On the role of tachoclines in solar and stellar dynamos

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dc.creatorGustavo Andres Guerrero Eraso
dc.creatorPiotr Krzysztof Smolarkiewicz
dc.creatorElisabete Maria de Gouveia Dal Pino
dc.creatorAlexander. G. Kosovichev
dc.creatorNagi Nicolas Mansour
dc.date.accessioned2023-10-31T13:05:25Z
dc.date.accessioned2025-09-09T00:27:54Z
dc.date.available2023-10-31T13:05:25Z
dc.date.issued2016
dc.description.sponsorshipCNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
dc.description.sponsorshipFAPESP - Fundação de Amparo à Pesquisa do Estado de São Paulo
dc.format.mimetypepdf
dc.identifier.doihttps://doi.org/10.3847/0004-637X/819/2/104
dc.identifier.issn1538-4357
dc.identifier.urihttps://hdl.handle.net/1843/60312
dc.languageeng
dc.publisherUniversidade Federal de Minas Gerais
dc.relation.ispartofThe Astrophysical Journal
dc.rightsAcesso Aberto
dc.subjectEstrelas
dc.subjectSol
dc.subjectSolar magnetic fields
dc.subjectSolar rotation
dc.subject.otherStars
dc.subject.otherSun
dc.subject.otherSolar and stellar dynamos
dc.titleOn the role of tachoclines in solar and stellar dynamos
dc.typeArtigo de periódico
local.citation.epage17
local.citation.issue2
local.citation.spage1
local.citation.volume819
local.description.resumoRotational shear layers at the boundary between radiative and convective zones, tachoclines, play a key role in the process of magnetic field generation in solar-like stars. We present two sets of global simulations of rotating turbulent convection and dynamo. The first set considers a stellar convective envelope only; the second one, aiming at the formation of a tachocline, also considers the upper part of the radiative zone. Our results indicate that the resulting properties of the mean flows and dynamo, such as the growth rate, saturation energy, and mode, depend on the Rossby number (Ro). For the first set of models either oscillatory (with ∼2 yr period) or steady dynamo solutions are obtained. The models in the second set naturally develop a tachocline, which in turn leads to the generation of a strong mean magnetic field. Since the field is also deposited in the stable deeper layer, its evolutionary timescale is much longer than in the models without a tachocline. Surprisingly, the magnetic field in the upper turbulent convection zone evolves on the same timescale as the deep field. These models result in either an oscillatory dynamo with a ∼30 yr period or a steady dynamo depending on Ro. In terms of the mean-field dynamo coefficients computed using the first-order smoothing approximation, the field evolution in the oscillatory models without a tachocline seems to be consistent with dynamo waves propagating according to the Parker–Yoshimura sign rule. In the models with tachoclines the dynamics is more complex and involves other transport mechanisms as well as tachocline instabilities.
local.identifier.orcidhttps://orcid.org/0000-0002-2671-8796
local.identifier.orcidhttps://orcid.org/0000-0001-7077-3285
local.identifier.orcidhttps://orcid.org/0000-0001-8058-4752
local.identifier.orcidhttps://orcid.org/0000-0002-3927-3917
local.publisher.countryBrasil
local.publisher.departmentICX - DEPARTAMENTO DE FÍSICA
local.publisher.initialsUFMG
local.url.externahttps://iopscience.iop.org/article/10.3847/0004-637X/819/2/104

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