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Solar are emission was measured at 212 GHz in the submillimeter range by the Submillimeter Solar Telescope in the 1.2-18 GHz microwave range by the Owens Valley Solar Array and in the gamma-ray energy range (continuum) by experiments on board the Yohkoh ( > 1. 2 MeV) and Shenzhou 2 ( > 0.2 MeV) satellites. At the burst onset, the submillimeter and microwave time profiles were well correlated with gamma rays to the limit of the temporal resolution (less than or equal to10 s). At 212 GHz, fast pulses ( 1. 2 MeV), attaining nearly 50 pulses per minute at the maximum. These results suggest that gamma rays might be the response to multiple rapid pulses at 212 GHz and might be produced at different sites within the flaring region.

The Solar X-Ray/Cosmic Gamma-Ray Burst Experiment aboard the interplanetary spacecraft Ulysses has provided extensive observations of solar hard X-ray flares from a variety of angles with respect to the Sun-Earth line. During the period 1991 October-1993 June, Ulysses observed 13 flares that were also observed by the X-ray instruments aboard the Japanese satellite Yohkoh located near Earth. At least 12 flares were in full view of both the spacecraft. Eight flares, for which hard X-ray spectra were available, are examined to determine the directivity of the 20-125 keV hard X-ray sources in solar flares. They include one flare for which the view angles of Ulysses and Yohkoh were 80° and 25°, respectively. No evidence of systematic directivity was found within the uncertainty (a factor of ~2) of these measurements. These and other observations of directivity at higher energies are consistent with a nearly isotropic distribution of energetic electrons in most solar flares.

The Yohkoh satellite has registered X-ray spectra of two solar flares with a linelike feature in the region 400-500 keV. Analysis shows that this feature can be interpreted as gamma-ray lines from excited 7Li and 7Be produced from α+ α reactions. The 7Li production rate in the solar atmosphere is estimated from these observations. The lower limit on the flare-produced 7Li abundance on the Sun is determined. This value is several times less than that obtained from optical observations of the solar atmospheric 7Li.

Les observations, par le satellite Hinotori, de 8 eruptions solaires Rγ sont presentees. La forme spectrale et le nombre de protons acceleres de certaines de ces eruptions sont determines et compares a ceux observes dans l'espace interplanetaire. Intervention presentee au Second Workshop on Impulsive Solar Flares, a l'Universite de New Hampshire, du 26 au 28 septembre 1988.