Essential features of long-term changes of areas and diameters of sunspot groups in solar activity cycles 12–24

Efimenko, V. M.; Lozitsky, V. G.

doi:10.1016/j.asr.2018.03.012

Cited by 12 publications

(9 citation statements)

References 20 publications

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“…After the discovery of the magnetic nature of the spots, it was established that the spatio-temporal pattern of the magnetic polarity of groups of sunspots is restored after 22 years in average [2], thus determining the magnetic cycle of the Sun, which was called the Hale cycle. Recently, as a result of studying the distributions of the number of groups of sunspots according to their equivalent diameters, the evidence of a double Hale cycle (about 44 years) was found [3]. As was correctly noted in [3], it seems that the 22-year Hale cycle and the 44-year cycle of the distribution of diameters of sunspot groups constitute a physically unified formation.…”

Section: Introductionmentioning

confidence: 75%

“…Recently, as a result of studying the distributions of the number of groups of sunspots according to their equivalent diameters, the evidence of a double Hale cycle (about 44 years) was found [3]. As was correctly noted in [3], it seems that the 22-year Hale cycle and the 44-year cycle of the distribution of diameters of sunspot groups constitute a physically unified formation.…”

Section: Introductionmentioning

confidence: 75%

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Kinematic Dynamo Model of a Solar Magnetic Cycle

et al. 2023

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The paper deals with the problem of explaining the origin and nature of the space-time variations in the magnetic activity of the Sun. It presents a new hydrodynamic model of the solar magnetic cycle, which uses helioseismological data on the differential rotation of the solar convective zone. The model is based on the hypothesis of the emergence of global flows as a result of the loss of stability of a differentially rotating plasma layer in the convective zone. First, the hydrodynamic global plasma flows are calculated without accounting for the effect of a magnetic field on them. Under this condition, it is shown that the solutions found describe all global flows observed on the surface of the Sun: permanent meridional circulation from the equator to the poles, torsional oscillations and space-time variations of the meridional flow. We conclude that the last two flows are azimuthal and meridional components of a single three-dimensional global hydrodynamic flow. Second, to simulate the dynamics of the magnetic field, the found velocities of global migrating flows and the spatial profile of the angular velocity of the internal differential rotation of the solar convective zone obtained from helioseismic measurements were used. Good coincidences have been obtained between the characteristics of the calculated dynamics of global migrating flows and the variable global magnetic fields generated by them with the observed values on the solar surface. An explanation is given for some phenomena on the surface of the Sun, which could not be explained within the framework of the available models.

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Section: Introductionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 75%

Kinematic Dynamo Model of a Solar Magnetic Cycle

et al. 2023

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“…This effect was interpreted as a manifestation of a double Hale cycle. The analysis of the large sunspot group diameters (Efimenko and Lozitsky, 2018) also shows the 44-year period in the variations of solar activity. There are some indications that the 44-year periodicity of solar activity is reflected in cosmic ray intensity.…”

Section: Maximum and Integral Of The Longitudinal Asymmetrymentioning

confidence: 99%

Longitudinal Asymmetry of Solar Activity and the Gnevyshev-Ohl Rule

Vernova¹,

Izmiran²,

Tyasto³

et al. 2019

Proceedings of the 23rd All-Russia Conference on Solar and Solar-Terrestrial Physics

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The vector representation of sunspots is used to study the nonaxisymmetric features of the solar activity distribution (sunspot data from Greenwich-USAF/NOAA, 1874-2016.The vector of the longitudinal asymmetry is defined for each Carrington rotation; its modulus characterizes the magnitude of the asymmetry, while its phase points to the active longitude. These characteristics are to a large extent free from the influence of a stochastic component and emphasize the deviations from the axisymmetry. For the sunspot area, the modulus of the vector of the longitudinal asymmetry changes with the 11-year period; however, in contrast to the solar activity, the amplitudes of the asymmetry cycles obey a special scheme. Each pair of cycles from 12 to 23 follows in turn the Gnevyshev-Ohl rule (an even solar cycle is lower than the following odd cycle) or the "anti-Gnevyshev-Ohl rule" (an odd solar cycle is lower than the preceding even cycle). This effect is observed in the longitudinal asymmetry of the whole disk and the southern hemisphere. Possibly, this effect is a manifestation of the 44-year structure in the activity of the Sun. Northern hemisphere follows the Gnevyshev-Ohl rule in Solar Cycles 12-17, while in Cycles 18-23 the anti-rule is observed. Phase of the longitudinal asymmetry vector points to the dominating (active) longitude. Distribution of the phase over the longitude was studied for two periods of the solar cycle, ascent-maximum and descent-minimum, separately. The longitudinal distribution displays maximum at the longitude ∼ 180 • during ascent-maximum and at ∼ 0 • /360 • during descent-minimum. The active longitude changes with the reversals of polarity of the local (minimum of solar activity) and global magnetic fields (reversal of polar magnetic field).

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“…Останнiми роками з'явилася низка праць, присвячених тонкiй структурi 11-лiтнього циклу сонячної активностi, а саме дослiдженню iснування на Сонцi двох популяцiй плям (роботи Наговiцина, Пєвцова та iн.) [1][2][3][4][5][6], що вiдрiзняються за властивостями; припускають, що вони можуть формуватися в рiзних частинах конвективної зони. Як параметри роздiлення груп плям на двi популяцiї велику i дрiбну використовують: а) тривалiсть життя груп плям [3], б) їхнi розмiри [4], в) розподiл магнiтного потоку [5].…”

Section: вступunclassified

“…Як параметри роздiлення груп плям на двi популяцiї велику i дрiбну використовують: а) тривалiсть життя груп плям [3], б) їхнi розмiри [4], в) розподiл магнiтного потоку [5]. Привертає до себе увагу робота Єфiменка, Лозицького [6], у якiй виявлено нетипово великi розмiри площ груп плям у 18-му циклi сонячної активностi (за останнi 140 рокiв згiдно з базою даних Ґрiнвiча).…”

Section: вступunclassified