J/A+A/636/A24 Polarised radiative transfer angular quadratures (Stepan+, 2020)
Near optimal angular quadratures for polarised radiative transfer.
Stepan J., Jaume Bestard J., Trujillo Bueno J.
<Astron. Astrophys. 636, A24 (2020)>
=2020A&A...636A..24S 2020A&A...636A..24S (SIMBAD/NED BibCode)
ADC_Keywords: Polarization
Keywords: methods: numerical - polarisation - radiative transfer
Abstract:
In three-dimensional (3D) radiative transfer (RT) problems, the tensor
product quadratures are generally not optimal in terms of the number
of discrete ray directions needed for a given accuracy of the angular
integration of the radiation field. In this paper, we derive a new set
of angular quadrature rules that are more suitable for solving 3D RT
problems with the short- and long-characteristics formal solvers.
These quadratures are more suitable than the currently used ones for
the numerical calculation of the radiation field tensors that are
relevant in the problem of the generation and transfer of polarised
radiation without assuming local thermodynamical equilibrium
(non-LTE). We show that our new quadratures can save up to about 30%
of computing time with respect to the Gaussian-trapezoidal product
Description:
Quadrature for unpolarised and polarised radiations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
il3n1.dat 47 1 *Quadrature for unpolarised radiation,
Unpolarised case for L=3 and n=1
il7n3.dat 64 3 *Quadrature for unpolarised radiation,
Unpolarised case for L=7 and n=3
il9n6.dat 64 6 *Quadrature for unpolarised radiation,
Unpolarised case for L=9 and n=6
il11n7.dat 64 7 *Quadrature for unpolarised radiation,
Unpolarised case for L=11 and n=7
il13n10.dat 64 10 *Quadrature for unpolarised radiation,
Unpolarised case for L=13 and n=10
il15n11.dat 64 11 *Quadrature for unpolarised radiation,
Unpolarised case for L=15 and n=11
iql3n3.dat 64 3 *Quadrature for polarised radiation,
Polarised case for L=3 and n=3
iql5n4.dat 64 4 *Quadrature for polarised radiation,
Polarised case for L=5 and n=4
iql7n7.dat 64 7 *Quadrature for polarised radiation,
Polarised case for L=7 and n=7
iql9n8.dat 64 8 *Quadrature for polarised radiation,
Polarised case for L=9 and n=8
iql11n11.dat 64 11 *Quadrature for polarised radiation,
Polarised case for L=11 and n=11
iql13n14.dat 64 14 *Quadrature for polarised radiation,
Polarised case for L=13 and n=13
iql15n18.dat 64 18 *Quadrature for polarised radiation,
Polarised case for L=15 and n=18
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Note on *.dat:
LX: quadrature for the order L=X, nY: quadrature with n=Y rays per octant.
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Byte-by-byte Description of file: *.dat
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Bytes Format Units Label Explanations
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1- 20 F20.18 --- weight Normalized weights over the whole sphere
22- 42 F21.18 deg incl Inclination measured from the positive Z-axis
44- 64 F21.18 deg azim Azimuth measured from the positive X-axis
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 12-Mar-2020