Improved near optimal angular quadratures for polarised radiative transfer in 3D MHD models

0548082 - ASÚ 2022 RIV FR eng J - Journal Article
Jaume Bestard, J. - Štěpán, Jiří - Trujillo Bueno, J.
Improved near optimal angular quadratures for polarised radiative transfer in 3D MHD models.
Astronomy & Astrophysics. Roč. 645, January (2021), č. článku A101. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA ČR(CZ) GA19-20632S
Institutional support: RVO:67985815
Keywords : numerical methods * polarization * radiative transfer
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.240, year: 2021
Method of publishing: Open access with time embargo
https://doi.org/10.1051/0004-6361/202039424

Accurate angular quadratures are crucial for the numerical solution of three-dimensional (3D) radiative transfer problems, especially when the spectral line polarisation produced by the scattering of anisotropic radiation is included. There are two requirements for obtaining an optimal quadrature and they are difficult to satisfy simultaneously: high accuracy and short computing time. By imposing certain symmetries, we were recently able to derive a set of near optimal angular quadratures. Here, we extend our previous investigation by considering other symmetries. Moreover, we test the performance of our new quadratures by numerically solving a radiative transfer problem of resonance line polarisation in a 3D model of the solar atmosphere resulting from a magneto-hydrodynamical simulation. The new angular quadratures derived here outperform the previous ones in terms of the number of rays needed to achieve any given accuracy.
Permanent Link: http://hdl.handle.net/11104/0324237