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In this paper, we develop an efficient asymptotic-preserving (AP) Monte Carlo (MC) method for frequency-dependent radiative transfer equations (RTEs), which is based on the AP-MC method proposed for the gray RTEs in \cite{shi2023efficient}.…

Numerical Analysis · Mathematics 2025-11-06 Yiyang Hong , Yi Shi , Yi Cai , Tao Xiong

We present a formulation and numerical algorithm to extend the scheme for grey radiation magneto-hydrodynamics (MHD) developed by Jiang (2021) to include the frequency dependence via the multi-group approach. The entire frequency space can…

Instrumentation and Methods for Astrophysics · Physics 2022-09-15 Yan-Fei Jiang

We present an asymptotic-preserving (AP) numerical method for solving the three-temperature radiative transfer model, which holds significant importance in inertial confinement fusion. A carefully designedsplitting method is developed that…

Numerical Analysis · Mathematics 2024-03-01 Ruo Li , Weiming Li , Shengtong Liang , Yuehan Shao , Min Tang , Yanli Wang

We develop an asymptotic preserving scheme for the gray radiative transfer equation. Two asymptotic regimes are considered: one is a diffusive regime described by a nonlinear diffusion equation for the material temperature; the other is a…

Numerical Analysis · Mathematics 2019-09-17 Min Tang , Li Wang , Xiaojiang Zhang

Radiative transfer plays a key role in the star formation process. Due to a high computational cost, radiation-hydrodynamics simulations performed up to now have mainly been carried out in the grey approximation. In recent years,…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Matthias González , Neil Vaytet , Benoît Commerçon , Jacques Masson

We present a numerical method for solving the time-independent thermal radiative transfer (TRT) equation or the neutron transport (NT) equation when the opacity or cross-section varies rapidly in energy (frequency). The approach is based on…

Numerical Analysis · Mathematics 2016-12-21 T. S. Haut , C. Ahrens , A. Jonko , R. Lowrie , A. Till

In a medium where the dielectric permittivity is perturbed in the presence of an acoustic wave, optical scattering generates frequency-shifted light. In this paper we consider the inverse problem of recovering the optical properties of this…

Analysis of PDEs · Mathematics 2019-10-14 Francis J. Chung , Jeremy G. Hoskins , John C. Schotland

We present in this paper a multigroup model for radiation hydrodynamics to account for variations of the gas opacity as a function of frequency. The entropy closure model (M1) is applied to multigroup radiation transfer in a radiation…

High Energy Astrophysical Phenomena · Physics 2015-05-27 N. M. H. Vaytet , E. Audit , B. Dubroca , F. Delahaye

This paper presents approximation methods for time-dependent thermal radiative transfer problems in high energy density physics. It is based on the multilevel quasidiffusion method defined by the high-order radiative transfer equation (RTE)…

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

In a recent article the authors showed that the radiative Transfer equations with multiple frequencies and scattering can be formulated as a nonlinear integral system. In the present article, the formulation is extended to handle reflective…

Numerical Analysis · Mathematics 2023-06-12 Olivier Pironneau , Pierre-Henri Tournier

Fractional diffusion equations (FDEs) are a mathematical tool used for describing some special diffusion phenomena arising in many different applications like porous media and computational finance. In this paper, we focus on a…

Numerical Analysis · Mathematics 2017-10-11 Hamid Moghaderi , Mehdi Dehghan , Marco Donatelli , Mariarosa Mazza

In this paper we study the stability of explicit finite difference discretizations of linear advection-diffusion equations (ADE) with arbitrary order of accuracy in the context of method of lines. The analysis first focuses on the stability…

Numerical Analysis · Mathematics 2020-06-17 Xianyi Zeng , Md Mahmudul Hasan

When solving the time-dependent radiative transport equation (RTE), implicit time discretization is often employed for its robustness and stability. This results in a sequence of steady-state RTEs with identical cross-sections but varying…

Numerical Analysis · Mathematics 2026-04-24 Qinchen Song , Lei Zhang , Min Tang

The Fractional Diffusion Equation (FDE) is a mathematical model that describes anomalous transport phenomena characterized by non-local and long-range dependencies which deviate from the traditional behavior of diffusion. Solving this…

Numerical Analysis · Mathematics 2023-11-14 Mohammad Partohaghighi , Emmanuel Asante-Asamani , Olaniyi S. Iyiola

Monotone finite difference methods provide stable convergent discretizations of a class of degenerate elliptic and parabolic Partial Differential Equations (PDEs). These methods are best suited to regular rectangular grids, which leads to…

Numerical Analysis · Mathematics 2015-11-19 Adam M. Oberman , Ian Zwiers

We derive an expansion of the functional renormalization (fRG) equations that treats the frequency and momentum dependencies of the vertices in a systematic manner. The scheme extends the channel-decomposed fRG equations to the frequency…

Strongly Correlated Electrons · Physics 2021-07-07 Nahom K. Yirga , David K. Campbell

Fractional differential equations (FDEs) are an extension of the theory of fractional calculus. However, due to the difficulty in finding analytical solutions, there have not been extensive applications of FDEs until recent decades. With…

Numerical Analysis · Mathematics 2020-07-20 Nirupama Bhattacharya , Gabriel A. Silva

The CFIE used for solving scattering and radiation problems, although a resonance-free formulation, suffers from an ill-conditioning that strongly depends on the frequency and discretization density, both in the low- and high-frequency…

Computational Physics · Physics 2020-04-22 Tiffany L. Chhim , Simon B. Adrian , Francesco P. Andriulli

Discontinuous Galerkin (DG) methods are widely adopted to discretize the radiation transport equation (RTE) with diffusive scalings. One of the most important advantages of the DG methods for RTE is their asymptotic preserving (AP)…

Numerical Analysis · Mathematics 2024-04-17 Cory D. Hauck , Qiwei Sheng , Yulong Xing

Frequency-dependent/hybrid approaches for stellar irradiation are of primary importance in numerical simulations of massive star formation. We seek to compare outflow and accretion mechanisms in star formation simulations. We investigate…

Instrumentation and Methods for Astrophysics · Physics 2020-03-11 R. Mignon-Risse , M. González , B. Commerçon , J. Rosdahl
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