Synoptic Solar Cycle 24 in Corona, Chromosphere, and Photosphere Seen by the Solar Dynamics Observatory

AbstractWe have studied the dynamics of the solar active region (AR) NOAA 12192 using full-disc continuum images and the vector magnetograms observed by the Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO). AR 12192 is the largest region of the solar cycle 24. It underwent a noticeable growth and produced 6 X-class, 22 M-class and 53 C-class flares during its disc passage. But the most peculiar fact of this AR is that it was associated with only one CME in spite of producing several X-class flares. In this work, we present the area evolution of this giant sunspot group during the first three rotations when it appeared as AR 12172, AR 12192 and AR 12209, respectively. We have also attempted to make a comparative study of the flare-related photospheric magnetic field and Lorentz force changes for both the eruptive and non-eruptive flares produced by AR 12192.

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Solar cycle-related variation in solar differential rotation and meridional flow in solar cycle 24

Earth Planets and Space ◽

10.1186/s40623-020-01314-y ◽

2020 ◽

Vol 72 (1) ◽

Author(s):

Shinsuke Imada ◽

Kengo Matoba ◽

Masashi Fujiyama ◽

Haruhisa Iijima

Keyword(s):

Solar Cycle ◽

Differential Rotation ◽

Feature Tracking ◽

Middle Latitude ◽

Meridional Flow ◽

Magnetic Element ◽

Solar Dynamics Observatory ◽

Solar Cycle 24 ◽

Solar Dynamics ◽

Cycle 24

AbstractWe studied temporal variation of the differential rotation and poleward meridional circulation during solar cycle 24 using the magnetic element feature tracking technique. We used line-of-sight magnetograms obtained using the helioseismic and magnetic imager aboard the Solar Dynamics Observatory from May 01, 2010 to March 26, 2020 (for almost the entire period of solar cycle 24, Carrington rotation from 2096 to 2229) and tracked the magnetic element features every 1 h. We also estimated the differential rotation and poleward meridional flow velocity profiles. The observed profiles are consistent with those of previous studies on different cycles. Typical properties resulting from torsional oscillations can also be observed from solar cycle 24. The amplitude of the variation was approximately ±10 m s$$^{-1}$$ - 1 . Interestingly, we found that the average meridional flow observed in solar cycle 24 is faster than that observed in solar cycle 23. In particular, during the declining phase of the cycle, the meridional flow of the middle latitude is accelerated from 10 to 17 m s$$^{-1}$$ - 1 , which is almost half of the meridional flow itself. The faster meridional flow in solar cycle 24 might be the result of the weakest cycle during the last 100 years.

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Solar Cycle Related Variation in Solar Differential Rotation and Meridional Flow in Cycle 24

10.21203/rs.3.rs-29415/v2 ◽

2020 ◽

Author(s):

Shinsuke Imada ◽

Kengo Matoba ◽

Masashi Fujiyama ◽

Haruhisa Iijima

Keyword(s):

Solar Cycle ◽

Differential Rotation ◽

Middle Latitude ◽

Meridional Flow ◽

Magnetic Element ◽

Solar Dynamics Observatory ◽

Solar Cycle 24 ◽

Solar Dynamics ◽

Cycle 24 ◽

Pm 10

Abstract We studied temporal variation of the differential rotation and poleward meridional circulation during solar cycle 24 using the magnetic element feature tracking technique. We used line-of-sight magnetograms obtained using the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory from May 01, 2010 to March 26, 2020 (for almost the entire period of solar cycle 24, Carrington Rotation from 2096 to 2229) and tracked the magnetic element features every 1 hour. We also estimated the differential rotation and poleward meridional flow velocity profiles. The observed profiles are consistent with those of previous studies on different cycles. Typical properties resulting from torsional oscillations can also be observed from solar cycle 24. The amplitude of the variation was approximately $\pm$10 m s$^{-1}$. Interestingly, we found that the average meridional flow observed in solar cycle 24 is faster than that observed in solar cycle 23. In particular, during the declining phase of the cycle, the meridional flow of the middle latitude is accelerated from 10 to 17 m s$^{-1}$, which is almost half of the meridional flow itself. The faster meridional flow in solar cycle 24 might be the result of the weakest cycle during the last 100 years.

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Solar Cycle Related Variation in Solar Differential Rotation and Meridional Flow in Cycle 24

10.21203/rs.3.rs-29415/v1 ◽

2020 ◽

Author(s):

Shinsuke Imada ◽

Kengo Matoba ◽

Masashi Fujiyama ◽

Haruhisa Iijima

Keyword(s):

Solar Cycle ◽

Differential Rotation ◽

Middle Latitude ◽

Meridional Flow ◽

Magnetic Element ◽

Solar Dynamics Observatory ◽

Solar Cycle 24 ◽

Solar Dynamics ◽

Cycle 24 ◽

Pm 10

Abstract We studied temporal variation of the differential rotation and poleward meridional circulation during solar cycle 24 using the magnetic element feature tracking technique. We used line-of-sight magnetograms obtained using the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory from May 01, 2010 to March 26, 2020 (for almost the entire period of solar cycle 24, Carrington Rotation from 2096 to 2229) and tracked the magnetic element features every 1 hour. We also estimated the differential rotation and poleward meridional flow velocity profiles. The observed profiles are consistent with those of previous studies on different cycles. Typical properties resulting from torsional oscillations can also be observed from solar cycle 24. The amplitude of the variation was approximately $\pm$10 m s$^{-1}$. Interestingly, we found that the average meridional flow observed in solar cycle 24 is faster than that observed in solar cycle 23. In particular, during the declining phase of the cycle, the meridional flow of the middle latitude is accelerated from 10 to 17 m s$^{-1}$, which is almost half of the meridional flow itself. The faster meridional flow in solar cycle 24 might be the result of the weakest cycle during the last 100 years.

