Energetic (∼ 1 to 50 MeV) protons associated with Earth-directed coronal mass ejections

Abstract

During the period from January through mid-May, 1997, four large Earth-directed CMEs were observed by the Large Angle Spectroscopic Coronograph (LASCO). These CMEs were associated with long-lasting fluxes of > 1.6 MeV protons detected by the Energetic and Relativistic Nuclei and Electron instrument (ERNE). However, the magnitudes of energetic proton events differed dramatically on different occasions. In strong proton events, production of 10-50 MeV protons started during expansion of the coronal Moreton wave in the western hemisphere of the Sun. The new SOHO observations suggest that potentialities of CMEs to produce energetic particles in the interplanetary medium crucially depend on the previous evolution of the explosion below ∼2R⊙. Forecasting of the near-Earth > 10 MeV proton intensity requires multiwavelength observations of the early phase of an event, particularly the Extreme-ultraviolet Imaging Telescope (EIT) observations. Copyright 1998 by the American Geophysical Union.