Reconstruction of magnetic field surges to the poles from sunspot impulses

AbstractThe time-latitude diagram of the photospheric magnetic field of the Sun during 1975-2011 (Kitt Peak NSO, SOLIS NSO, SOHO MDI data) is analyzed using Gnevysvev's idea of impulsed structure of sunspot cycle and a flux transport concept. It is demonstrated that poleward migrations of magnetic trailing polarities are closely associated with the impulses of sunspot activity. We use a fitting procedure to reconstruct the sunspot impulses and poleward magnetic field surges. We compare our results for Cycle 22 model with the time-latitude diagram of the photospheric magnetic field of the Sun.

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How to make the Sun look less like the Sun and more like a star?

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317003908 ◽

2016 ◽

Vol 12 (S328) ◽

pp. 237-239

Author(s):

A. A. Vidotto

Keyword(s):

Magnetic Field ◽

Large Scale ◽

Vector Fields ◽

Radial Component ◽

Field Vector ◽

Small Scale ◽

General Context ◽

The Sun ◽

Flux Transport ◽

Large Scale Magnetic Field

AbstractSynoptic maps of the vector magnetic field have routinely been made available from stellar observations and recently have started to be obtained for the solar photospheric field. Although solar magnetic maps show a multitude of details, stellar maps are limited to imaging large-scale fields only. In spite of their lower resolution, magnetic field imaging of solar-type stars allow us to put the Sun in a much more general context. However, direct comparison between stellar and solar magnetic maps are hampered by their dramatic differences in resolution. Here, I present the results of a method to filter out the small-scale component of vector fields, in such a way that comparison between solar and stellar (large-scale) magnetic field vector maps can be directly made. This approach extends the technique widely used to decompose the radial component of the solar magnetic field to the azimuthal and meridional components as well, and is entirely consistent with the description adopted in several stellar studies. This method can also be used to confront synoptic maps synthesised in numerical simulations of dynamo and magnetic flux transport studies to those derived from stellar observations.

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A Quantitative Study of Magnetic Flux Transport on the Sun

Symposium - International Astronomical Union ◽

10.1017/s0074180900029934 ◽

1983 ◽

Vol 102 ◽

pp. 273-278 ◽

Cited By ~ 2

Author(s):

N.R. Sheeley ◽

J.P. Boris ◽

T.R. Young ◽

C.R. DeVore ◽

K.L. Harvey

Keyword(s):

Magnetic Field ◽

Magnetic Flux ◽

Quantitative Study ◽

Differential Rotation ◽

Meridional Circulation ◽

Diffusion Constant ◽

The Sun ◽

Flux Transport ◽

Field Reversal ◽

Best Fit

A computational model, based on diffusion, differential rotation, and meridional circulation, has been developed to simulate the transport of magnetic flux on the Sun. Using Kitt Peak magnetograms as input, we have determined a best-fit diffusion constant by comparing the computed and observed fields at later times. Our value of 730 ± 250 km2/s is consistent with Leighton's (1964) estimate of 770–1540 km2/s and is significantly larger than Mosher's (1977) estimate of 200–400 km2/s. This suggests that diffusion may be fast enough to account for the observed polar magnetic field reversal without requiring a significant assist from meridional currents.

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Sector Structure of the Solar Magnetic Field

Symposium - International Astronomical Union ◽

10.1017/s0074180900023202 ◽

1971 ◽

Vol 43 ◽

pp. 744-753 ◽

Cited By ~ 6

Author(s):

John M. Wilcox

Keyword(s):

Magnetic Field ◽

Large Scale ◽

Solar Magnetic Field ◽

Photospheric Magnetic Field ◽

The Other ◽

The Sun ◽

Sector Structure ◽

Sector Boundary ◽

The North

The solar sector structure consists of a boundary in the north-south direction such that on one side of the boundary the large-scale weak photospheric magnetic field is predominantly directed out of the Sun, and on the other side of the boundary this field is directed into the Sun. The region westward of a solar sector boundary tends to be unusually quiet and the region eastward of a solar sector boundary tends to be unusually active. This tendency is discussed in terms of flares, coronal enhancements, plage structure and geomagnetic response.

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A theoretical model of torsional oscillations from a flux transport dynamo model

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311015560 ◽

2010 ◽

Vol 6 (S273) ◽

pp. 366-368

Author(s):

Piyali Chatterjee ◽

Sagar Chakraborty ◽

Arnab Rai Choudhuri

Keyword(s):

Magnetic Field ◽

Theoretical Model ◽

Lorentz Force ◽

High Latitude ◽

Torsional Oscillation ◽

Sunspot Cycle ◽

Dynamo Model ◽

Flux Transport ◽

Torsional Oscillations ◽

The Magnetic Field

AbstractAssuming that the torsional oscillation is driven by the Lorentz force of the magnetic field associated with the sunspot cycle, we use a flux transport dynamo to model it and explain its initiation at a high latitude before the beginning of the sunspot cycle.

