Observations of solar type III radio bursts with the Nancay radioheliograph

Results on the space-time evolution of type III burst sources are summarized (Raoult and Pick, 1979) and observations on the temporal characteristics of the circular polarization are presented. It is shown that type III burst sources can be resolved into narrow components. Complex or very large sources may be explained by the occurrence of electron beams which propagate along different diverging paths. Propagating effects in a scattering corona are not required to explain the observations. The origin of the fundamental-harmonic pairs is briefly discussed.