The solar magnetic field since 1700

Jiang, Jingyang; Cameron, R. H.; Schmitt, D.; Schüßler, M.

doi:10.1051/0004-6361/201016168

Cited by 52 publications

(80 citation statements)

References 48 publications

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“…Stronger cycle wings tend to start at higher latitudes and to have a greater latitudinal extent. This confirms earlier results from Jiang et al (2011), for example, that stronger cycles tend to have a greater latitudinal extent, which has been found previously for solar cycles and is now generalized for the hemispheric wings.…”

Section: Discussionsupporting

confidence: 81%

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Wings of the butterfly: Sunspot groups for 1826–2015

Leussu

Usoskin

Pavai

et al. 2017

A&A

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The spatio-temporal evolution of sunspot activity, the so-called Maunder butterfly diagram, has been continously available since 1874 using data from the Royal Greenwich Observatory, extended by SOON network data after 1976. Here we present a new extended butterfly diagram of sunspot group occurrence since 1826, using the recently digitized data from Schwabe (1826Schwabe ( -1867 and Spörer (1866Spörer ( -1880. The wings of the diagram are separated using a recently developed method based on an analysis of long gaps in sunspot group occurrence in different latitude bands. We define characteristic latitudes, corresponding to the start, end, and the largest extent of the wings (the F, L, and H latitudes). The H latitudes (30 • -45 • ) are highly significantly correlated with the strength of the wings (quantified by the total sum of the monthly numbers of sunspot groups). The F latitudes (20 • -30 • ) depict a weak tendency, especially in the southern hemisphere, to follow the wing strength. The L latitudes (2 • -10 • ) show no clear relation to the wing strength. Overall, stronger cycle wings tend to start at higher latitudes and have a greater wing extent. A strong (5-6)-cycle periodic oscillation is found in the start and end times of the wings and in the overlap and gaps between successive wings of one hemisphere. While the average wing overlap is zero in the southern hemisphere, it is two to three months in the north. A marginally significant oscillation of about ten solar cycles is found in the asymmetry of the L latitudes. The new long database of butterfly wings provides new observational constraints to solar dynamo models that discuss the spatio-temporal distribution of sunspot occurrence over the solar cycle and longer.

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Section: Discussionsupporting

confidence: 81%

“…Table 2). This implies that the latitudinal extent of the wings is quite robustly related to the strength of the corresponding hemispheric wing, as shown earlier by Jiang et al (2011) for full cycles. On the other hand, because of the great scatter of points in Fig.…”

Section: Relation To Wing Strengthsupporting

confidence: 51%

Wings of the butterfly: Sunspot groups for 1826–2015

Leussu

Usoskin

Pavai

et al. 2017

A&A

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“…If a sufficient amount of unipolar flux emerges and clusters together to form extended patches, the associated fields may be open. As a consequence, the open flux on global scales varies in the course of the solar cycle (its long-term variation was computed by Solanki et al 2000Solanki et al , 2002Jiang et al 2011). Since the interplanetary magnetic field is fed by the magnetically open regions on the Sun, a similar modulation over the course of a solar cycle was expected too.…”

Section: Cyclic Changes Of the Coronal Magnetic Fieldmentioning

confidence: 99%

The magnetic field in the solar atmosphere

Wiegelmann

Thalmann

Solanki

2014

Astron Astrophys Rev

176

125

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This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the solar chromosphere and corona as well as in accelerating the solar wind. Our main emphasis is the magnetic field in the upper solar atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher solar layers. Also, the discussion of the solar atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quiet Sun and coronal holes.

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“…Black solid curve is the evolution of axial dipole field and black dashed curve is the evolution of equatorial dipole field. They are adapted from Jiang et al(2011b) who physically reconstructed the solar total, polar and total flux since 1700 onward based on the semi-synthetic records of emerging sunspot groups (Jiang et al 2011a). We may see that the axial dipole is roughly anti-phase with Here is a summary about the physical reason for the geomagnetic (aa-index) variations.…”

Section: Physical Reasons For the Geomagnetic Variationsmentioning

confidence: 99%

Solar-cycle precursors and predictions

Jiang

2012

Proc. IAU

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Abstract. The sunspot number data during the past 400 years indicates that both the profile and the amplitude of the solar cycle have large variations. Some precursors of the solar cycle were identified aiming to predict the solar cycle. The polar field and the geomagnetic index are two precursors which are received the most attention. The geomagnetic variations during the solar minima are potentially caused by the solar polar field by the connection of the solar open flux. The robust prediction skill of the polar field indicates that the memory of the dynamo process is less than 11 yrs based on the frame of the Babcock-Leighton flux transport dynamo. One possible reason to get the short magnetic memory is the high magnetic diffusivity in the convective zone. Our recent studies show that the radial downward pumping is another possible reason. Based upon the mechanism, we well simulate the cycle irregularities during RGO time period. This opens the possibility to set up a standard dynamo based model to predict the solar cycle. In the end, the no correlation between the polar field and the preceding cycle strength due to two nonlinearities involved in the sunspot emergence will be stressed.

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The solar magnetic field since 1700

Cited by 52 publications

References 48 publications

Wings of the butterfly: Sunspot groups for 1826–2015

Wings of the butterfly: Sunspot groups for 1826–2015

The magnetic field in the solar atmosphere

Solar-cycle precursors and predictions

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