Coronal Holes in Solar Cycles 21 to 23

Tlatov, A. G.; Tavastsherna, K. S.; Vasil’eva, V. V.

doi:10.1007/s11207-013-0387-4

Cited by 33 publications

(13 citation statements)

References 17 publications

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“…The total CH flux and magnetic-field strength in CHs associated with the positive-and negative-polarity photospheric magnetic fields is lower in cycle 23. This is probably due to a decrease in the strength of the polar magnetic field in cycle 23 (Wang, Robbrecht, and Sheeley, 2009;Tlatov, Tavastsherna, and Vasil'eva, 2014).…”

Section: Coronal Hole Parameters and The Global Magnetic Fieldmentioning

confidence: 99%

“…The catalog includes data on CH locations: latitude and longitude and CH parameters such as CH extension in latitude and longitude, area, associated photospheric magnetic-field strength (in G) and polarity, and magnetic flux. The detailed description of the method used for CH definition, CH parameter determination, and the catalog creation are described in Tlatov, Tavastsherna, and Vasil'eva (2014).…”

Section: Datamentioning

confidence: 99%

“…The study of CHs is important in view of their role in the space weather formation at the Earth's orbit and their influence on geomagnetic activity. CHs are associated with open magnetic field structures in the solar atmosphere and they are considered to be the source of high-speed solar wind (Nolte et al, 1976;Obridko, Shelting, and Livshits, 2011;Bilenko, 2005;Tlatov, Tavastsherna, and Vasil'eva, 2014). CHs are mainly located on unipolar magnetic fields with one predominant polarity (Bohlin and Sheeley, 1978;Bumba, Klvana, and Sýkora, 1995;Harvey, Sheeley, and Harvey, 1982;Timothy, Krieger, and Vaiana, 1975;Varsik, Wilson, and Li, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Coronal Hole and Solar Global Magnetic Field Evolution in 1976 – 2012

Bilenko

Tavastsherna

2016

Sol Phys

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Coronal hole spatial-temporal evolution is studied and comparison made with that of the solar global magnetic field in cycles 21 -23 (1976 -2012). The latitude-longitude distribution dynamics of coronal holes and the regularities in the global magnetic field associated with the solar polar field reversal are analyzed. Polar and non-polar coronal hole populations are considered. The investigation reveals some temporal and spatial regularities in coronal hole distributions that match well the global magnetic-field cycle evolution. The results show that the non-polar coronal hole longitudinal distribution follows all configuration changes in the global magnetic-field structure. Reorganizations of the global magnetic-field and coronal hole distributions occur simultaneously during a time interval of a few solar rotations. The cycle evolution of the non-polar coronal holes reflects the transition of the solar global magnetic field from the zonal structure to sectorial and vice versa. Two different type waves of nonpolar coronal holes are revealed from their latitudinal distribution. The first one is short poleward waves. They trace the poleward motion of the unipolar photospheric magnetic fields from approximately 35 • to the associated pole in each hemisphere and the redevelopment of a new-polarity polar CH. Although they start the poleward movement before the change of the polar magnetic field in the associated hemisphere, they reach the pole after the polar reversal. The other type of non-polar CH wave forms two sinusoidal branches associated with the positive-and negative-polarity magnetic fields. The complete period of the wave was equal to ≈268 CRs (22 years). These wave CHs arrive at high latitudes during declining phases when the new polarity polar CHs are already completely formed.

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Section: Coronal Hole Parameters and The Global Magnetic Fieldmentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coronal Hole and Solar Global Magnetic Field Evolution in 1976 – 2012

Bilenko

Tavastsherna

2016

Sol Phys

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“…Thus, even at the end of the sunspot cycle, the decay of ACs led to the formation of ECHs that are transported to the Pole, thereby increasing the latitudinal extent of PCHs. Such a regularity was empirically established earlier (e.g., Tlatov, Tavastsherna, and Vasil'eva, 2014), but the reasons were unknown.…”

Section: Solar-activity Development and Evolution Of Pchs At The End mentioning

confidence: 70%

Decay of Activity Complexes, Formation of Unipolar Magnetic Regions, and Coronal Holes in Their Causal Relation

