FUNDAMENTAL AND HARMONIC EMISSION IN TYPE-III SOLAR RADIO-BURSTS II -DOMINANT-MODES AND DYNAMIC SPECTRA

Recent theoretical estimates of the emissivity of fundamental and harm onic radiation in type III solar radio bursts are combined with calcul ations of electron beam evolution, radiation scattering and propagatio n delays to estimate dynamic spectra at a remote observer The burst in tensity, brightness temperature, temporal evolution, and dominant mode of emission are then calculated. A simple explanation of the recently observed low-frequency cutoff to type III emission is found and it is noted that some type III beams may propagate without significant radi o emission. Criteria for observation of harmonic structure in dynamic spectra are also obtained. The results are shown to be consistent with a wide range of observations.