J/A+A/636/A24   Polarised radiative transfer angular quadratures (Stepan+, 2020)
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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        (SIMBAD/NED BibCode)
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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

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(End)                                        Patricia Vannier [CDS]  12-Mar-2020
