The Effect of Toroidal Magnetic Fields on Solar Oscillation Frequencies

dc.bibliographicCitation.firstPage74
dc.bibliographicCitation.issue1
dc.bibliographicCitation.volume854
dc.contributor.authorKiefer, René
dc.contributor.authorRoth, Markus
dc.date.accessioned2023-01-24T08:05:50Z
dc.date.available2023-01-24T08:05:50Z
dc.date.issued2018
dc.description.abstractSolar oscillation frequencies change with the level of magnetic activity. Localizing subsurface magnetic field concentrations in the Sun with helioseismology will help us to understand the solar dynamo. Because the magnetic fields are not considered in standard solar models, adding them to the basic equations of stellar structure changes the eigenfunctions and eigenfrequencies. We use quasi-degenerate perturbation theory to calculate the effect of toroidal magnetic fields on solar oscillation mean multiplet frequencies for six field configurations. In our calculations, we consider both the direct effect of the magnetic field, which describes the coupling of modes, and the indirect effect, which accounts for changes in stellar structure due to the magnetic field. We limit our calculations to self-coupling of modes. We find that the magnetic field affects the multiplet frequencies in a way that depends on the location and the geometry of the field inside the Sun. Comparing our theoretical results with observed shifts, we find that strong tachocline fields cannot be responsible for the observed frequency shifts of p modes over the solar cycle. We also find that part of the surface effect in helioseismic oscillation frequencies might be attributed to magnetic fields in the outer layers of the Sun. The theory presented here is also applicable to models of solar-like stars and their oscillation frequencies.eng
dc.description.versionpublishedVersioneng
dc.identifier.urihttps://oa.tib.eu/renate/handle/123456789/10975
dc.identifier.urihttp://dx.doi.org/10.34657/10001
dc.language.isoeng
dc.publisherLondon : Institute of Physics Publ.
dc.relation.doihttps://doi.org/10.3847/1538-4357/aaa3f7
dc.relation.essn1538-4357
dc.relation.ispartofseriesThe astrophysical journal : an international review of spectroscopy and astronomical physics : Part 1 854 (2018), Nr. 1
dc.rights.licenseCC BY 3.0 Unported
dc.rights.urihttps://creativecommons.org/licenses/by/3.0
dc.subjectasteroseismologyeng
dc.subjectdynamoeng
dc.subjectmethods: analyticaleng
dc.subjectmethods: numericaleng
dc.subjectSun: helioseismologyeng
dc.subjectSun: magnetic fieldseng
dc.subject.ddc520
dc.titleThe Effect of Toroidal Magnetic Fields on Solar Oscillation Frequencieseng
dc.typearticle
dc.typeText
dcterms.bibliographicCitation.journalTitleThe astrophysical journal : an international review of spectroscopy and astronomical physics : Part 1
tib.accessRightsopenAccess
wgl.contributorKIS
wgl.subjectPhysikger
wgl.typeZeitschriftenartikelger
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