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We introduce a (linear) positive and asymptotic preserving method or solving the one-group radiation transport equation. The approximation in space is discretization agnostic: the space approximation can be done with continuous or…

Numerical Analysis · Mathematics 2019-05-10 Jean-Luc Guermond , Bojan Popov , Jean Ragusa

A meshless method is presented to solve the radiative transfer equation in the even parity formulation of the discrete ordinates method in complex 2D and 3D geometries. Prediction results of radiative heat transfer problems obtained by the…

Computational Physics · Physics 2018-07-10 Cheng-An Wang , Hamou Sadat , Vital Le dez , Denis Lemonnier

We consider the numerical solution of the optimal transport problem between densities that are supported on sets of unequal dimension. Recent work by McCann and Pass reformulates this problem into a non-local Monge-Amp\`ere type equation.…

Numerical Analysis · Mathematics 2023-07-14 Matthew A. Cassini , Brittany Froese Hamfeldt

Highly precise numerical solutions to the radiative transfer equation with polarization present a special challenge. Here, we establish a precise numerical solution to the radiative transfer equation with combined Rayleigh and isotropic…

Classical Physics · Physics 2018-03-14 B. D. Ganapol

The analytic solution for the two-streams discrete ordinates equations is carried out on the spatial domain in one-dimensional spherical geometry. The solution satisfies all the physical and the geometric conditions, namely: the natural…

Astrophysics · Physics 2007-05-23 Charles H Aboughantous

Highly sensitive, non-destructive, real-time spectroscopic determination of the 2D kinetic momentum distribution of a cold-atom sample is performed with the three-beam measurement of the recoil-induced resonances. The measurements performed…

Atomic Physics · Physics 2009-11-11 Maria Brzozowska , Tomasz M. Brzozowski , Jerzy Zachorowski , Wojciech Gawlik

The radiation transport equation is a mesoscopic equation in high dimensional phase space. Moment methods approximate it via a system of partial differential equations in traditional space-time. One challenge is the high computational…

Computational Physics · Physics 2020-04-07 Marco Berghoff , Martin Frank , Benjamin Seibold

We consider general reaction diffusion systems posed on rectangular lattices in two or more spatial dimensions. We show that travelling wave solutions to such systems that propagate in rational directions are nonlinearly stable under small…

Analysis of PDEs · Mathematics 2014-10-28 A. Hoffman , H. J. Hupkes , E. Van Vleck

In order to choose a numerical method for solving the time dependent equations of radiative transport, we obtain an exact solution for the time dependent radiation field in a one dimensional infinite medium with monochromatic, isotropic…

Astrophysics · Physics 2009-11-13 D. I. Nagirner , S. L. Kirusheva

This paper concerns the kinetic limit of the Dirac equation with random electromagnetic field. We give a detailed mathematical analysis of the radiative transport limit for the phase space energy density of solutions to the Dirac equation.…

Analysis of PDEs · Mathematics 2012-10-15 Yu Gu , Guillaume Bal

In this paper, we develop several related finite dimensional variational principles for discrete optimal transport (DOT), Minkowski type problems for convex polytopes and discrete Monge-Ampere equation (DMAE). A link between the discrete…

Geometric Topology · Mathematics 2013-02-25 Xianfeng Gu , Feng Luo , Jian Sun , S. -T. Yau

We discuss the efficiency of Monte Carlo methods in solving continuum radiative transfer problems. The sampling of the radiation field and convergence of dust temperature calculations in the case of optically thick clouds are both studied.…

Astrophysics · Physics 2009-11-10 M. Juvela

An integro-differential equation describing the angular distribution of beams is analyzed for a medium with random inhomogeneities. Beams are trapped because inhomogeneities give rise to wave localization at random locations and random…

Instrumentation and Methods for Astrophysics · Physics 2011-11-15 Aleksander Stanislavsky

We simulate convection near the solar surface, where the continuum optical depth is of order unity. Hence, to determine the radiative heating and cooling in the energy conservation equation, we must solve the radiative transfer equation…

Astrophysics · Physics 2007-05-23 Robert Stein , Aake Nordlund

We consider radiation transport theory applied to non-dispersive but refractive media. This setting is used to discuss Minkowski's and Abraham's electromagnetic momentum, and to derive conservation equations independent of the choice of…

Astrophysics · Physics 2009-11-10 Mattias Marklund

We give a new probabilistic construction of solutions to real Monge-Amp\`ere equations in R^n satisfying the second boundary value problem with respect to a given target convex body P) which fits naturally into the theory of optimal…

Analysis of PDEs · Mathematics 2013-02-19 Robert J. Berman

We study a random matching problem on closed compact $2$-dimensional Riemannian manifolds (with respect to the squared Riemannian distance), with samples of random points whose common law is absolutely continuous with respect to the volume…

Probability · Mathematics 2026-05-01 Nicolas Clozeau , Francesco Mattesini

Radiative transfer is essential in astronomy, both for interpreting observations and simulating various astrophysical phenomena. However, self-consistent line radiative transfer is computationally expensive, especially in 3D. To reduce the…

Instrumentation and Methods for Astrophysics · Physics 2025-05-14 Thomas Ceulemans , Frederik De Ceuster , Leen Decin

In this paper, we study relative metric regularity of set-valued mappings with emphasis on directional metric regularity. We establish characterizations of relative metric regularity without assuming the completeness of the image spaces, by…

Optimization and Control · Mathematics 2013-04-30 Huynh Van Ngai , Michel A. Théra

Thermal radiation transport is a challenging problem in computational physics that has long been approached primarily in one of a few standard ways: approximate moment methods (for instance P$_1$ or M$_1$), implicit Monte Carlo, discrete…

Instrumentation and Methods for Astrophysics · Physics 2026-02-04 J. C. Dolence , H. R. Hammer , H. Park , B. Prather , B. R. Ryan , R. T. Wollaeger