Periodic Variation of the North-South Asymmetry of Solar Activity Phenomena

2000 ◽  
Vol 179 ◽  
pp. 173-176
Author(s):  
V. K. Verma
Keyword(s):  
Solar Activity ◽  
Periodic Variation ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
Sunspot Data ◽  
Flare Index ◽  
North And South ◽  
South Asymmetry

AbstractWe report here a study of various solar activity phenomena occurring in both north and south hemispheres of the Sun during solar cycles 8–23. In the study we have used sunspot data for the period 1832–1976, flare index data for the period 1936–1993, Hα flare data 1993–1998 and solar active prominences data for the period 1957–1998. Earlier Verma reported long-term cyclic period in N-S asymmetry and also that the N-S asymmetry of solar activity phenomena during solar cycles 21, 22, 23 and 24 will be south dominated and the N-S asymmetry will shift to north hemisphere in solar cycle 25. The present study shows that the N-S asymmetry during solar cycles 22 and 23 are southern dominated as suggested by Verma.

scholarly journals Complexes of activity on the Sun in solar cycle 21

2021 ◽  
pp. 3-9
Author(s):  
Sergey Yazev ◽  
Maria Ulianova ◽  
Elena Isaeva
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Natural Environment ◽  
Statistical Data ◽  
Sunspot Activity ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
South Asymmetry

The paper provides statistical data on solar activity complexes (ACs) observed in solar cycle 21. From the synoptic charts for the 1976–1986 sunspot activity, we have detected the regions where the sunspot generation was observed at least through three Carrington Rotations (CRs). These regions were identified as AC cores. We have compiled an AC catalogue. ACs are shown to evolve quasi-periodically, in pulses that are 15–20 rotations long. We have analyzed the North-South asymmetry in the AC location. In cycle 21, 90 % of the proton flares that affected the natural environment are shown to have occurred in ACs. We note a tendency for AC activity to decrease, as well as the manifestation of the Gnevyshev—Ohl rule in AC properties, in solar cycles 21–24.

scholarly journals Complexes of activity on the Sun in solar cycle 21

2021 ◽  
Vol 7 (4) ◽  
pp. 3-9
Author(s):  
Sergey Yazev ◽  
Maria Ulianova ◽  
Elena Isaeva
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Natural Environment ◽  
Statistical Data ◽  
Sunspot Activity ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
South Asymmetry

The paper provides statistical data on solar activity complexes (ACs) observed in solar cycle 21. From the synoptic charts for the 1976–1986 sunspot activity, we have detected the regions where the sunspot generation was observed at least through three Carrington Rotations (CRs). These regions were identified as AC cores. We have compiled an AC catalogue. ACs are shown to evolve quasi-periodically, in pulses that are 15–20 rotations long. We have analyzed the North-South asymmetry in the AC location. In cycle 21, 90 % of the proton flares that affected the natural environment are shown to have occurred in ACs. We note a tendency for AC activity to decrease, as well as the manifestation of the Gnevyshev—Ohl rule in AC properties, in solar cycles 21–24.

scholarly journals Long-term changes in the North–South asymmetry of solar activity: a nonlinear dynamics characterization using visibility graphs

2014 ◽  
Vol 1 (1) ◽  
pp. 665-703 ◽  
Author(s):  
Y. Zou ◽  
R. V. Donner ◽  
N. Marwan ◽  
M. Small ◽  
J. Kurths
Keyword(s):  
Solar Activity ◽  
Complex Dynamics ◽  
The North ◽  
Visibility Graphs ◽  
Graph Properties ◽  
Dynamical Properties ◽  
Future Work ◽  
South Asymmetry ◽  
Phase Differences

Abstract. Solar activity is characterized by complex dynamics superimposed to an almost periodic, about 11 years cycle. One of its main features is the presence of a marked, time-varying hemispheric asymmetry, the deeper reasons of which have not yet been completely uncovered. Traditionally, this asymmetry has been studied by considering amplitude and phase differences. Here, we use visibility graphs, a novel tool of nonlinear time series analysis, to obtain complementary information on hemispheric asymmetries in dynamical properties. Our analysis provides deep insights into the potentials and limitations of this method, revealing a complex interplay between factors relating to statistical and dynamical properties, i.e., effects due to the probability distribution and the regularity of observed fluctuations. We demonstrate that temporal changes in the hemispheric predominance of the graph properties lag those directly associated with the total hemispheric sunspot areas. Our findings open a new dynamical perspective on studying the North–South sunspot asymmetry, which is to be further explored in future work.

scholarly journals Coronal mass ejections as a new indicator of the active Sun

2018 ◽  
Vol 13 (S340) ◽  
pp. 95-100
Author(s):  
Nat Gopalswamy
Keyword(s):  
Solar Activity ◽  
Coronal Mass Ejections ◽  
Rotation Period ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
Transient Events ◽  
Key Indicators ◽  
Quiescent Filament ◽  
Activity Indices

AbstractCoronal mass ejections (CMEs) have become one of the key indicators of solar activity, especially in terms of the consequences of the transient events in the heliosphere. Although CMEs are closely related to the sunspot number (SSN), they are also related to other closed magnetic regions on the Sun such as quiescent filament regions. This makes CMEs a better indicator of solar activity. While sunspots mainly represent the toroidal component of solar magnetism, quiescent filaments (and hence CMEs associated with them) connect the toroidal and poloidal components via the rush-to-the-pole (RTTP) phenomenon. Taking the end of RTTP in each hemisphere as an indicator of solar polarity reversal, it is shown that the north-south reversal asymmetry has a quasi-periodicity of 3-5 solar cycles. Focusing on the geospace consequences of CMEs, it is shown that the maximum CME speeds averaged over Carrington rotation period show good correlation with geomagnetic activity indices such as Dst and aa.

scholarly journals Long-term changes in the north–south asymmetry of solar activity: a nonlinear dynamics characterization using visibility graphs

2014 ◽  
Vol 21 (6) ◽  
pp. 1113-1126 ◽  
Author(s):  
Y. Zou ◽  
R. V. Donner ◽  
N. Marwan ◽  
M. Small ◽  
J. Kurths
Keyword(s):  
Solar Activity ◽  
Complex Dynamics ◽  
The North ◽  
Visibility Graphs ◽  
Graph Properties ◽  
Dynamical Properties ◽  
Future Work ◽  
South Asymmetry ◽  
Phase Differences

Abstract. Solar activity is characterized by complex dynamics superimposed onto an almost periodic, approximately 11-year cycle. One of its main features is the presence of a marked, time-varying hemispheric asymmetry, the deeper reasons for which have not yet been completely uncovered. Traditionally, this asymmetry has been studied by considering amplitude and phase differences. Here, we use visibility graphs, a novel tool of nonlinear time series analysis, to obtain complementary information on hemispheric asymmetries in dynamical properties. Our analysis provides deep insights into the potential and limitations of this method, revealing a complex interplay between factors relating to statistical and dynamical properties, i.e., effects due to the probability distribution and the regularity of observed fluctuations. We demonstrate that temporal changes in the hemispheric predominance of the graph properties lag those directly associated with the total hemispheric sunspot areas. Our findings open a new dynamical perspective on studying the north–south sunspot asymmetry, which is to be further explored in future work.

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

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