Latitudinal and Solar Cycle Distribution of Extreme(≥X5) Flares During1976–2018  

作　　者：Qi Li Xi-Wen Zhang Gui-Ming Le 

机构地区：[1]Institute of Geophysics,China Earthquake Administration,Beijing 100081,China [2]Key Laboratory of Space Weather,National Satellite Meteorological Center(National Center for Space Weather),China Meteorological Administration,Beijing 100081,China [3]Innovation Center for FengYun Meteorological Satellite(FYSIC),Beijing 100081,China

出　　处：《Research in Astronomy and Astrophysics》2024年第12期61-68,共8页天文和天体物理学研究(英文版)

基　　金：funded by the National Natural Science Foundation of China (NSFC) under Nos. 41074132, 41274193, 41474166, and 41774085;the Special Fund of the Institute of Geophysics, China Earthquake Administration (Grant No. DQJB22X12)。

摘　　要：We studied the latitudinal and solar cycle distribution of extreme(≥X5) solar flares spanning 1976–2018. We found that all such flares were confined within the latitudinal range of [S30, N35]. Nonetheless, the majority of these flares during different solar cycles were confined in different latitudinal scopes. Statistical results showed that the southeast quadrant experienced the highest activity of extreme flares. 47.5% of the extreme flares occurred within the latitudes ≤15° of the two hemispheres, with 26.2%, 31.1%, and 42.6% in the latitudinal bands [5°, 10°],>20° and [11°, 20°] of both hemispheres, respectively. Significant N–S asymmetries were observed in the ascending phase of SC 21, the descending phase of SC 23, and both phases of SC 24. Other phases showed asymmetries primarily in latitudinal distribution. The proportion of extreme flares in the ascending phases of SCs21–24 was 22.2%, 33.3%, 38.9%, and 50%, respectively. Stronger flares(≥X10) were more likely to occur in the descending phase, with 39% of X5–X9 flares and 20% of(≥X10) flares occurring in the ascending phase. On average, 83.6% of extreme flares occurred within a period extending from two years prior to three years following the solar peak, according to our statistical analysis, with specific percentages for each cycle being 88.9%, 100%,61.1%, and 75%.

关 键 词：SUN flares-(Sun) sunspots-Sun X-rays-gamma-rays 

分 类 号：P182.52[天文地球—天文学]