Impulsive and extended acceleration in the 1977 November 6 solar flare Original Research Article

Yohkoh observed strong gamma-ray emission from a flare (X9.4/2B) on November 6, 1997. The emission was impulsive and lasted for about 4 min (11:52–11:56 UT). The spectrum exhibits gamma-ray lines and extends up to a few tens of MeV. The Oriented Scintillation Spectrometer Experiment (OSSE) on board the Compton Gamma-Ray Observatory (CGRO) missed the peak phase of gamma-ray flare but detected significant solar neutrons between 12:08 and 12:28 UT. In order to explain the OSSE neutron time profile, we propose an extended neutron production. We find a continued gamma-ray production after the peak phase from the Yohkoh result, supporting our proposal. We discuss the possibility that particle acceleration is associated with a magnetic reconnection and its site moves up with time.