Golubeva

Мордвинов

2016

Sol Phys

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North-south asymmetry of sunspot activity resulted in an asynchronous reversal of the Sun's polar fields in the current cycle. The asymmetry is also observed in the formation of polar coronal holes. A stable coronal hole was first formed at the South Pole, despite the later polar-field reversal there. The aim of this study is to understand processes making this situation possible. Synoptic magnetic maps from the Global Oscillation Network Group and corresponding coronal-hole maps from the Extreme ultraviolet Imaging Telescope aboard the Solar and Heliospheric Observatory and the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory are analyzed here to study a causal relationship between the decay of activity complexes, evolution of largescale magnetic fields, and formation of coronal holes. Ensembles of coronal holes associated with decaying active regions and activity complexes are presented. These ensembles take part in global rearrangements of the Sun's open magnetic flux. In particular, the south polar coronal hole was formed from an ensemble of coronal holes that originated after the decay of multiple activity complexes observed during 2014.

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“…В рамках модели гидромагнитного динамо Бэбкока-Лейтона [1, 2] магнитные поля хвостовых пятен должны определять переполюсовку Солнца, а значит, основные характеристики ОМП. Откуда следует ожидать наличие тесной связи между ОМП и магнитными образованиями.Если в минимуме солнечной активности КД концентрируются в области полюсов, то ближе к максимуму они могут появляться на средних и низких широтах [3,4], зачастую занимая значительную часть солнечного диска на протяжении многих оборотов Солнца [5]. Хотя к настоящему времени существование связи между ОМП, эволюцией и характеристиками КД сомнений не вызывает [6,7], тем не менее, остается много невыясненных вопросов.…”

unclassified

On the Relationship of Coronal Holes of Middle and Low Latitudes With the General Magnetic Field of the Sun

Akhtemov¹,

Ran²,

Tsap³

et al. 2019

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

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Based on EUV images and magnetograms obtained with Solar Dynamics Observatory the relationship between the total area of coronal holes (CH) of middle and low latitudes (|φ| < 60 ο ) and the sun's general magnetic field (GMF) for the period from 19 January to 07 December 2012 is investigated. It has been shown that CH boundaries determined with CHI-MERA (https://solarmonitor.org) and SPoCA (https://helioviewer.org) algorithms can differ significantly. The correlation coefficient between the weighted total area of CHs taking into account the magnetic field polarity and GMF lies in the range from 0.83 to 0.89. CHs can make a significant contribution to GMF since their magnetic fields with open magnetic configuration are not balanced on the solar disk.Общее магнитное поле Солнца (ОМП) является мерой разбаланса магнитных потоков. Следовательно, магнитное поле КД средних и низких широт может вносить существенный вклад в ОМП (здесь и в дальнейшем мы будем считать усредненное по диску поле B mean , и магнитное поле Солнца как звезды B star , если это не оговаривается, эквивалентными величинами). В рамках модели гидромагнитного динамо Бэбкока-Лейтона [1, 2] магнитные поля хвостовых пятен должны определять переполюсовку Солнца, а значит, основные характеристики ОМП. Откуда следует ожидать наличие тесной связи между ОМП и магнитными образованиями.Если в минимуме солнечной активности КД концентрируются в области полюсов, то ближе к максимуму они могут появляться на средних и низких широтах [3,4], зачастую занимая значительную часть солнечного диска на протяжении многих оборотов Солнца [5]. Хотя к настоящему времени существование связи между ОМП, эволюцией и характеристиками КД сомнений не вызывает [6,7], тем не менее, остается много невыясненных вопросов. Так, на основе данных Wilcox Solar Observatory (WSO) за период с 1975 по 1990 гг. были получены указания [8] в пользу существования достаточно слабой корреляции между ОМП и числами Вольфа

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Coronal Holes in Solar Cycles 21 to 23

Cited by 33 publications

References 17 publications

Coronal Hole and Solar Global Magnetic Field Evolution in 1976 – 2012

Coronal Hole and Solar Global Magnetic Field Evolution in 1976 – 2012

Decay of Activity Complexes, Formation of Unipolar Magnetic Regions, and Coronal Holes in Their Causal Relation

On the Relationship of Coronal Holes of Middle and Low Latitudes With the General Magnetic Field of the Sun

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