Study of Asymmetric Behavior of Soft X-Ray Flares During Solar 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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Relationship of Soft X–Ray caused from Solar Flares and Solar Energetic Particles at Maximum of Solar cycle 24

10.32792/utq/utjsci/vol4/3/35 ◽

2019 ◽

pp. 175-178

Keyword(s):

Solar Cycle ◽

Solar Flares ◽

Energetic Particles ◽

Solar Energetic Particles ◽

X Ray ◽

Solar Cycle 24 ◽

Cycle 24 ◽

Relationship Of

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

Open Astronomy ◽

10.1515/astro-2019-0019 ◽

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.

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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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