A long-enduring multi-source burst at 17 GHz and its relation to a type IVm-dm burst with spectral fine features

A proton-event-associated microwave burst occurred on November 10, 1978 and was observed with the 17 GHz interferometer at Nobeyama. The burst had a very broad extent of about 4.5 arc and consisted of at least four separate sources. The time evolutions of the individual sources were almost independent of each other. We suggest that the sources are fallen into two distinct types as follows: (i) The two-ribbon-associated sources are characterized by the source expansion in size and the relatively flat microwave spectrum, both of which can be explained by thermal emission from hot condensed plasma in the magnetic arcades whose legs are seen as the two-ribbon H flare, and (ii) the spot-related sources are characterized by the high polarization degree with a compact unipolar structure, the rapid time variation, and the inverted-U shape microwave spectrum. The intimate relation of the latter sources to the evolution of the associated type IV_m-dm burst with spectral fine features is also discussed.