Fast Finectures Structures Associated with Type Ⅳ Radio Bursts

On December 16, 1988, a great solar radio burst of Type Ⅳappeared on the solar disk from 08^h31^m to 09^h41^mUT. With the fast sampling radio telecope(at three frequencies of 1.42, 2.84 and 4.00 GHz) at the Yunnan Observatory a long period oscillation(with a period of 12.5 min.) and a short period one of 1.2 min. are observed. At the same time, many fast fine structures(or spikes) in the plentiful solar radio bursts were are also recorded..According to the twist-oblique magnetic configuration in AR 5278, a qualitative dynamical mode of the coronal loop is proposed and it is suggested that the fast fine structures in the solar radio bursts are excited by the spurt of the relatiyistic electrons, producing the bursts of TypeⅣ, onto the lop of the magnetic arcade of the coronal loop.