IV. Results from Hinotori and P78-1

Abstract

Hinotori observed 720 flares through its operation February 1981-October 1981. General discussions of the results were given in two symposia: the Hinotori Symposium (ISAS 1982) and the U.S.-Japan Seminar (de Jager & Švestka 1983). The hard x-ray imaging made at the effective energy 20-35 keV showed a wide variety of morphology. Many flares (22 out of 30 events) showed single source structure, either compact (12) or extended (10) in the spatial resolution of 15 arc sec (Takakura et al. 1983a, Ohki et al. 1983, Takakura 1984). Evidences are given in some limb events that the main source is located in the high corona (1-4 x 104 km) (Takakura et al. 1983b). The extended single source could be the whole coronal loops which may include footpoints, but the maximum brightness is near the loop top. In some events (8 out of 30), weak subsource(s) which sould be identified with the footpoint(s) appear intermittently (Tsuneta et al. 1983). Takakura et al. (1984) found that the extended single source becomes compact and slightly shifts to higher altitudes in later phases of the impulsive burst (5 out of 10 events). Tanaka (1984), Takakura (1984), and Tanaka S Zirin (1984) argued that the hard x-ray morphology of the impulsive burst is consistent with the non-thermal electron beam model in high density corona. Sakurai (1983) investigated magnetic field structures of the hard x-ray sources based on the potential field calculations. Timing between the hard x-ray and microwave in the impulsive bursts was examined by Takakura et al. (1983c), who found correlated subsecond time structures and also by Takakura et al. (1983d), who found a long (5-10 s) delay of the peaks at 17 GHz and E > 300 keV to the peak at E < 100 keV. Kurokawa (1983) showed detailed coincidence between the hard x-ray spikes and Hα brightenings.