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• 论文 •

### THE PERIODICITY OF AR5395 EVOLUTION

Lin Hua-an, Wang Shi-jin

1. Center for Space Science and Applied Research, Academia Sinica, Beijing
• Received:1990-06-08 Revised:1900-01-01 Online:1991-08-24 Published:1991-08-24

Abstract: There are periodical characteristics in the evolution of AR5395 shown by analysing the observational data of X-ray flares and area of sunspot group. Fod AR5395 the variation of peak flux Fx of soft X-ray exhibits a periodicity about 24.3 hours, the periodicity for the occurrence rate Nx of X-ray flares is about 12.2 houds, and the area Sx of sunspot groups varies with 24.4 hours period. The phase relations among these three periodical parameters show: (1) the flares with Xclass generally appears at the decreasing phase of the peridlical variation of sunspot area; (2) the area of sunspot groups takes about 16 hours to reach the maximum in the 24.4 hours period; (3) the rate of occurrence of X-ray flares reaches the maximum before the appearance of Xclass flare about 12 hours. It seems that AR5395 is in a state of energy store-release-store cycle of large flares with a periodicity about 24 hours.