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Photospheric Magnetic Field of the Sun: Two Patterns of the Longitudinal Distribution

Solar Physics ◽

10.1007/s11207-007-9018-2 ◽

2007 ◽

Vol 245 (1) ◽

pp. 177-190 ◽

Cited By ~ 6

Author(s):

E. S. Vernova ◽

M. I. Tyasto ◽

D. G. Baranov

Keyword(s):

Magnetic Field ◽

Photospheric Magnetic Field ◽

Longitudinal Distribution ◽

The Sun

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Model of poleward magnetic field streams from sunspot butterflies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313002317 ◽

2012 ◽

Vol 8 (S294) ◽

pp. 87-92 ◽

Cited By ~ 1

Author(s):

Nadezhda V. Zolotova ◽

Dmitri I. Ponyavin

Keyword(s):

Magnetic Field ◽

Probability Density Function ◽

Probability Density ◽

Density Function ◽

Photospheric Magnetic Field ◽

Polar Field ◽

The Sun ◽

The Difference

AbstractThe poleward magnetic field streams on time-latitude diagram of the photospheric magnetic field of the Sun during 1975–2011 (Kitt Peak NSO, SOLIS NSO, SOHO MDI data) are modeled. We performed simulations in terms of probability density function and bipole orientation according to Joy's law and Hale's cycle. The difference between distributions of leading and trailing fluxes of bipolar sunspots defines the so-called surplus. Finally, magnetic field streams and polar field reversals are a result of meridional drift of a surplus to the poles.

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An Insight into the Solar Dynamo Theory

International Annals of Science ◽

10.21467/ias.3.1.27-36 ◽

2017 ◽

Vol 3 (1) ◽

pp. 27-36

Author(s):

Babu Ram Tiwari ◽

Mukul Kumar

Keyword(s):

Magnetic Field ◽

Toroidal Field ◽

Solar Dynamo ◽

Dynamo Model ◽

The Sun ◽

Poloidal Field ◽

Dynamo Theory ◽

Dynamo Action ◽

Flux Transport ◽

Alpha Omega

The Sun manifests its magnetic field in form of the solar activities, being observed on the surface of the Sun. The dynamo action is responsible for the evolution of the magnetic field in the Sun. The present article aims to present an overview of the studies have been carried on the theory and modelling of the solar dynamo. The article describes the alpha-omega dynamo model. Generally, the dynamo model involves the cyclic conversion between the poloidal field and the toroidal field. In case of alpha-omega dynamo model, the strong differential rotation generates a toroidal field near the base of the convection zone. On the other hand, the turbulent helicity leads to the generation of the poloidal field near the surface. The turbulent diffusion and the meridional circulation are considered as the two important flux transport agents in this model. The article briefly describes the theory of solar dynamo and mean field dynamo model.

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Numerical Simulations of Large-scale Solar Magnetic Fields

Australian Journal of Physics ◽

10.1071/ph850999 ◽

1985 ◽

Vol 38 (6) ◽

pp. 999 ◽

Cited By ~ 24

Author(s):

CR DeVore ◽

NR Sheeley Jr ◽

JP Boris ◽

TR Young Jr ◽

KL Harvey

Keyword(s):

Magnetic Field ◽

Magnetic Flux ◽

Large Scale ◽

Sunspot Cycle ◽

Active Regions ◽

The Sun ◽

Solar Magnetic Fields ◽

Field Patterns ◽

Large Scale Magnetic Field ◽

The Magnetic Field

We have solved numerically a transport equation which describes the evolution of the large-scale magnetic field of the Sun. Data derived from solar magnetic observations are used to initialize the computations and to account for the emergence of new magnetic flux during the sunspot cycle. Our objective is to assess the ability of the model to reproduce the observed evolution of the field patterns. We discuss recent results from simulations of individual active regions over a few solar rotations and of the magnetic field of the Sun over sunspot cycle 21.

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Reconstructing solar magnetic fields from historical observations

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732323 ◽

2018 ◽

Vol 616 ◽

pp. A134 ◽

Cited By ~ 2

Author(s):

I. O. I. Virtanen ◽

I. I. Virtanen ◽

A. A. Pevtsov ◽

K. Mursula

Keyword(s):

Magnetic Field ◽

Magnetic Flux ◽

Southern Hemisphere ◽

Northern Hemisphere ◽

Active Regions ◽

Surface Flux ◽

Magnetic Activity ◽

Maunder Minimum ◽

Photospheric Magnetic Field ◽

Sunspot Activity

Aims. Sunspot activity is often hemispherically asymmetric, and during the Maunder minimum, activity was almost completely limited to one hemisphere. In this work, we use surface flux simulation to study how magnetic activity limited only to the southern hemisphere affects the long-term evolution of the photospheric magnetic field in both hemispheres. The key question is whether sunspot activity in one hemisphere is enough to reverse the polarity of polar fields in both hemispheres. Methods. We simulated the evolution of the photospheric magnetic field from 1978 to 2016 using the observed active regions of the southern hemisphere as input. We studied the flow of magnetic flux across the equator and its subsequent motion towards the northern pole. We also tested how the simulated magnetic field is changed when the activity of the southern hemisphere is reduced. Results. We find that activity in the southern hemisphere is enough to reverse the polarity of polar fields in both hemispheres by the cross-equatorial transport of magnetic flux. About 1% of the flux emerging in the southern hemisphere is transported across the equator, but only 0.1%–0.2% reaches high latitudes to reverse and regenerate a weak polar field in the northern hemisphere. The polarity reversals in the northern hemisphere are delayed compared to the southern hemisphere, leading to a quadrupole Sun lasting for several years.

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