Time-Variations of 17GHz Radio Bursts by Multi-Source Structures

Abstract

Four multi-source radio bursts observed with the new 17GHz interferometer at Nobeyama are analyzed and presented from the point of view of their time-variations.Three of them (Sep. 6, 1978; Oct. 9, 1978; and Feb. 17, 1979) were essentially of an impulsive nature and all showed distinct double-source structures. Their polarization structures and time-variations are discussed and compared with type III and type II burst occurrences. The results of the comparison suggest either that electron accelerating regions moved across magnetic lines of force or that a rapid magnetic field rearrangement occurred near an accelerating region.A quite different type of multi-source radio bursts was observed on Nov.10,1978. It had a long duration of several hours and was associated with type IV bursts at metric and decimetric wavelengths. At least five radio sources were observed to appear at 17GHz. A detailed description of this event is presented in comparison with the evolution of both Hα-flare and type IV bursts.