The 77 day periodicity in the flare rate of cycle 22
The 77 day periodicity in the flare rate of cycle 22
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DOI：
10.1086/186332
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发表时间：
1992-04
期刊：
影响因子：
--
通讯作者：
T. Bai
中科院分区：
文献类型：
--
作者：
T. Bai
分析了第22太阳活动周大耀斑的发生时刻，以探测其周期性。结果表明，从1988年11月到1990年2月，在15米的时间间隔内，有6个周期存在77天的周期。在1990年余下的时间里，看不出周期性;然而，似乎在1991年恢复了77天的周期性。这个77 d的周期被解释为大约25.5 d的基本周期的第三次谐波。在这种解释中，154-d周期是第六次谐波。同时还发现，当77-d周期或154-d周期运行时，大耀斑的发生率远高于由相对黑子数估计的发生率。
The ocurrence times of major flares of solar cycle 22 are analyzed to detect periodicities. It is found that a periodicity of 77 d was in operation in the 15-m interval from 1988 November to 1990 February for six cycles. During the rest of 1990 no periodicity was discernible; however, it seems that the 77-d periodicity resumed in 1991. This 77-d period is interpreted as the third subharmonic of the fundamental period of about 25.5 d. In this interpretation, the 154-d periodicity is the sixth subharmonic. It is also found that when the 77-d periodicity or the 154-d periodicity is in operation the occurrence rate of major flares is much higher than is expected form the relative sunspot number.