Observation of solar energetic particle (SEP) events associated with narrow CMEs

Abstract

We report here on two proton energetic particle events observed by the Energetic and Relativistic Nuclei and Electron (ERNE) instrument on the Solar and Heliospherical Observatory (SOHO). Both events were impulsive (SEP) events with intensities of > 10 -3 cm -2 sr -1 s -1 MeV -1 at an energy range of tens of MeVs and were associated with CMEs of angular widths < 60° and linear speed of >800 kms-1. In one of the events there was no associated solar flare, which indicates that the first injected protons were completely due to the associated CME and in the second event the associated solar flare was an impulsive M1.1 class flare and the calculated first injection time for protons of energies ∼36MeV and propagating along 1.2AU path length, was close to the liftoff time of the CME. These observations are inconsistent with the view presented in some studies that narrow fast CME are not associated with SEP events. © Author(s) 2012.