Temporal Evolution of the Rotation of the Interplanetary Magnetic Field Bx, By, and Bz Components

Xiang, N. B.; Ning, Zongjun; Li, F. Y.

doi:10.3847/1538-4357/ab91bc

Cited by 8 publications

(3 citation statements)

References 95 publications

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“…To conclude, the study affirms that periodic variations in the solar rotational period (∼27 d) in the northern and southern hemispheres of the Sun demonstrate a kind of asymmetrical behavior. The value of synodic solar rotation is very consistent with the result in Xiang et al (2020) and references therein. The rotational nature of the northern and southern hemispheres is relevant, and it is interconnected with the solar dynamo and magnetic field generation.…”

Section: Discussionsupporting

confidence: 91%

Signature of the 27-day variation in hemispheric sunspot activity and asymmetry during 2010–2015

Singh

Farid

Pant

et al. 2021

Res. Astron. Astrophys.

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In the present work, we study the time evolution, significance of the N-S asymmetry excesses presented as a function of the solar cycle and prominent rotational periods (∼27 d) separately for the northern and southern hemispheres. We have investigated short-term variations of the hemispheric solar activity (sunspot numbers and sunspot areas) during the time period 2010–2015, which covers the ascending and the maximum phase of solar cycle 24. We have implemented the Lomb-Scargle periodogram and continuous wavelet transform power spectrum techniques to study the time evolution and dominant rotational periods separately for the northern and southern hemispheres, and whole solar disk. Our results showed that the northern hemisphere exhibited longer solar synodic periods than the southern hemisphere, indicating that the northern hemisphere has a lower rotation rate. Moreover, the northern hemisphere was found to be dominant before transferring to the southern hemisphere during mid-2013. Also, the sunspot areas clearly demonstrated a two-peak structure of solar activity in the northern and southern hemispheres respectively during 2012 and 2014. The statistical significance of the southern hemisphere affirmed enhanced excess during the maximum phase of solar cycle 24.

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Section: Discussionsupporting

confidence: 91%

Signature of the 27-day variation in hemispheric sunspot activity and asymmetry during 2010–2015

Singh

Farid

Pant

et al. 2021

Res. Astron. Astrophys.

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“…Variations of the chromospheric rotation in solar cycles are rarely mentioned. The main reasons for the relatively less well-determined chromospheric rotation are as follows: (i) some types of long-lived tracers are less prominent in the chromosphere, and (ii) long-lived tracers are not easy to distinguish in long-term observations of the chromosphere (Xiang et al 2020;Xu et al 2020). Long ago, Antonucci et al (1979aAntonucci et al ( , 1979b investigated the effect of the lifetime and size of feature tracers on the chromospheric rotation.…”

Section: Introductionmentioning

confidence: 99%

Solar-cycle-related Variation of Differential Rotation of the Chromosphere

Wan

Gao

2022

ApJ

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Solar-cycle-related variation of the solar chromospheric rotation is studied by analyzing the chromospheric rotation rate of 938 synoptic maps generated from the Ca ii K line at the Mount Wilson Observatory during the period of 1915 August 10 to 1985 July 7. The results obtained are as follows: (1) The parameters A (the equatorial rotation rate) and B (the latitudinal gradient of rotation) in the standard form of differential rotation both show a decreasing trend in the considered time frame, although A has weak statistical significance. (2) There is a significant negative correlation between the level of solar activity and parameter B, indicating that there seems to be a correlation between field strength and chromospheric differential rotation. (3) During solar cycles 15, 16, 19, 20, and 21, the southern hemisphere rotates faster, whereas in cycles 17 and 18, the northern hemisphere rotates faster. (4) There exists a significant negative correlation between the N–S asymmetry of the chromospheric rotation rate and that of solar activity, indicating that differential rotation of the chromosphere seems to be strengthened by stronger magnetic activity in a certain hemisphere. Possible explanations for the above results are given.

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“…Further, we have explored the evolutions of Rieger type of periods in different cycles under study with wavelet technique. Previously, the above mentioned periods and their solar cycle variations were reported in different solar and helioseismic indices (Oliver, Carbonell, and Ballester, 1992;Krivova and Solanki, 2002;Chowdhury, Jain, and Awasthi, 2013;Vecchio et al, 2012;Broomhall and Nakariakov, 2015;Kiss and Erdélyi, 2018;Kilcik et al, 2020;Xiang, Ning, and Li, 2020;Zhang et al, 2022;Korsós et al, 2023, and references therein).…”

Section: Discussionmentioning

confidence: 94%

Temporal and Periodic Analysis of Penumbra-Umbra Ratio for the Last Four Solar Cycles

Chowdhury

Kılçık

Saha

et al. 2023

Preprint

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We investigate the long-term dynamic behavior of the sunspot penum8bra to umbra area ratio by analyzing the Debrecen Photoheliographic Data9 (DPD) of sunspot groups during the period 1976–2017 (Solar Cycles 21-24). We consider all types of spots and notice that the average penumbra-umbra ratio does not exhibit any significant variation with spot latitudes, solar cycle phases as well as sunspot cycle strengths. However, the behavior of this ratio is different when we consider the latitudinal distribution of the northern and southern hemisphere separately. Our analysis indicates that the average spot ratio varies from 5.5 to 6.5 and for very large sunspots (> 5000 μhem; one μhem is 10-6 the area of millionth of visual solar hemisphere) its value rises to about 8.3. Further, we found that this ratio exhibit some kind of solar cycle trend for both smaller (area <100 μhem) and large (area > 100 μhem) sunspots. Finally, we have studied the periodic and quasi-periodic variations present in this ratio time series by the multitaper method (MTM) and wavelet technique. We found that along with the ∼11-years (solar cycle period), the penumbra to umbra area ratio data also show several mid-term variations, specifically, Rieger type and quasi-biennial periodicities.We also found that the Rieger-type of periods occurs in all cycles, but the temporal evolution and the modulation of these types of periodicities are different in different solar cycles.

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Temporal Evolution of the Rotation of the Interplanetary Magnetic Field B_x, B_y, and B_z Components

Cited by 8 publications

References 95 publications

Signature of the 27-day variation in hemispheric sunspot activity and asymmetry during 2010–2015

Signature of the 27-day variation in hemispheric sunspot activity and asymmetry during 2010–2015

Solar-cycle-related Variation of Differential Rotation of the Chromosphere

Temporal and Periodic Analysis of Penumbra-Umbra Ratio for the Last Four Solar Cycles

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