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Solar Cycle Related Variation in Solar Diﬀerential Rotation and Meridional Flow in Solar Cycle 24

10.21203/rs.3.rs-29415/v3 ◽

2020 ◽

Author(s):

Shinsuke Imada ◽

Kengo Matoba ◽

Masashi Fujiyama ◽

Haruhisa Iijima

Keyword(s):

Solar Cycle ◽

Differential Rotation ◽

Feature Tracking ◽

Middle Latitude ◽

Meridional Flow ◽

Magnetic Element ◽

Solar Dynamics Observatory ◽

Solar Cycle 24 ◽

Solar Dynamics ◽

Cycle 24

Abstract We studied temporal variation of the diﬀerential rotation and poleward meridional circulation during solar cycle 24 using the magnetic element feature tracking technique. We used line-of-sight magnetograms obtained using the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory from May 01, 2010 to March 26, 2020 (for almost the entire period of solar cycle 24, Carrington Rotation from 2096 to 2229) and tracked the magnetic element features every 1 hour. We also estimated the diﬀerential rotation and poleward meridional flow velocity profiles. The observed profiles are consistent with those of previous studies on diﬀerent cycles. Typical properties resulting from torsional oscillations can also be observed from solar cycle 24. The amplitude of the variation was approximately ±10 m s−1. Interestingly, we found that the average meridional flow observed in solar cycle 24 is faster than that observed in solar cycle 23. In particular, during the declining phase of the cycle, the meridional flow of the middle latitude is accelerated from 10 to 17 m s−1, which is almost half of the meridional flow itself. The faster meridional flow in solar cycle 24 might be the result of the weakest cycle during the last 100 years.

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Characteristics of Sunquake Events Observed in Solar Cycle 24

10.5194/egusphere-egu21-1461 ◽

2021 ◽

Author(s):

Alexander Kosovichev ◽

Ivan Sharykin

Keyword(s):

Solar Cycle ◽

Solar Flares ◽

Active Regions ◽

Impulsive Phase ◽

High Energy ◽

Lower Atmosphere ◽

Solar Dynamics Observatory ◽

X Ray ◽

Solar Cycle 24 ◽

Cycle 24

<p>Helioseismic response to solar flares ("sunquakes") occurs due to localized force or/and momentum impacts observed during the flare impulsive phase in the lower atmosphere. Such impacts may be caused by precipitation of high-energy particles, downward shocks, or magnetic Lorentz force. Understanding the mechanism of sunquakes is a key problem of the flare energy release and transport. Our statistical analysis of M-X class flares observed by the Solar Dynamics Observatory during Solar Cycle 24 has shown that contrary to expectations, many relatively weak M-class flares produced strong sunquakes, while for some powerful X-class flares, helioseismic waves were not observed or were weak. The analysis also revealed that there were active regions characterized by the most efficient generation of sunquakes during the solar cycle. We found that the sunquake power correlates with maximal values of the X-ray flux derivative better than with the X-ray class. The sunquake data challenge the current theories of solar flares.</p>

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Low frequency radio observations of the ‘background’ corona during the declining phase of solar cycle 24

2019 URSI Asia-Pacific Radio Science Conference (AP-RASC) ◽

10.23919/ursiap-rasc.2019.8738381 ◽

2019 ◽

Author(s):

M. Vrunda ◽

R. Ramesh ◽

C. Kathiravan ◽

M. Rajesh

Keyword(s):

Solar Cycle ◽

Low Frequency ◽

Radio Observations ◽

Solar Cycle 24 ◽

Cycle 24

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Regression Analysis of Sunspot Numbers for the Solar Cycle 24 in Comparison to Previous Three Cycles

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v4i2.2030 ◽

2014 ◽

Vol 4 (2) ◽

pp. 477-483

Author(s):

Debojyoti Halder

Keyword(s):

Regression Analysis ◽

Solar Cycle ◽

Sunspot Number ◽

The Sun ◽

Sunspot Numbers ◽

Solar Cycle 24 ◽

Current Cycle ◽

Cycle 24

Sunspots are temporary phenomena on the photosphere of the Sun which appear visibly as dark spots compared to surrounding regions. Sunspot populations usually rise fast but fall more slowly when observed for any particular solar cycle. The sunspot numbers for the current cycle 24 and the previous three cycles have been plotted for duration of first four years for each of them. It appears that the value of peak sunspot number for solar cycle 24 is smaller than the three preceding cycles. When regression analysis is made it exhibits a trend of slow rising phase of the cycle 24 compared to previous three cycles. Our analysis further shows that cycle 24 is approaching to a longer-period but with smaller occurrences of sunspot number.

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