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Related papers: Equilibrium-diffusion limit of the radiation model

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In this paper, we are concerned with the non-relativistic limit of a class of computable approximation models for radiation hydrodynamics. The models consist of the compressible Euler equations coupled with moment closure approximations to…

Analysis of PDEs · Mathematics 2022-04-18 Zhiting Ma , Wen-An Yong

We derive general formulas for photon and dilepton production rates from an arbitrary non-equilibrated medium from first principles in quantum field theory. At lowest order in the electromagnetic coupling constant, these relate the rates to…

High Energy Physics - Phenomenology · Physics 2009-11-10 Julien Serreau

We study the standard spectral line radiative transfer equation for media consisting of resonant atoms and non-resonant components (the dust grains and the atoms without considered spectral transition). Our goal is to study the intensity…

Astrophysics of Galaxies · Physics 2017-06-21 N. A. Silant'ev , G. A. Alekseeva , V. V. Novikov

We rigorously prove the passage from a Lotka-Volterra reaction-diffusion system towards a cross-diffusion system at the fast reaction limit. The system models a competition of two species, where one species has a more diverse diet than the…

Analysis of PDEs · Mathematics 2021-11-15 Elisabetta Brocchieri , Lucilla Corrias , Helge Dietert , Yong-Jung Kim

We consider a generalization of the Lemaitre-Tolman-Bondi (LTB) solutions by keeping the LTB metric but replacing its dust matter source by an imperfect fluid with anisotropic pressure $\Pi_{ab} $. Assuming that total matter-energy density…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Roberto A. Sussman , Mustapha Ishak

This paper introduces a stabilized finite element scheme for the Cahn--Hilliard cross-diffusion model, which is characterized by strongly coupled mobilities, nonlinear diffusion, and complex cross-diffusion terms. These features pose…

Numerical Analysis · Mathematics 2025-05-08 Boyi Wang , Naresh Kumar , Jinyun Yuan

Similarity solutions to the nonlinear non-equilibrium Marshak wave problem with a time dependent radiation driving source are presented. The radiation transfer model used is the gray, non-equilibrium diffusion approximation in the…

High Energy Astrophysical Phenomena · Physics 2024-01-11 Menahem Krief , Ryan G. McClarren

In this paper we develop tools for observers to use when analysing nebular spectra for temperatures and metallicities, with two goals: to present a new, simple method to calculate equilibrium electron temperatures for collisionally excited…

Astrophysics of Galaxies · Physics 2013-07-18 David C. Nicholls , Michael A. Dopita , Ralph S. Sutherland , Lisa J. Kewley , Ethan Palay

In this paper we consider the equation system describing the motion of the air and the variation of the radiation intensity and the quantity of water droplets in the air, including also the process of water phase transition. Under a…

Analysis of PDEs · Mathematics 2016-10-03 Meryem Benssaad , Hanane Belhireche , Steave C. Selvaduray

This paper provides a full characterization of the value function and solution(s) of an optimal stopping problem for a one-dimensional diffusion with an integral criterion. The results hold under very weak assumptions, namely, the diffusion…

Probability · Mathematics 2017-03-21 Manuel Guerra , Cláudia Nunes , Carlos Oliveira

Starting from a particle model describing self-propelled particles interacting through nematic alignment, we derive a macroscopic model for the particle density and mean direction of motion. We first propose a mean-field kinetic model of…

Mathematical Physics · Physics 2019-10-08 Pierre Degond , Sara Merino-Aceituno

We investigate the thermodynamic limit of Dicke superradiance. We find an expression for the system's density matrix that we can prove is exact in the limit of large atom numbers N. This is in contrast to previously known solutions whose…

Quantum Physics · Physics 2022-07-26 Daniel Malz , Rahul Trivedi , Ignacio Cirac

Cosmic ray nuclei fluxes are expected to be measured with high precision in the near future. For instance, high quality data on the antiproton component could give important clues about the nature of the astronomical dark matter. A very…

Astrophysics · Physics 2008-11-26 D. Maurin , F. Donato , R. Taillet , P. Salati

Radiation dominated accretion disks are likely to be subject to the ``photon bubble'' instability, which may lead to strong density inhomogeneities on scales much shorter than the disk scale height. Such disks -- and magnetized,…

Astrophysics · Physics 2009-11-07 Mateusz Ruszkowski , Mitchell C. Begelman

We obtain uniform in time $L^\infty$-bounds for the solutions to a class of thermo-diffusive systems. The nonlinearity is assumed to be at most sub-exponentially growing at infinity and have a linear behavior near zero.

Analysis of PDEs · Mathematics 2023-04-19 Joonhyun La , Jean-Michel Roquejoffre , Lenya Ryzhik

In this paper, we study the global well-posedness and optimal time decay rates of strong solutions to the diffusion approximation model in radiation hydrodynamics in $\mathbb{R}^3$. This model consists of the full compressible Navier-Stokes…

Analysis of PDEs · Mathematics 2025-08-06 Peng Jiang , Fucai Li , Jinkai Ni

In this paper, we study a parabolic reaction diffusion system with constraints that model biofilm growth. Within a unified framework encompassing multiple numerical schemes, we derive the first general convergence rates for approximating…

Numerical Analysis · Mathematics 2025-11-05 Yahya Alnashri

The diffusion of tungsten in {\alpha}-iron is important for the application of ferritic-iron alloys to thermal power plants. These data, over a wide temperature range across the Curie temperature, have been recently reported. We show that…

Materials Science · Physics 2017-02-01 V. Katsika-Tsigourakou , E. S. Skordas

By combining ab initio quantum mechanics calculation and Drude model, electron temperature and lattice temperature dependent electron thermal conductivity is calculated and implemented into a multiscale model of laser material interaction,…

Computational Physics · Physics 2016-11-07 Pengfei Ji , Yuwen Zhang

We consider a class of particle systems which appear in various applications such as approximation theory, plasticity, potential theory and space-filling designs. The positions of the particles on the real line are described as a global…

Analysis of PDEs · Mathematics 2022-10-05 Patrick van Meurs , Ken'ichiro Tanaka