Solar energetic electrons related to the 28 October 2003 flare

Abstract

We investigate the solar origin of near‐relativistic electrons and protons during the X17.2/4B flare as observed by the Comprehensive Suprathermal and Energetic Particle Analyser (COSTEP) and Three‐Dimensional Plasma (3DP) analyzer experiments on board the SOHO and Wind spacecraft. These observations are combined with ground‐ and space‐based spectral radio data obtained by the Potsdam spectrograph and the Wind/Waves instrument. Additionally, we use measurements of relativistic protons (ground‐level event (GLE)) by neutron monitors (Kiel and Moscow). Timing and electron energy spectrum analysis suggest that there are three separate stages of electron injection into interplanetary space: (1) An injection of radio type III–producing electrons is observed first; (2) an impulsive injection with an almost symmetric time profile with a short duration (∼18 min) is released ∼11 min later, followed by (3) a gradual, long (>1 hour) lasting injection, with an onset ∼25 min after the first type III burst. While the first escaping type III–producing electrons are more likely related to the reconnection processes during the impulsive flare phase, the association of the two delayed electron injections with solar events is not well understood.