the same sample provides distinct and complementary information. Most multimodal fluorescence-phase imaging operates in transmission mode, capturing fluorescence…

Optics · Physics 2024-08-20 Renzhi He , Yucheng Li , Junjie Chen , Yi Xue

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

Photoacoustic tomography (PAT) is a promising imaging technique that can visualize the distribution of chromophores within biological tissue. However, the accuracy of PAT imaging is compromised by light fluence (LF), which hinders the…

Image and Video Processing · Electrical Eng. & Systems 2023-12-11 Zhaoyong Liang , Shuangyang Zhang , Zhichao Liang , Zhongxin Mo , Xiaoming Zhang , Yutian Zhong , Wufan Chen , Li Qi

We present a general formalism for computing self-consistent, numerical solutions to the time-dependent radiative transfer equation in low velocity, multi-level ions undergoing radiative interactions. Recent studies of time-dependent…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Matthew van Adelsberg , Rosalba Perna

This paper considers the non-Hermitian Zakharov-Shabat (ZS) scattering problem which forms the basis for defining the SU$(2)$-nonlinear Fourier transform (NFT). The theoretical underpinnings of this generalization of the conventional…

Numerical Analysis · Mathematics 2018-07-24 Vishal Vaibhav

The nonlinear Fourier transform (NFT), a powerful tool in soliton theory and exactly solvable models, is a method for solving integrable partial differential equations governing wave propagation in certain nonlinear media. The NFT…

Information Theory · Computer Science 2014-10-09 Mansoor I. Yousefi , Frank R. Kschischang

We describe a highly flexible framework to solve 3D radiation transfer problems in scattering dominated environments based on a long characteristics piece-wise parabolic formal solution and an operator splitting method. We find that the…

Astrophysics · Physics 2009-11-11 Peter H. Hauschildt , E. Baron

This paper presents an innovative set of tools to support a methodology for the multichannel interpolation (MCI) of a discrete signal. It is shown that a bandlimited signal $f$ can be exactly reconstructed from finite samples of $g_k$…

Information Theory · Computer Science 2019-04-12 Dong Cheng , Kit Ian Kou