Spörer’s law and relationship between the latitude and amplitude parameters of solar activity

Иванов, В. П.; Miletsky, E. V.

doi:10.1134/s0016793214070044

Cited by 16 publications

(11 citation statements)

References 13 publications

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“…This plot is similar to Fig. 6d of Ivanov & Miletsky (2014), except that we use the central latitude obtained from the fits for each year while they use an empirically derived model of the central latitude. This difference has no substantial impact.…”

Section: Introductionmentioning

confidence: 59%

The turbulent diffusion of toroidal magnetic flux as inferred from properties of the sunspot butterfly diagram

Cameron

Schüßler

2016

A&A

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Context. In order to match observed properties of the solar cycle, flux-transport dynamo models require the toroidal magnetic flux to be stored in a region of low magnetic diffusivity, typically located at or below the bottom of the convection zone. Aims. We infer the turbulent magnetic diffusivity affecting the toroidal field on the basis of empirical data. Methods. We considered the time evolution of mean latitude and width of the activity belts of solar cycles 12-23 and their dependence on cycle strength. We interpreted the decline phase of the cycles as a diffusion process. Results. The activity level of a given cycle begins to decline when the centers of its equatorward propagating activity belts come within their (full) width (at half maximum) from the equator. This happens earlier for stronger cycles because their activity belts are wider. From that moment on, the activity and the belt width decrease in the same manner for all cycles, independent of their maximum activity level. In terms of diffusive cancellation of opposite-polarity toroidal flux across the equator, we infer the turbulent diffusivity experienced by the toroidal field, wherever it is located, to be in the range 150-450 km 2 s −1 . Strong diffusive latitudinal spreading of the toroidal flux underneath the activity belts can be inhibited by an inflow toward the toroidal field bands in the convection zone with a magnitude of several meters per second. Conclusions. The inferred value of the turbulent magnetic diffusivity affecting the toroidal field agrees, to order of magnitude, with estimates based on mixing-length models for the solar convection zone. This is at variance with the requirement of flux-transport dynamo models. The inflows required to keep the toroidal field bands together before they approach the equator are similar to the inflows toward the activity belts observed with local helioseismology.

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Section: Introductionmentioning

confidence: 59%

The turbulent diffusion of toroidal magnetic flux as inferred from properties of the sunspot butterfly diagram

Cameron

Schüßler

2016

A&A

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“…The first is the rising phase, which obeys the Waldmeier effect (Waldmeier 1955), where stronger cycles tend to show a faster rise of activity levels during their ascending phase than weaker cycles (Lantos 2000;Cameron & Schüssler 2008). The second is that once the solar cycle begins to decline, all cycles decline in a similar way (Ivanov & Miletsky 2014;. A large scatter of the individual cycle about the means over all the cycles is also shown.…”

Section: Properties Of Solar Cycle Profilesmentioning

confidence: 91%

Predictability of the Solar Cycle Over One Cycle

Jiang

Wang

Jiao

et al. 2018

ApJ

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The prediction of the strength of future solar cycles is of interest because of its practical significance for space weather and as a test of our theoretical understanding of the solar cycle. The Babcock-Leighton mechanism allows predictions by assimilating the observed magnetic field on the surface. Since the emergence of sunspot groups has random properties, making it impossible to accurately predict the solar cycle and strongly limiting the scope of cycle predictions, we develop a scheme to investigate the predictability of the solar cycle over one cycle. When a cycle has been ongoing for more than three years, the sunspot group emergence can be predicted along with its uncertainty during the rest time of the cycle. The method for this prediction is to start by generating a set of random realizations that obey the statistical relations of the sunspot emergence. We then use a surface flux transport model to calculate the possible axial dipole moment evolutions. The correlation between the axial dipole moment at cycle minimum and the subsequent cycle strength and other empirical properties of solar cycles are used to predict the possible profiles of the subsequent cycle. We apply this scheme to predict the large-scale field evolution from 2018 to the end of cycle 25, whose maximum strength is expected to lie in the range from 93 to 155 with a probability of 95%.

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confidence: 70%

“…(Здесь и далее в качестве индекса актив-ности мы будем использовать среднемесячные значения рекалиброванного ряда чисел Вольфа S N [6] за 1749-2021 годы, сглаженные гауссовым фильтром с σ = 12 месяцев.) Как было показано в [1,3], сдвиги ∆t i можно подобрать таким образом, чтобы соответствующие части кривых почти совпали. .…”

Section: Doi: 1031725/0552-5829-2021-139-142unclassified

Two Phases of 11-Year Cycle and Parameterisation of Its Form

Иванов¹

2021

Proceedings of the 25th All-Russia Conference on Solar and Solar-Terrestrial Physics

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As it was shown in [1][2][3], the curve of the 11-year cycle of solar activity tends to a universal form at the second part of the descending phase. In that time the dynamic system that describes the cycle is simplified, which can be explained by magnetic field diffusion processes dominance in this phase. We present a parameterization of the cycle form that takes into account this feature of the cycle and described by a system of simple differential equations.

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Spörer’s law and relationship between the latitude and amplitude parameters of solar activity

Cited by 16 publications

References 13 publications

The turbulent diffusion of toroidal magnetic flux as inferred from properties of the sunspot butterfly diagram

The turbulent diffusion of toroidal magnetic flux as inferred from properties of the sunspot butterfly diagram

Predictability of the Solar Cycle Over One Cycle

Two Phases of 11-Year Cycle and Parameterisation of Its Form

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