scholarly journals Statistical Study of North-South Asymmetry during Solar Cycles 21, 22, 23 and 24

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Raj Kumar ◽  
Mahesh Chandra Mathpal ◽  
Bimal Pande ◽  
Seema Pande
Keyword(s):  
Statistical Study ◽  
Flare Activity ◽  
Solar Cycles ◽  
X Ray ◽  
The North ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Class Flare ◽  
South Asymmetry ◽  
Northern And Southern Hemispheres

North-south asymmetry has been a significant aspect exhibited by various solar activity parameters of the Sun. In this work we have statistically analyzed soft X-ray (SXR) flares during the period Jan 1981 to Dec 2016 for four different solar cycles (SCs) covering cycles 21, 22, 23 and 24. We have presented the class wise (B, C, M & X) variation of SXR flares for these SCs. SXR flare activity is lowest in solar cycle 24 as compared to cycles 22 and 23. It is shown that M class activity continuously decreased from SC 21 to 24. X and C class flares show higher activity in SC 22 and 23 as compared to SC 24, whereas B class flare activity is higher for SC 23. We have also studied the north-south (N-S) asymmetry of SXR flares for SCs 21, 22, 23 and 24. Our study revealed that during SCs 21, 22 and 23 the flare activity was more pronounced in the Southern hemisphere. However, the flare activity was equally distributed between the northern and southern hemispheres for SC 24

scholarly journals Statistical Study of North-South Asymmetry during Solar Cycles 21, 22, 23 and 24

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Raj Kumar ◽  
Mahesh Chandra Mathpal ◽  
Bimal Pande ◽  
Seema Pande
Keyword(s):  
Statistical Study ◽  
Flare Activity ◽  
Solar Cycles ◽  
X Ray ◽  
The North ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Class Flare ◽  
South Asymmetry ◽  
Northern And Southern Hemispheres

North-south asymmetry has been a significant aspect exhibited by various solar activity parameters of the Sun. In this work we have statistically analyzed soft X-ray (SXR) flares during the period Jan 1981 to Dec 2016 for four different solar cycles (SCs) covering cycles 21, 22, 23 and 24. We have presented the class wise (B, C, M & X) variation of SXR flares for these SCs. SXR flare activity is lowest in solar cycle 24 as compared to cycles 22 and 23. It is shown that M class activity continuously decreased from SC 21 to 24. X and C class flares show higher activity in SC 22 and 23 as compared to SC 24, whereas B class flare activity is higher for SC 23. We have also studied the north-south (N-S) asymmetry of SXR flares for SCs 21, 22, 23 and 24. Our study revealed that during SCs 21, 22 and 23 the flare activity was more pronounced in the Southern hemisphere. However, the flare activity was equally distributed between the northern and southern hemispheres for SC 24

scholarly journals Super-active regions in solar cycle 24

2015 ◽  
Vol 11 (S320) ◽  
pp. 309-314 ◽  
Author(s):  
Anqin Chen ◽  
Jingxiu Wang
Keyword(s):  
Solar Cycle ◽  
Active Regions ◽  
Total Solar Irradiance ◽  
Flare Activity ◽  
Solar Cycles ◽  
Solar Cycle 24 ◽  
Satisfactory Account ◽  
Current Cycle ◽  
Flare Index ◽  
Cycle 24

AbstractComparing with solar cycles 21-23, the level of solar activity in the current cycle is very low. So far, there have been only five SARs and 45 X class flares. The monthly smoothed total solar irradiance decreased sharply by 0.09% from the maximum of cycle 23 to the minima between cycles 23 and 24. In this contribution, we present new studies on SARs in Cycle 24. The SARs in the current cycle have relatively smaller flare index (Iflare) and composite vector field index (Icom) comparing with the SARs in cycles 22 and 23. There is a clearly linear relationship between Iflare and Icom. The emphasis of this contribution is put on the similarity and different behaviors of vector magnetic fields of the SARs in the current solar cycle and the previous ones. We try to get a satisfactory account for the general characteristics and relatively lower level of solar flare activity in Cycle 24.

scholarly journals LOW-POWER SOLAR FLARES OF OPTICAL AND X-RAY WAVELENGTHS FOR SOLAR CYCLES 21–24

2020 ◽  
Vol 6 (3) ◽  
pp. 18-25
Author(s):  
Aleksandr Borovik ◽  
Anton Zhdanov
Keyword(s):  
Solar Activity ◽  
Low Power ◽  
Solar Flares ◽  
Optical Emission ◽  
Flare Activity ◽  
X Rays ◽  
Solar Cycles ◽  
X Ray ◽  
Cycle 24 ◽  
Using Data

