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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

This article presents an on-line tool (rttools.irap.omp.eu) and its accompanying software ressources for the numerical solution of basic radiation transfer out of local thermodynamic equilibrium (LTE). State-of-the-art stationary iterative…

Instrumentation and Methods for Astrophysics · Physics 2015-12-09 J. Lambert , F. Paletou , E. Josselin , J. -M. Glorian

A new method for the formal solution of the 2D radiative transfer equation in axial symmetry in the presence of arbitrary velocity fields is presented. The combination of long and short characteristics methods is used to solve the radiative…

Astrophysics · Physics 2016-08-16 D. Korčáková , J. Kubát

We present a conservative numerical method for radiation magnetohydrodynamics with frequency-dependent full transport in stationary spacetimes. This method is stable and accurate for both large and small optical depths and radiation…

High Energy Astrophysical Phenomena · Physics 2020-03-18 Benjamin R. Ryan , Joshua C. Dolence

We present a new implementation of radiation hydrodynamics (RHD) in the adaptive mesh refinement (AMR) code RAMSES. The multi-group radiative transfer (RT) is performed on the AMR grid with a first-order Godunov method using the M1 closure…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Joakim Rosdahl , Jeremy Blaizot , Dominique Aubert , Timothy Stranex , Romain Teyssier

This paper presents a new technique for developing reduced-order models (ROMs) for nonlinear radiative transfer problems in high-energy density physics. The proper orthogonal decomposition (POD) of photon intensities is applied to obtain…

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

We use the transfer equation in relativistic form to develop an expansion of the one-photon distribution for a medium with constant photon mean free path, $\epsilon$. The resulting radiative viscosity tensor may be expressed either as a…

Astrophysics · Physics 2009-10-31 Xinzhong Chen , Edward A. Spiegel

Transfer matrix method is a well-known and extensively used tool to compute the reflection and transmission coefficients of electromagnetic waves when interacting with a system of layers parallel to each other. We present here a modified…

Optics · Physics 2017-03-14 Srinivas Ganganagunta

Radiative transfer is a fundamental process in astrophysics, essential for both interpreting observations and modeling thermal and dynamical feedback in simulations via ionizing radiation and photon pressure. However, numerically solving…

Instrumentation and Methods for Astrophysics · Physics 2025-11-12 Rune Rost , Lorenzo Branca , Tobias Buck

We present the first extension of the special-relativistic Lattice-Boltzmann Method for radiative transport developed by Weih et al. (2020), to solve the radiative-transfer equation in curved spacetimes. The novel approach is based on the…

General Relativity and Quantum Cosmology · Physics 2025-02-26 Tom Olsen , Luciano Rezzolla

A new means of incorporating radiative transfer into smoothed particle hydrodynamics (SPH) is introduced, which builds on the success of two previous methods - the polytropic cooling approximation as devised by Stamatellos et al (2007), and…

Astrophysics · Physics 2009-11-13 Duncan Forgan , Ken Rice , Dimitris Stamatellos , Anthony Whitworth

Optical diffraction tomography (ODT) is a three-dimensional (3D) label-free imaging technique. The 3D refractive index distribution of a sample can be reconstructed from multiple two-dimensional optical field images via ODT. Herein, we…

Optics · Physics 2021-02-03 Chansuk Park , Kyeoreh Lee , Yoonseok Baek , Yongkeun Park

We present a new numerical approach that is able to solve the multi-dimensional radiative transfer equations in all opacity regimes on a Lagrangian, unstructured network of characteristics based on a stochastic point process. Our method…

Astrophysics · Physics 2007-05-23 Jelle Ritzerveld , Vincent Icke , Erik-Jan Rijkhorst

We describe a novel technique to characterize ultrashort electron bunches in X-ray Free-Electron Lasers. Namely, we propose to use coherent Optical Transition Radiation to measure three-dimensional (3D) electron density distributions. Our…

This paper presents a neural network approach for solving two-dimensional optical tomography (OT) problems based on the radiative transfer equation. The mathematical problem of OT is to recover the optical properties of an object based on…

Computational Physics · Physics 2019-10-14 Yuwei Fan , Lexing Ying

Many naturally-occuring models in the sciences are well-approximated by simplified models, using multiscale techniques. In such settings it is natural to ask about the relationship between inverse problems defined by the original problem…

Numerical Analysis · Mathematics 2019-02-28 Kit Newton , Qin Li , Andrew Stuart

The 21-cm hyperfine line of neutral hydrogen is a useful tool to probe the conditions of the Universe during the Dark Ages, Cosmic Dawn, and the Epoch of Reionisation. In most of the current calculations, the 21-cm line signals at given…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-23 Jennifer Y. H. Chan , Qin Han , Kinwah Wu , Jason D. McEwen

We introduce non-equilibrium molecular hydrogen chemistry into the radiation hydrodynamics code Ramses-RT. This is an adaptive mesh refinement grid code with radiation hydrodynamics that couples the thermal chemistry of hydrogen and helium…

Astrophysics of Galaxies · Physics 2018-09-07 Sarah Nickerson , Romain Teyssier , Joakim Rosdahl

Employing tight-binding approximation we derive a transfer matrix formalism for one-dimensional single photon transport through a composite scattering center, which consists of parallel connected resonator optical waveguides. By solving the…

Quantum Physics · Physics 2017-03-29 Yu Jiang , M. Lozada-Cassou

We demonstrate a technique for transferring $^{226}$Ra atoms from a 3-dimensional magneto-optical-trap (MOT) into a standing wave optical dipole trap (ODT) in an adjacent chamber. The resulting small trapping volume (120 $\mu$m in diameter)…