On the latitude drift of sunspot groups and solar rotation

Tuominen, Jaakko; Kyröläinen, Juhani

doi:10.1007/bf00146980

Cited by 24 publications

(2 citation statements)

References 4 publications

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“…The profile from direct Doppler measured by Hathaway (1996) is given by the dashed line. The profile from recurrent sunspot groups measured by Tuominen and Kyrolainen (1982) is given by the dashed-dotted line. .…”

Section: Discussionmentioning

confidence: 99%

Magnetic Flux Transport at the Solar Surface

et al. 2014

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After emerging to the solar surface, the Sun's magnetic field displays a complex and intricate evolution. The evolution of the surface field is important for several reasons. One is that the surface field, and its dynamics, sets the boundary condition for the coronal and heliospheric magnetic fields. Another is that the surface evolution gives us insight into the dynamo process. In particular, it plays an essential role in the Babcock-Leighton model of the solar dynamo. Describing this evolution is the aim of the surface flux transport model. The model starts from the emergence of magnetic bipoles. Thereafter, the model is based on the induction equation and the fact that after emergence the magnetic field is observed to evolve as if it were purely The induction equation then describes how the surface flows -differential rotation, meridional circulation, granular, supergranular flows, and active region inflows -determine the evolution of the field (now taken to be purely radial). In this paper, we review the modeling of the various processes that determine the evolution of the surface field. We restrict our attention to their role in the surface flux transport model. We also discuss the success of the model and some of the results that have been obtained using this model.

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Section: Discussionmentioning

confidence: 99%

Magnetic Flux Transport at the Solar Surface

et al. 2014

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“…Image reproduced with permission from Jiang et al (2014), copyright by Springer Fig. 2 Comparison of surface MC obtained using different techniques; the magnetic-element tracking estimate is from Komm et al (1993), local helioseismology inference at r ¼ 0:998 R from Basu and Antia (2010), sunspot-group tracking data from Tuominen and Kyrolainen (1982) and direct Doppler measurement from Hathaway (1996). While sunspots are poor estimators of MC, the other techniques are in fair agreement.…”

Section: Sunspot Trackingmentioning

confidence: 99%

Surface and interior meridional circulation in the Sun

Hanasoge

2022

Living Rev Sol Phys

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Solar meridional circulation is an axisymmetric flow system, extending from the equator to the poles ($$\sim $$ ∼ 20 m/s at the surface, $$\approx $$ ≈ 1% of the mean solar rotation rate), plunging inwards and subsequently completing the circuit in the interior through an equatorward return flow and a radially outward flow back up to the surface. This article reviews the profound role that meridional circulation plays in maintaining global dynamics and regulating large-scale solar magnetism. Because it is relatively weak in comparison to differential rotation ($$\sim $$ ∼ 300 m/s, $$\approx $$ ≈ 7% of the mean solar rotation rate) and owing to numerous systematical errors, accurate surface measurements were only first made in 1978 and initial inferences of interior meridional circulation were obtained using helioseismology two decades later. However, systematical biases have made it very challenging to reliably recover flow in the deep interior. Despite numerous advances that have served to improve the accuracy of inferences, the location of the return flow and the full extent of the circulation are still open problems. This article follows the historical developments and summarises contemporary advances that have led to modern inferences of surface and interior meridional flow.

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Solar magnetism: Observation and theory

Stix

1984

Astron Nachr

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This introductory review consists of four parts. The first is a discussion of the concentration of magnetic flux into small elements, the large electrical conductivity and the superadiabatic stratification as the main reasons for these "flux tubes", their relationship to the mean field, and the observational evidence of the latter. The second briefly repeats the approximations and merits of kinematic mean field dynamos. In the form of the am-dynamo, this theory esplains the reversals, latitude migration, dipolar parity and other properties of the mean solar field. The third part treats the question of flux loss from the convection zone through the buoyancy force, with the conclusion that the dynamo most probably has its main shear region at the bottom of the convection zone, or in a transition layer beneath it. The last part discusses further dynamic aspects of the Sun's magnetism, e.g. models of limit cycles and models with chaotic behaviour, and in particular the question of phase stability of the solar cycle.

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On the latitude drift of sunspot groups and solar rotation

Cited by 24 publications

References 4 publications

Magnetic Flux Transport at the Solar Surface

Magnetic Flux Transport at the Solar Surface

Surface and interior meridional circulation in the Sun

Solar magnetism: Observation and theory

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