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A method for the fast and accurate solution of the radiative transfer equation in plane-parallel media with coherent isotropic scattering is presented. This largely analytical approach uses the formalism of meromorphic functions in order to…

Astrophysics · Physics 2007-05-23 G. V. Efimov , N. V. Kryzhevoi , W. von Waldenfels , R. Wehrse

Consider the elastic scattering of a time-harmonic wave by multiple well separated rigid particles in two dimensions. To avoid using the complex Green's tensor of the elastic wave equation, we utilize the Helmholtz decomposition to convert…

Numerical Analysis · Mathematics 2020-08-17 Jun Lai , Peijun Li

The achievable data rates of current fiber-optic wavelength-division-multiplexing (WDM) systems are limited by nonlinear interactions between different subchannels. Recently, it was thus proposed to replace the conventional Fourier…

Information Theory · Computer Science 2015-01-27 Sander Wahls , H. Vincent Poor

A symplectic pseudospectral time-domain (SPSTD) scheme is developed to solve Schrodinger equation. Instead of spatial finite differences in conventional finite-difference time-domain (FDTD) method, the fast Fourier transform is used to…

Computational Physics · Physics 2018-05-09 Jing Shen , Wei E. I. Sha , Xiaojing Kuang , Jinhua Hu , Zhixiang Huang , Xianliang Wu

Starting from a comparison of some established numerical algorithms for the computation of the eigenvalues (discrete or solitonic spectrum) of the non-Hermitian version of the Zakharov-Shabat spectral problem, this article delivers new…

Numerical Analysis · Mathematics 2018-09-11 A. Vasylchenkova , J. E. Prilepsky , D. Shepelsky , A. Chattopadhyay

For the accurate representation and reconstruction of band-limited signals on the sphere, an optimal-dimensionality sampling scheme has been recently proposed which requires the optimal number of samples equal to the number of degrees of…

Information Theory · Computer Science 2017-09-11 Wajeeha Nafees , Zubair Khalid , Rodney A. Kennedy , Jason D. McEwen

Aims. The main goal of this paper is to present an accurate and efficient numerical strategy for solving the radiative transfer problem for polarised radiation in strong resonance lines forming out of local thermodynamic equilibrium, taking…

Observations and theoretical calculations have shown the importance of non-spherically symmetric structures in supernovae. Thus, the interpretation of observed supernova spectra requires the ability to solve the transfer equation in 3-D…

Solar and Stellar Astrophysics · Physics 2015-05-13 E. Baron , Peter H. Hauschildt , Bin Chen

Computing the Sparse Fast Fourier Transform(sFFT) of a K-sparse signal of size N has emerged as a critical topic for a long time. The sFFT algorithms decrease the runtime and sampling complexity by taking advantage of the signal inherent…

Signal Processing · Electrical Eng. & Systems 2020-12-16 Bin Li , Zhikang Jiang , Jie Chen

Assume a time-harmonic elastic wave is incident onto a penetrable anisotropic body embedded into a homogeneous isotropic background medium. We propose an equivalent variational formulation in a truncated bounded domain and show the…

Analysis of PDEs · Mathematics 2016-12-21 Gang Bao , Guanghui Hu , Jiguang Sun , Tao Yin

One of the most efficient ways to produce unconditional simulations is with the kernel convolution using fast Fourier transform (FFT) [1]. However, when data is located on a surface, this approach is not efficient because data needs to be…

Computation · Statistics 2016-01-18 Alexander Gribov

The Helmholtz equation arises in the study of electromagnetic radiation, optics, acoustics, etc. In spherical coordinates, its general solution can be written as a spherical harmonic series which satisfies the radiation condition at…

Numerical Analysis · Computer Science 2012-04-13 Youngae Han

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

We present a spectrally accurate method for the rapid evaluation of free-space Stokes potentials, i.e. sums involving a large number of free space Green's functions. We consider sums involving stokeslets, stresslets and rotlets that appear…

Numerical Analysis · Mathematics 2018-01-18 Ludvig af Klinteberg , Davoud Saffar Shamshirgar , Anna-Karin Tornberg

The stochastic differential and integral equations describing the system of particles weakly interacting among themselves which are absorbed and scattered by particles of a medium are considered. The time-dependent transport equation with…

Mathematical Physics · Physics 2010-03-15 Igor Kharin

A common problem in cosmology is to integrate the product of two or more spherical Bessel functions (sBFs) with different configuration-space arguments against the power spectrum or its square, weighted by powers of wavenumber. Naively…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-03 Zachary Slepian , Yin Li , Marcel Schmittfull , Zvonimir Vlah

This paper introduces a fast algorithm, applicable throughout the electromagnetic spectrum, for the numerical solution of problems of scattering by periodic surfaces in two-dimensional space. The proposed algorithm remains highly accurate…

Computational Physics · Physics 2018-05-25 Oscar Bruno , Martín Maas

An iterative algorithm is adopted to construct approximate representations of matrices describing the scattering properties of arbitrary objects. The method is based on the implicit evaluation of scattering responses from iteratively…

Computational Physics · Physics 2023-04-19 Johan Lundgren , Kurt Schab , Miloslav Capek , Mats Gustafsson , Lukas Jelinek

Radiative transfer (RT) problems in which the source function includes a scattering-like integral are typical two-points boundary problems. Their solution via differential equations implies to make hypotheses on the solution itself, namely…

Solar and Stellar Astrophysics · Physics 2015-05-30 E. Simonneau , O. Cardona , L. Crivellari

We analyze the inverse problem to reconstruct the shape of a three dimensional homogeneous dielectric obstacle from the knowledge of noisy far field data. The forward problem is solved by a system of second kind boundary integral equations.…

Numerical Analysis · Mathematics 2020-06-22 Thorsten Hohage , Frédérique Le Louër