Low frequency observations of transient quasi-periodic radio emission from the solar atmosphere

We report low frequency observations of the quasi-periodic, circularly polarized, harmonic type III radio bursts whose associated sunspot active regions were located close to the solar limb. The measured periodicity of the bursts at 80 MHz was $approx$ 5.2 s and their average degree of circular polarization ($dcp$) was $approx 0.12$. We calculated the associated magnetic field $B$ : (1) using the empirical relationship between the $dcp$ and $B$ for the harmonic type III emission, and (2) from the observed quasi-periodicity of the bursts. Both the methods result in $B approx$ 4.2 G at the location of the 80 MHz plasma level (radial distance $r approx 1.3~rm R_{odot}$) in the active region corona.