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Related papers: Fast multilevel radiative transfer

200 papers

Analytical and numerical solutions are obtained for the equation of radiative transfer in ultra-relativistic opaque jets. The solution describes the initial trapping of radiation, its adiabatic cooling, and the transition to transparency.…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Andrei M. Beloborodov

We present a general method to calculate radiative transfer including scattering in the continuum as well as in lines in spherically symmetric systems that are influenced by the effects of general relativity (GR). We utilize a comoving…

Astrophysics · Physics 2009-11-11 S. Knop , P. H. Hauschildt , E. Baron

We derive new equations using the mixed-frame approach for one- and two-dimensional (axisymmetric) time-dependent radiation transport and the associated couplings with matter. Our formulation is multi-group and multi-angle and includes…

Astrophysics · Physics 2011-02-11 Ivan Hubeny , Adam Burrows

We present a new radiative transfer code for axi-symmetric stellar atmospheres and compare test results against 1D and 2D models with and without velocity fields. The code uses the short characteristic method with modifications to handle…

Astrophysics · Physics 2009-11-11 J. Zsargo , D. J. Hillier , L. N. Georgiev

This paper develops a strong computational approach to simulate a three-dimensional nonlinear radiation-conduction model in optically thick media, subject to suitable initial and boundary conditions. The space derivatives are approximated…

Numerical Analysis · Mathematics 2026-01-01 Eric Ngondiep

The exponential growth of astronomical data from large-scale surveys has created both opportunities and challenges for the astrophysics community. This paper explores the possibilities offered by transfer learning techniques in addressing…

Context. Magnetic fields are important to the dynamics of many astrophysical processes and can typically be studied through polarization observations. Polarimetric interferometry capabilities of modern (sub)millimeter telescope facilities…

Instrumentation and Methods for Astrophysics · Physics 2020-04-08 Boy Lankhaar , Wouter Vlemmings

We develop a formalism for calculating the distribution of the axial quadrupole operator in the laboratory frame within the rotationally invariant framework of the configuration-interaction shell model. The calculation is carried out using…

Nuclear Theory · Physics 2018-01-31 C. N. Gilbreth , Y. Alhassid , G. F. Bertsch

On the basis of the method of iterative summation of path integrals (ISPI), we develop a numerically exact transfer-matrix method to describe the nonequilibrium properties of interacting quantum-dot systems. For this, we map the ISPI scheme…

Mesoscale and Nanoscale Physics · Physics 2022-11-01 Simon Mundinar , Alexander Hahn , Jürgen König , Alfred Hucht

Computer simulations of photon transport through an absorbing and/or scattering medium form an important research tool in astrophysics. Nearly all software codes performing such simulations for three-dimensional geometries employ the Monte…

Instrumentation and Methods for Astrophysics · Physics 2018-07-25 Peter Camps , Maarten Baes

Accurate radiative transfer coefficients (emissivities, absorptivities, and rotativities) are needed for modeling radiation from relativistically hot, magnetized plasmas such as those found in Event Horizon Telescope sources. Here we…

High Energy Astrophysical Phenomena · Physics 2021-11-03 Andrew Marszewski , Ben S. Prather , Abhishek V. Joshi , Alex Pandya , Charles F. Gammie

Although near-field radiative heat transfer was introduced in the 1950's, interest in the field has recently revived, as the effect promises improved performance in various applications where contactless temperature regulation in the…

Optics · Physics 2023-03-22 Mariano Pascale , Maxime Giteau , Georgia T. Papadakis

We show that mid infrared transmission spectroscopy of a quantum cascade laser provides clear cut information on changes in charge location at different bias. Theoretical simulations of the evolution of the gain/absorption spectrum for the…

Mesoscale and Nanoscale Physics · Physics 2007-12-05 R. Nelander , A. Wacker , M. F. Pereira , D. G. Revin , M. R. Soulby , L. R. Wilson , J. W. Cockburn , A. B. Krysa , J. S. Roberts , R. J. Airey

We analyze theoretically and experimentally how nonlinear differential-transmission spectroscopy of a lambda-system medium can provide quantitative understanding of the optical dipole moments and transition energies. We focus on the…

Materials Science · Physics 2015-01-07 J. P. de Jong , A. R. Onur , D. Reuter , A. D. Wieck , C. H. van der Wal

Exact expressions for all the steady-state fields (E, H, D, B) in uniaxial linear media composed of an arbitrary number of layers having arbitrary thicknesses subjected to normal incidence are derived. Generic boundary condition relations…

Materials Science · Physics 2007-05-23 Pieder Beeli

The nonlinear absorption of laser radiation of relativistic intensities in the underdense plasma by a mechanism of stimulated bremsstrahlung of electrons on the ions/nuclei is investigated in the low frequency approximation. Coefficient of…

Atomic Physics · Physics 2013-05-03 H. K. Avetissian , A. G. Ghazaryan , G. F. Mkrtchian

We present two new accurate and efficient method to compute the formal solution of the polarized radiative transfer equation. In this work, the source function and the absorption matrix are approximated using quadratic and cubic Bezier…

Solar and Stellar Astrophysics · Physics 2015-06-12 J. de la Cruz Rodríguez , N. Piskunov

In the presence of an intensive laser field the radiative recombination of the continuum electron into an atomic bound state generally is accompanied by absorption or emission of several laser quanta. The spectrum of emitted photons…

Atomic Physics · Physics 2009-10-31 M. Yu. Kuchiev , V. N. Ostrovsky

A numerical scheme is proposed for the solution of the three-dimensional radiative transfer equation with variable optical depth. We show that time-dependent ray tracing is an attractive choice for simulations of astrophysical ionization…

Astrophysics · Physics 2009-10-31 Alexei Razoumov , Douglas Scott

Rabi frequencies for multiphoton absorption by atoms or molecules that can be characterized as two- or three-level systems are obtained in the cases of single and double laser perturbations. If the ambiguity in the origin of absolute energy…

Quantum Physics · Physics 2007-05-23 Pedro F. Gonzalez-Diaz