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 major...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%.展开更多
基金funded by the National Natural Science Foundation of China (NSFC) under Nos. 41074132, 41274193, 41474166, and 41774085the Special Fund of the Institute of Geophysics, China Earthquake Administration (Grant No. DQJB22X12)。
文摘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%.
