Numerical solutions to linear transfer problems of polarized radiation III. Parallel preconditioned Krylov solver tailored for modeling PRD effects

dc.bibliographicCitation.firstPageA197
dc.bibliographicCitation.journalTitleAstronomy & Astrophysicseng
dc.bibliographicCitation.volume664
dc.contributor.authorBenedusi, Pietro
dc.contributor.authorJanett, Gioele
dc.contributor.authorRiva, Simone
dc.contributor.authorKrause, Rolf
dc.contributor.authorBelluzzi, Luca
dc.date.accessioned2023-02-10T09:22:54Z
dc.date.available2023-02-10T09:22:54Z
dc.date.issued2022
dc.description.abstractContext. The polarization signals produced by the scattering of anistropic radiation in strong resonance lines encode important information about the elusive magnetic fields in the outer layers of the solar atmosphere. An accurate modeling of these signals is a very challenging problem from the computational point of view, in particular when partial frequency redistribution (PRD) effects in scattering processes are accounted for with a general angle-dependent treatment. Aims. We aim at solving the radiative transfer problem for polarized radiation in nonlocal thermodynamic equilibrium conditions, taking angle-dependent PRD effects into account. The problem is formulated for a two-level atomic model in the presence of arbitrary magnetic and bulk velocity fields. The polarization produced by scattering processes and the Zeeman effect is considered. Methods. The proposed solution strategy is based on an algebraic formulation of the problem and relies on a convenient physical assumption, which allows its linearization. We applied a nested matrix-free GMRES iterative method. Effective preconditioning is obtained in a multifidelity framework by considering the light-weight description of scattering processes in the limit of complete frequency redistribution (CRD). Results. Numerical experiments for a one-dimensional (1D) atmospheric model show near optimal strong and weak scaling of the proposed CRD-preconditioned GMRES method, which converges in few iterations, independently of the discretization parameters. A suitable parallelization strategy and high-performance computing tools lead to competitive run times, providing accurate solutions in a few minutes. Conclusions. The proposed solution strategy allows the fast systematic modeling of the scattering polarization signals of strong resonance lines, taking angle-dependent PRD effects into account together with the impact of arbitrary magnetic and bulk velocity fields. Almost optimal strong and weak scaling results suggest that this strategy is applicable to realistic 3D models. Moreover, the proposed strategy is general, and applications to more complex atomic models are possible.eng
dc.description.versionpublishedVersioneng
dc.identifier.urihttps://oa.tib.eu/renate/handle/123456789/11397
dc.identifier.urihttp://dx.doi.org/10.34657/10431
dc.language.isoeng
dc.publisherLes Ulis : EDP Sciences
dc.relation.doihttps://doi.org/10.1051/0004-6361/202243059
dc.relation.essn1432-0746
dc.relation.issn0004-6361
dc.rights.licenseCC BY 4.0 Unported
dc.rights.urihttps://creativecommons.org/licenses/by/4.0
dc.subject.ddc520
dc.subject.otherpolarizationeng
dc.subject.otherradiative transfereng
dc.subject.otherscatteringeng
dc.subject.otherstars: atmosphereseng
dc.subject.otherSun: atmosphereeng
dc.titleNumerical solutions to linear transfer problems of polarized radiation III. Parallel preconditioned Krylov solver tailored for modeling PRD effectseng
dc.typeArticleeng
dc.typeTexteng
tib.accessRightsopenAccess
wgl.contributorKIS
wgl.subjectPhysikger
wgl.typeZeitschriftenartikelger
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