A comparative study of ion characteristics in the large gradual solar energetic particle events of 2002 April 21 and 2002 August 24

Solar energetic particles (SEPs) provide an opportunity to study in detail the processes of particle acceleration and transport that are ubiquitous in astrophysical plasmas. Tylka et al. focused on the problem of SEP spectral and compositional variability at energies above a few tens of MeV per nucleon. They motivated their study with two large, gradual SEP events, 2002 April 21 and 2002 August 24, which have similar fast coronal mass ejections (CMEs) and flares but nevertheless illustrate the extremes of high-energy behavior. In this paper, we present additional detailed comparisons between the ion characteristics of these events. These results should be helpful in developing and testing new SEP models, which are currently under development.