Transport of energetic particles derived from a detailed analysis of the September 29, 1989 solar flare

Abstract

The exceptionally energetic flare of September 29, 1989, at 11:33 UT has been analyzed using neutron monitor data and the energy resolved particle data collected by the GOES satellites. A picture emerges of a dual injection in the impulsive, explosive phase of the flare process, with an additional gradual source mechanism traced to the shock front of the expanding cloud in the interplanetary space. The transport mechanism needed is a two-dimensional diffusive transport in the solar corona convoluted with the one dimensional streaming along the magnetic field lines. We find that only the impulsive acceleration phase is capable of accelerating particles to the GeV region; the major role of the coronal shock is to facilitate the fast transport of the flare accelerated particles into interplanetary space, and the interplanetary shock is only capable of accelerating particles in the MeV region.