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Asymptotic radiative transfer (ART), like diffusion theory, assumes the angular intensity distribution incident at a boundary is identical with that in the depth of the scattering medium. However, the asymptotic intensity profile and…

Optics · Physics 2019-05-06 Adrian Selden

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

The thermal radiative transfer equations model temperature evolution through a background medium as a result of radiation. When a large number of particles are absorbed in a short time scale, the dynamics tend to a non-linear diffusion-type…

Numerical Analysis · Mathematics 2025-03-03 Chinmay Patwardhan , Martin Frank , Jonas Kusch

We study the approximation of the radiative transfer equation with a relatively few moments in the spherically symmetric case. We propose a three-moment model based on choosing the beta distribution as the ansatz for the specific intensity.…

Computational Physics · Physics 2020-01-01 Ruo Li , Weiming Li , Lingchao Zheng

The Active Flux (AF) method is a compact, high-order finite volume scheme that enhances flexibility by introducing point values at cell interfaces as additional degrees of freedom alongside cell averages. The method of lines is employed…

Numerical Analysis · Mathematics 2025-08-08 Junming Duan , Wasilij Barsukow , Christian Klingenberg

The present paper introduces an efficient and accurate numerical scheme for the solution of a highly anisotropic elliptic equation, the anisotropy direction being given by a variable vector field. This scheme is based on an asymptotic…

Numerical Analysis · Mathematics 2014-04-08 Pierre Degond , Fabrice Deluzet , Alexei Lozinski , Jacek Narski , Claudia Negulescu

In the article, new asymptotic approximation of the $n$th order is obtained and proposed to be used in calculations of radiation propagation without scattering in optically thick media; the asymptotic approximation is much simpler and more…

Instrumentation and Methods for Astrophysics · Physics 2020-12-23 S. A. Serov , S. S. Serova

This paper is concerned with the numerical approximation of the isothermal Euler equations for charged particles subject to the Lorentz force. When the magnetic field is large, the so-called drift-fluid approximation is obtained. In this…

Mathematical Physics · Physics 2014-04-08 Pierre Degond , Fabrice Deluzet , Afeintou Sangam , Marie-Hélène Vignal

The method of asymptotic normalization coefficients is a standard approach for studies of two-body non-resonant radiative capture processes in nuclear astrophysics. This method suggests a fully analytical description of the radiative…

Nuclear Theory · Physics 2020-12-02 L. V. Grigorenko , Yu. L. Parfenova , N. B. Shulgina , M. V. Zhukov

We propose and analyze a new asymptotic preserving (AP) finite volume scheme for the multidimensional compressible barotropic Euler equations to simulate low Mach number flows. The proposed scheme uses a stabilized upwind numerical flux,…

Numerical Analysis · Mathematics 2024-07-19 K. R. Arun , Amogh Krishnamurthy , Mária Lukáčová-Medvid'ová

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

We present a positive and asymptotic preserving numerical scheme for solving linear kinetic, transport equations that relax to a diffusive equation in the limit of infinite scattering. The proposed scheme is developed using a standard…

Numerical Analysis · Mathematics 2018-07-18 M. Paul Laiu , Martin Frank , Cory D. Hauck

Simple finite differencing of the anisotropic diffusion equation, where diffusion is only along a given direction, does not ensure that the numerically calculated heat fluxes are in the correct direction. This can lead to negative…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Prateek Sharma , Gregory W. Hammett

In this work, high order asymptotic preserving schemes are constructed and analysed for kinetic equations under a diffusive scaling. The framework enables to consider different cases: the diffusion equation, the advection-diffusion equation…

Numerical Analysis · Mathematics 2023-05-24 Megala Anandan , Benjamin Boutin , Nicolas Crouseilles

This paper presents a hybrid numerical method to solve efficiently a class of highly anisotropic elliptic problems. The anisotropy is aligned with one coordinate-axis and its strength is described by a parameter $\eps \in (0,1]$, which can…

Numerical Analysis · Mathematics 2015-11-04 Anais Crestetto , Fabrice Deluzet , Claudia Negulescu

We apply the concept of Asymptotic Preserving (AP) schemes to the linearized p-system and discretize the resulting elliptic equation using standard continuous Finite Elements instead of Finite Differences. The fully discrete method is…

Numerical Analysis · Mathematics 2014-06-17 Jochen Schütz

The electric potential is an essential quantity for the confinement process of tokamak plasmas, with important impact on the performances of fusion reactors. Understanding its evolution in the peripheral region - the part of the plasma…

Plasma Physics · Physics 2018-07-04 Andrea Mentrelli , Claudia Negulescu

The thermal radiative transfer (TRT) equations form an integro-differential system that describes the propagation and collisional interactions of photons. Computing accurate and efficient numerical solutions TRT are challenging for several…

Numerical Analysis · Mathematics 2021-11-09 Ryan G. McClarren , James A. Rossmanith , Minwoo Shin

We propose an adiabatic method for optimal phonon temperature estimation using trapped ions which can be operated beyond the Lamb-Dicke regime. The quantum sensing technique relies on a time-dependent red-sideband transition of phonon…

Quantum Physics · Physics 2021-03-24 Aleksandrina V. Kirkova , Weibin Li , Peter A. Ivanov

Thermal radiative transfer (TRT) is an essential piece of physics in inertial confinement fusion, high-energy density physics, astrophysics etc. The physical models of this type of problem are defined by strongly coupled differential…

Numerical Analysis · Mathematics 2025-08-06 Dmitriy Y. Anistratov , Terry S. Haut