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Petrovay, K.; Forgács‐Dajka, E.

doi:10.1023/a:1013833709489

Cited by 12 publications

(7 citation statements)

References 21 publications

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“…In this case, the flows converging on the activity belts tend to inhibit the transport of following polarities to the poles, resulting in a lower polar field (Jiang et al 2010b;note, however, that Švanda et al 2007 find no change in the flux transport in areas with increased flows). It is interesting to note that the torsional oscillation pattern, and thus presumably the associated meridional flow modulation pattern, was shown to be fairly well reproduced by a microquenching mechanism due to magnetic flux emerging in the active belts (Petrovay and Forgács-Dajka 2002). Alternatively, the modulation pattern may also be thermally induced (Spruit 2003) or it may result from large-scale magnetic field torques (Passos et al 2017;Ruždjak et al 2017).…”

Section: Photospheric Flow Variationsmentioning

confidence: 96%

Solar cycle prediction

Petrovay

2020

Living Rev Sol Phys

194

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A review of solar cycle prediction methods and their performance is given, including early forecasts for Cycle 25. The review focuses on those aspects of the solar cycle prediction problem that have a bearing on dynamo theory. The scope of the review is further restricted to the issue of predicting the amplitude (and optionally the epoch) of an upcoming solar maximum no later than right after the start of the given cycle. Prediction methods form three main groups. Precursor methods rely on the value of some measure of solar activity or magnetism at a specified time to predict the amplitude of the following solar maximum. The choice of a good precursor often implies considerable physical insight: indeed, it has become increasingly clear that the transition from purely empirical precursors to model-based methods is continuous. Model-based approaches can be further divided into two groups: predictions based on surface flux transport models and on consistent dynamo models. The implicit assumption of precursor methods is that each numbered solar cycle is a consistent unit in itself, while solar activity seems to consist of a series of much less tightly intercorrelated individual cycles. Extrapolation methods, in contrast, are based on the premise that the physical process giving rise to the sunspot number record is statistically homogeneous, i.e., the mathematical regularities underlying its variations are the same at any point of time, and therefore it lends itself to analysis and forecasting by time series methods. In their overall performance during the course of the last few solar cycles, precursor methods have clearly been superior to extrapolation methods. One method that has This article is a revised version of

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Section: Photospheric Flow Variationsmentioning

confidence: 96%

Solar cycle prediction

Petrovay

2020

Living Rev Sol Phys

194

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“…These last two features characterize the significance of the groups, their size and complexity. They are used to check the assumption that larger and more complex flux rope systems might influence the ambient flows more efficiently and this could be the reason of the torsional pattern (Petrovay, 2002).…”

Section: Observational Materials and Methods Of Analysingmentioning

confidence: 99%

“…Küker et al (1996) considered magnetic quenching of Reynolds stresses modifying the differential rotation profile. In the model of Petrovay and Forgács-Dajka (2002) the sunspots modify the turbulent viscosity in the convective zone which leads to the modulation of the differential rotation.…”

Section: Introductionmentioning

confidence: 99%

Correlations of magnetic features and the torsional pattern

Muraközy¹,

Ludmány²

2010

Proc. IAU

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Abstract. The striking similarity between the cyclic equatorward migration of the torsional oscillation belts and the sunspot activity latitudes inspired several attempts to seek an explanation of the torsional phenomenon in terms of interactions between flux ropes and plasma motions. The aim of the present work is to examine the spatial and temporal coincidences of the torsional waves and the emergence of sunspot magnetic fields. The locations of the shearing latitudes have been compared with the distributions of certain sunspot parameters by using sunspot data of more than two cycles. The bulges of the sunspot number and area distributions tend to be located within the 'forward' belts close to their poleward shearing borders. A possible geometry of the magnetic and velocity field interacion is proposed.

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“…Again, it is very important to study and monitor this phenomenon over time because it allows us to constrain our models of the interplay between magnetic field and convection (e.g. Petrovay & Forgács-Dajka 2002;Covas et al 2004). These observations are made possible by helioseismology by measuring the medium to high degree modes that are sensing the convection zone and near surface layers.…”

Section: The Solar Dynamo Tachocline and Torsional Oscillationsmentioning

confidence: 99%