Meridional flow of small photospheric magnetic features

Komm, R.; Howard, Robert F.; Harvey, J. W.

doi:10.1007/bf00690713

Cited by 255 publications

(200 citation statements)

References 19 publications

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“…The modeled meridional flows are poleward near the solar surface with a velocity of about 10-20m s −1 , in accordance with direct observations of the motion of small magnetic features (e.g. Komm, Howard & Harvey 1993) or inferences from local helioseismology (Giles et al 1997). Two geometries are studied: a single-cell structure with an equatorward return flow in the tachocline, and a double-cell structure with a poleward return flow in the tachocline and a null node at about r = 0.85r .…”

Section: Fast Tachocline Diffusion Modelssupporting

confidence: 87%

Magnetic confinement of the solar tachocline

Garaud¹

2007

The Solar Tachocline

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Two distinct classes of magnetic confinement models exist for the solar tachocline. The "slow tachocline" models are associated with a large-scale primordial field embedded in the radiative zone. The "fast tachocline" models are associated with an overlying dynamo field. I describe the results obtained in each case, their pros and cons, and compare them with existing solar observations. I conclude by discussing new lines of investigation that should be pursued, as well as some means by which these models could be unified or reconciled.

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Section: Fast Tachocline Diffusion Modelssupporting

confidence: 87%

Magnetic confinement of the solar tachocline

Garaud¹

2007

The Solar Tachocline

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“…These observations were followed by photospheric feature-tracking (Komm et al, 1993), Doppler (Ulrich, 1993) and helioseismic observations (Hathaway et al, 1996) of poleward surface meridional flows of 20 ms −1 . The observations provided critical guidance for modelers of the solar cycle.…”

Section: The Influence Of Meridional Flows On the Babcock-leighton Modelmentioning

confidence: 99%

“…In his flux transport model, Schrijver (2001) combined the models for collision, fragmentation and magnetoconvective coupling with differential rotation and meridional flow profiles empirically derived by Komm et al (1993) from NSO/KP magnetograms. Schrijver and Title (2001) proceeded to use this model to study the evolution of polar fields of the Sun during solar cycle 21, and also in non-solar stars including the case of a star 30 times more active than the Sun.…”

Section: Modifications To Random Walks Due To Magnetoconvective Couplingmentioning

confidence: 99%

Solar Magnetism in the Polar Regions

Petrie

2015

Living Rev. Sol. Phys.

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This review describes observations of the polar magnetic fields, models for the cyclical formation and decay of these fields, and evidence of their great influence in the solar atmosphere. The polar field distribution dominates the global structure of the corona over most of the solar cycle, supplies the bulk of the interplanetary magnetic field via the polar coronal holes, and is believed to provide the seed for the creation of the activity cycle that follows. A broad observational knowledge and theoretical understanding of the polar fields is therefore an essential step towards a global view of solar and heliospheric magnetic fields. Analyses of both high-resolution and long-term synoptic observations of the polar fields are summarized. Models of global flux transport are reviewed, from the initial phenomenological and kinematic models of Babcock and Leighton to present-day attempts to produce time-dependent maps of the surface magnetic field and to explain polar field variations, including the weakness of the cycle 23 polar fields. The relevance of the polar fields to solar physics extends far beyond the surface layers from which the magnetic field measurements usually derive. As well as discussing the polar fields' role in the interior as seed fields for new solar cycles, the review follows their influence outward to the corona and heliosphere. The global coronal magnetic structure is determined by the surface magnetic flux distribution, and is dominated on large scales by the polar fields. We discuss the observed effects of the polar fields on the coronal hole structure, and the solar wind and ejections that travel through the atmosphere. The review concludes by identifying gaps in our knowledge, and by pointing out possible future sources of improved observational information and theoretical understanding of these fields. Article RevisionsLiving Reviews supports two ways of keeping its articles up-to-date:Fast-track revision. A fast-track revision provides the author with the opportunity to add short notices of current research results, trends and developments, or important publications to the article. A fast-track revision is refereed by the responsible subject editor. If an article has undergone a fast-track revision, a summary of changes will be listed here.Major update. A major update will include substantial changes and additions and is subject to full external refereeing. It is published with a new publication number.For detailed documentation of an article's evolution, please refer to the history document of the article's online version at http://dx

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“…The parameters and form of this formula were designed to mimick the observed properties of meridional circulation, with a peak amplitude of ∼ 20 m/s at the surface (Komm, Howard, and Harvey, 1993;Latushko, 1994). The components of the viscous stress tensor appearing in the azimuthal component of the Navier-Stokes equation read…”

Section: Equationsmentioning

confidence: 99%

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Petrovay

Forgács‐Dajka

2002

Solar Physics

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Abstract. We present a model for torsional oscillations where the inhibiting effect of active region magnetic fields on turbulence locally reduces turbulent viscous torques, leading to a cycle-and latitude-dependent modulation of the differential rotation. The observed depth dependence of torsional oscillations as well as their phase relationship with the sunspot butterfly diagram are reproduced quite naturally in this model. The resulting oscillation amplitudes are significantly smaller than observed, though they depend rather sensitively on model details. Meridional circulation is found to have only a weak effect on the oscillation pattern.

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Meridional flow of small photospheric magnetic features

Cited by 255 publications

References 19 publications

Magnetic confinement of the solar tachocline

Magnetic confinement of the solar tachocline

Solar Magnetism in the Polar Regions

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