On the fine structure of microwave radio emission from solar activity centres

Different types of frequency spectra of thermal cyclotron microwave emission from active regions of the solar atmosphere, which have a fine structure, are discussed. The conditions in the activity centre (types of heigth distributions of the magnetic field and of the kinetic temperature) that provide formation of frequency spectra, containing a system of cyclotron lines and high-frequency cut-offs, are indicated. For each type of distributions, the frequency spectrum and the polarization have a specific behaviour allowing to make diagnostic of the activity centre on the basis of the appearance of the fine structure of solar microwave emission. Requirements to the radioastronomical equipment and aerial systems, which can provide a certain detection of fine structure as well as the diagnostics of coronal plasmas, are formulated. For investigations of fine structure, spectral and polarization measurements must be carried out in the wide frequency range and with a high resolution