Long-duration high-energy proton events observed by GOES in October 1989

Abstract. We consider the prolonged injection of the high-energy (>10 MeV) protons during the three successive events observed by GOES in October 1989. We apply a solar-rotation-stereoscopy approach to study the injection of the accelerated particles from the CME-driven interplanetary shock waves in order to find out how the effectiveness of the particle acceleration and/or escape depends on the angular distance from the shock axis. We use an empirical model for the proton injection at the shock and a standard model of the interplanetary transport. The model can reproduce rather well the observed intensity–time profiles of the October 1989 events. The deduced proton injection rate is highest at the nose of the shock; the injection spectrum is always harder near the Sun. The results seem to be consistent with the scheme that the CME-driven interplanetary shock waves accelerate a seed particle population of coronal origin.

Key words. Interplanetary physics · Energetic particles · Solar physics · astrophysics and astronomy · Flares and mass ejections