Using data obtained in optical and X-ray wavelengths, we have analyzed solar flare activity for cycles 21–24. Over the last three cycles, solar activity is shown to decrease significantly. As compared to solar cycle 21 (the most active over the last 50 years), in cycle 24 2–4-class large optical flares are 4.4 times rarer; 1-class flares, 8.2 times; and S-class small flares, 4.1 times. The number of X-class flares decreased 3.7 times; M-class flares, 3.2 times. This confirms that secular solar activity trends affect peak values of 11-year cycles. It is shown that optical low-power flares can be accompanied by proton fluxes and X-ray bursts of different intensity, including X-class ones. Ranges of small flare emission in soft X-rays largely overlap with emission ranges of flares of high optical classes. We have confirmed that X-ray emission from solar flares appears on average 2 min before the optical emission. The X-ray maximum for small optical flares and 1-class flares occurs approximately 1 min later; for 2–4-class flares, 2 min.

scholarly journals North-South Distribution and Asymmetry of GOES SXR Flares during Solar Cycle 24

2020 ◽  
Vol 28 (1) ◽  
pp. 228-235
Author(s):  
Anita Joshi ◽  
Ramesh Chandra
Keyword(s):  
Data Analysis ◽  
Solar Cycle ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Solar Maximum ◽  
X Ray ◽  
The North ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Second Peak

AbstractHere we present the results of the study of the north-south (N-S) distribution and asymmetry of GOES soft X-ray (SXR) flares during solar cycle 24. The period of study includes ascending, maximum and descending phases of the cycle. During the cycle double-peaked (2011, 2014) solar maximum has occurred. The cycle peak in the year 2011 is due to B-class flares excess activity in the northern hemisphere (NH) whereas C and M class flares excess activity in the southern hemisphere (SH) supported the second peak of the cycle in 2014. The data analysis shows that the SXR flares are more pronounced in 11 to 20 degree latitudes for each hemisphere. Cumulative values of SXR flare count show northern excess during the ascending phase of the cycle. However, in the descending phase of the cycle, southern excess occurred. In the cycle a significant SH dominated asymmetry exists. Near the maximum of the cycle, the asymmetry enhances pronouncedly and reverses in sign.

scholarly journals LOW-POWER SOLAR FLARES OF OPTICAL AND X-RAY WAVELENGTHS FOR SOLAR CYCLES 21–24

2020 ◽  
Vol 6 (3) ◽  
pp. 16-22
Author(s):  
Aleksandr Borovik ◽  
Anton Zhdanov
Keyword(s):  
Solar Activity ◽  
Low Power ◽  
Solar Flares ◽  
Optical Emission ◽  
Flare Activity ◽  
X Rays ◽  
Solar Cycles ◽  
X Ray ◽  
Cycle 24 ◽  
Using Data

Using data obtained in optical and X-ray wavelengths, we have analyzed solar flare activity for cycles 21–24. Over the last three cycles, solar activity is shown to decrease significantly. As compared to solar cycle 21 (the most active over the last 50 years), in cycle 24 2–4-class large optical flares are 4.4 times rarer; 1-class flares, 8.2 times; and S-class small flares, 4.1 times. The number of X-class flares decreased 3.7 times; M-class flares, 3.2 times. This confirms that secular solar activity trends affect peak values of 11-year cycles. It is shown that optical low-power flares can be accompanied by proton fluxes and X-ray bursts of different intensity, including X-class ones. Ranges of small flare emission in soft X-rays largely overlap with emission ranges of flares of high optical classes. We have confirmed that X-ray emission from solar flares appears on average 2 min before the optical emission. The X-ray maximum for small optical flares and 1-class flares occurs approximately 1 min later; for 2–4-class flares, 2 min.

X-Ray Flares and Activity Complexes on the Sun in Solar Cycle 24

2020 ◽  
Vol 64 (1) ◽  
pp. 58-65 ◽  
Author(s):  
E. S. Isaeva ◽  
V. M. Tomozov ◽  
S. A. Yazev
Keyword(s):  
Solar Cycle ◽  
The Sun ◽  
X Ray ◽  
Solar Cycle 24 ◽  
Cycle 24

scholarly journals North-south asynchrony and long-term variations of sunspot latitudes

2008 ◽  
Vol 4 (S259) ◽  
pp. 237-238 ◽  
Author(s):  
Nadezhda V. Zolotova ◽  
D. I. Ponyavin
Keyword(s):  
Sunspot Area ◽  
Magnetic Equator ◽  
Phase Component ◽  
Long Period ◽  
The North ◽  
Sign Change ◽  
The Mean ◽  
South Asymmetry ◽  
Northern And Southern Hemispheres

AbstractThe long-term records of sunspot area available separately for Northern and Southern Hemispheres have been investigated by means of cross-recurrence technique. Phase component of the north-south asymmetry was extracted. This measure demonstrates long-period systematic variations with the sign change of hemispheric leading in 1930s and 1960s. Moreover phase north-south asynchrony anticorrelates with the so called magnetic equator, which was defined as difference of the mean sunspot latitudes between two hemispheres. Relationships of the phase north-south asynchrony, magnetic equator and butterfly diagrams are presented and discussed.

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