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Thermal Radiative Transfer (TRT) is the dominant energy transfer mechanism in high-energy density physics with applications in inertial confinement fusion and astrophysics. The stiff interactions between the material and radiation fields…

Computational Physics · Physics 2019-05-01 Hans Hammer , HyeongKae Park , Luis Chacon

Thermal radiative transfer (TRT) presents significant computational challenges due to the stiff, nonlinear coupling between radiation and material energy, particularly in multigroup, high-fidelity transport models. In this work, we develop…

Numerical Analysis · Mathematics 2026-03-24 Samuel Olivier , James S. Warsa , HyeongKae Park

In this paper we present a multilevel projection-based iterative scheme for solving thermal radiative transfer problems that performs iteration cycles on the high-order Boltzmann transport equation (BTE) and low-order moment equations.…

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

This paper presents nonlinear iterative methods for the fundamental thermal radiative transfer (TRT) model defined by the time-dependent multifrequency radiative transfer (RT) equation and the material energy balance (MEB) equation. The…

Numerical Analysis · Mathematics 2024-09-24 Dmitriy Y. Anistratov

The phonon Boltzmann transport equation (BTE) is widely utilized to study non-diffusive thermal transport. We find a solution of the BTE in the thin film transient thermal grating (TTG) experimental geometry by using a recently developed…

Mesoscale and Nanoscale Physics · Physics 2016-07-15 Vazrik Chiloyan , Lingping Zeng , Samuel Huberman , Alexei A. Maznev , Keith A. Nelson , Gang Chen

Neutrino transport and neutrino interactions in dense matter play a crucial role in stellar core collapse, supernova explosions and neutron star formation. Here we present a detailed description of a new numerical code for treating the time…

Astrophysics · Physics 2008-11-26 Markus Rampp , H. -Thomas Janka

The main purpose of this paper is to obtain analytical solutions for radiative transfer equations related to the vertical structure of accretion discs with finite optical depth. In the non-gray atmosphere, we employ the optical-depth…

High Energy Astrophysical Phenomena · Physics 2020-06-24 Maryam Samadi , Fahimeh Habibi , Shahram Abbassi

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

Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion (ICF) applications. The work horse of warm dense…

Photon trapping is believed to be an important mechanism in super-Eddington accretion, which greatly reduces the radiative efficiency as photons are swallowed by the central black hole before they can escape from the accretion flow. This…

High Energy Astrophysical Phenomena · Physics 2023-08-17 Cheng-Liang Jiao

We use our variable Eddington tensor (VET) radiation hydrodynamics code to perform two-dimensional simulations to study the impact of radiation forces on atmospheres composed of dust and gas. Our setup closely follows that of Krumholz &…

Astrophysics of Galaxies · Physics 2015-06-19 Shane W. Davis , Yan-Fei Jiang , James M. Stone , Norman Murray

The fractional advection-dispersion equation (FADE) has attracted increased attention from researchers as it provides an accurate description for challenging phenomenas with long-range time memory and spatial interactions, such as the…

Numerical Analysis · Mathematics 2019-02-12 Huan Liu , Hong Wang , Xiangcheng Zheng

We present high-order, finite element-based Second Moment Methods (SMMs) for solving radiation transport problems in two spatial dimensions. We leverage the close connection between the Variable Eddington Factor (VEF) method and SMM to…

Numerical Analysis · Mathematics 2023-06-19 Samuel Olivier , Terry S. Haut

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

We solve spherically symmetric radiation flows under full special relativity with the help of a variable Eddington factor $f(\tau, \beta)$, where $\tau$ is the optical depth and $\beta$ is the flow velocity normalized by the speed of light.…

Astrophysics · Physics 2015-05-13 Chizuru Akizuki , Jun Fukue

In this paper we develop a framework for moment-based adaptive time integration of deterministic multifrequency thermal radiation transpot (TRT). We generalize our recent semi-implicit-explicit (IMEX) integration framework for gray TRT to…

Numerical Analysis · Mathematics 2026-02-11 Ben S. Southworth , Steven Walton , Steven B. Roberts , HyeongKae Park

A novel method for solving the linear radiative transport equation (RTE) in a three-dimensional homogeneous medium is proposed and illustrated with numerical examples. The method can be used with an arbitrary phase function A(s,s') with the…

Mathematical Physics · Physics 2007-05-23 George Panasyuk , John C. Schotland , Vadim A. Markel

We present conservative 3+1 general relativistic variable Eddington tensor radiation transport equations, including greater elaboration of the momentum space divergence (that is, the energy derivative term) than in previous work. These…

High Energy Astrophysical Phenomena · Physics 2013-07-08 Christian Y. Cardall , Eirik Endeve , Anthony Mezzacappa

The effects of thermal diffuse scattering on the transmission and eventual diffraction of highly accelerated electrons are investigated with a method that incorporates the frozen phonon approximation to the exact numerical solution of the…

Computational Physics · Physics 2018-01-22 S. Rudinsky , A. S. Sanz , R. Gauvin

Reaction-diffusion equations (RDEs) are often derived as continuum limits of lattice-based discrete models. Recently, a discrete model which allows the rates of movement, proliferation and death to depend upon whether the agents are…

Dynamical Systems · Mathematics 2021-05-19 Yifei Li , Peter van Heijster , Matthew J. Simpson , Martin Wechselberger