Analysis of the Morphology of Solar Microwave Bursts

In this paper the dynamic spectra of microwave bursts,at every minute of the time interval between 0430 UT aad 0454 UT are analysed.The result is that the microwave bursts have the nonthermally power-law radiation spectra in the most of the ascending stage and in the high frequency part of the descending stage.The spectral indices are from 0.1 to 1.7 in general.The result is based upon observed data of the microwave bursts at the wavelengths of 3.2cm,8.2cm and 10.3cm and the Hα flares of the corresponding optical active regions at the Yunnan Observatory after 0420 UT on October 27 in 1982,It is suggested that the microwave bursts result from the synchrotron radiation caused by the sequent flow of the clumps of energetic electrons from the energe release region at the top of the magnetic arcade,toward the bottom of which electrons have the spiral motion,along the magnetic lines.Some phenomena,such as the phase lag of the bursts,appeared in the shorter wavelength,indistinction of the time-dependent details of the intensity of bursts,turjjovcr in the low frequency region,etc.can also-be explained by using the mol ion of the clumps of energetic electrons in the magnetic arcade.