A Sunspot Group Which Rapidly Emerged on April 5 in 1980

The rapidly emerging course of a bipolar sunspot group was observed on April 5, 1980. The results of the analysis of the course, are as follows:(1) Many small spots coalesced, into the larger one.(2) The growth rate of the large spot radius and the mean converging velocity :(<0.5km/sec) have a positive correlation:△S/zt△√πs=ηV where η≈2.5-5.5(3) In the emerging course, the arch filaments and the threads in the chromosphere above the sunspot group contracted in appearance.The geometric effect of a bundle of the emerging magnetic lines and the dynamic attraction of the current in the magnetic fibril of the small spots may be useful for explaining the observation.