Microwave Diagnostics of Dynamic Processes and Oscillations in Groups of Solar Coronal Magnetic Loops

Low-frequency (LF) modulations of the solar microwave radiation (37 GHz) recorded at the Metsähovi Radio Observatory, are analyzed. Since the intensity of solar microwave radiation, produced by the electron gyrosynchrotron mechanism, is dependent on a value of the background magnetic field [Dulk, G. A.: 1985, Ann. Rev. Astron. Astrophys. 23, 169–224], slow variations of the magnetic field associated with disturbances of the electric current in a radiating source, can modulate the intensity of the microwave radiation. The observed multi-track features of the LF spectra are interpreted as a signature of a complex multi-loop structure of the radiating source. Application of the equivalent electric circuit models of interacting loops allows to explain and reproduce the main dynamical features of the observed LF modulation dynamic spectra.