OSSE observations of solar flares

The Oriented Scintillation Spectrometer Experiment (OSSE) on the Compton Gamma Ray Observatory (CGRO) provides solar‐flare observation capabilities that represent a significant improvement over previous experiments. In this paper, we discuss the OSSE solar observation modes, give an overview of the solar‐flare observations to date, and discuss in some detail the observations obtained during the June 1991 CGRO solar Target of Opportunity. We show evidence for time structure of flare hard X‐ray (≳100 keV) emission as short as tens of msec. Several nuclear deexcitation lines along with emission ≳10 MeV were seen from the four GOES X10+ flares observed by OSSE. Neutrons were observed from two of the flares. Preliminary results from a search of the OSSE flare database for nuclear emission from weak flares are presented and compared to results from a similar search of the Solar Maximum Mission Gamma‐Ray Spectrometer database.