Pulsations of solar radio emission as a diagnostic tool for coronal plasma parameters

A.V.Stepanov

The review is focused mainly on the origin of quasi-periodical pulsations in solar flare microwave emission and on the diagnostics of coronal plasma. The modulation of radioemission is due to the variations in the parameters of a coronal magnetic loop. Two models for coronal loop oscillations are considered: (1) MHD eigen-mode oscillations, and (2) flare loop as an equivalent RLC-circuit. Therewith radial and ballooning oscillations of a magnetic loop were paid main attention in the approach (1). The model (1) is applied as a diagnostic tool for magnetic field, electron number density, plasma temperature, and spectral index of energetic electrons in flare coronal loops. RLC-circuit approach (2) gives us the electric current value in a flare loop, and energy stored in a loop. Observational evidence for energy accumulation and dissipation in a flare is presented using Metsahovi data. The origin of radio pulsations from red dwarf AD Leo is also discussed.