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The inversion of spectropolarimetric observations of the solar upper atmosphere is one of the most challenging goals in solar physics. If we account for all relevant ingredients of the spectral line formation process, such as the…

Solar and Stellar Astrophysics · Physics 2022-03-23 Jiri Stepan , Tanausu del Pino Aleman , Javier Trujillo Bueno

A spectral element method (SEM) is developed to solve polarized radiative transfer in multidimensional participating medium. The angular discretization is based on the discrete-ordinates approach, and the spatial discretization is conducted…

Computational Physics · Physics 2011-05-09 J. M. Zhao , L. H. Liu , P. -f. Hsu , J. Y. Tan

A method is introduced for the construction of meshless discretization schemes which preserve Lie symmetries of the differential equations that these schemes approximate. The method exploits the fact that equivariant moving frames provide a…

Mathematical Physics · Physics 2015-06-11 Alexander Bihlo

The linearly-polarized solar limb spectrum that is produced by scattering processes contains a wealth of information on the physical conditions and magnetic fields of the solar outer atmosphere, but the modeling of many of its strongest…

Solar and Stellar Astrophysics · Physics 2015-05-18 M. Sampoorna , J. Trujillo Bueno

This paper introduces a method to preform optical tomography, using 3D radiative transfer as the forward model. We use an iterative approach predicated on the Spherical Harmonics Discrete Ordinates Method (SHDOM) to solve the optimization…

Atmospheric and Oceanic Physics · Physics 2015-01-27 Aviad Levis , Yoav Y. Schechner , Amit Aides , Anthony B. Davis

Higher resolution telescopes as well as 3D numerical simulations will require the development of detailed 3D radiative transfer calculations. Building upon our previous work we extend our method to include both continuum and line transfer.…

Astrophysics · Physics 2009-11-13 E. Baron , Peter H. Hauschildt

Solving the continuum radiative transfer equation in high opacity media requires sophisticated numerical tools. In order to test the reliability of such tools, we present a benchmark of radiative transfer codes in a 2D disc configuration.…

Solar and Stellar Astrophysics · Physics 2015-05-13 C. Pinte , T. J. Harries , M. Min , A. M. Watson , C. P. Dullemond , P. Woitke , F. Menard , M. C. Duran-Rojas

This paper applies meshless method of lines, which uses radial basis functions (RBFs) as a spatial collocation scheme to solve the Coupled Drinfeld's-Sokolov-Wilson System. Runge-Kutta method is used for time integration of the system of…

Numerical Analysis · Mathematics 2017-03-16 Sirajul Haq , Nagina Hassan , S. I. A. Tirmizi , Muhammad Usman

An iterative method is derived for image reconstruction. Among other attributes, this method allows constraints unrelated to the radiation measurements to be incorporated into the reconstructed image. A comparison is made with the widely…

Computational Physics · Physics 2011-01-06 Clinton DeW. Van Siclen

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 radiative transfer equation is a fundamental equation in transport theory and applications, which is a 5-dimensional PDE in the stationary one-velocity case, leading to great difficulties in numerical simulation. To tackle this…

Numerical Analysis · Mathematics 2022-01-05 Jianguo Huang , Yue Yu

We proposed in a previous paper [Opt. Commun. 228, 33 (2003)] a modified radiative transfer equation to describe radiative transfer in a medium with a spatially varying refractive index. The present paper is devoted to the demonstration…

Optics · Physics 2008-05-23 Jean-Michel Tualle

New high-resolution spectropolarimetric observations of solar prominences require improved radiative modelling capabilities in order to take into account both multi-dimensional - at least 2D - geometry and complex atomic models. This makes…

Astrophysics · Physics 2009-11-13 L. Leger , L. Chevallier , F. Paletou

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

6D pose estimation of textureless objects is a valuable but challenging task for many robotic applications. In this work, we propose a framework to address this challenge using only RGB images acquired from multiple viewpoints. The core…

Robotics · Computer Science 2023-02-23 Jun Yang , Wenjie Xue , Sahar Ghavidel , Steven L. Waslander

This paper develops meshless methods for probabilistically describing discretisation error in the numerical solution of partial differential equations. This construction enables the solution of Bayesian inverse problems while accounting for…

Methodology · Statistics 2017-12-20 Jon Cockayne , Chris Oates , Tim Sullivan , Mark Girolami

We describe a highly flexible framework to solve 3D radiation transfer problems in scattering dominated environments based on a long characteristics piece-wise parabolic formal solution and an operator splitting method. We find that the…

Astrophysics · Physics 2009-11-11 Peter H. Hauschildt , E. Baron

We propose in this work a fast numerical algorithm for solving the equation of radiative transfer (ERT) in isotropic media. The algorithm has two steps. In the first step, we derive an integral equation for the angularly averaged ERT…

Numerical Analysis · Mathematics 2019-07-09 Kui Ren , Rongting Zhang , Yimin Zhong

A full symmetry classification is given for models of energy transport in radiant plasma when the mass density is spatially variable and the diffusivity is nonlinear. A systematic search for conservation laws also leads to some potential…

Mathematical Physics · Physics 2015-06-18 P. Broadbridge , N. M. Ivanova

A discrete spherical harmonics method is developed for the radiative transfer problem in inhomogeneous polarized planar atmosphere illuminated at the top by a collimated sunlight while the bottom reflects the radiation. The method expands…

Instrumentation and Methods for Astrophysics · Physics 2018-02-07 Romuald Tapimo , Hervé Thierry Tagne Kamdem , David Yemele