Ground Level Enhancement of Cosmic Rays on October 28, 2003: Spectra and Anisotropy

Abstract

Variations in the rigidity spectrum and anisotropy of cosmic rays (CRs) during the ground level enhancement (GLE) of CR intensity on October 28, 2003, are studied on the basis of ground and satellite observations by the worldwide network of CR stations using the spectrographic global survey approach developed at the Institute of Solar and Terrestrial Physics, Siberian Branch, Russian Academy of Sciences. Cosmic ray rigidity spectra are determined for different periods of the considered event. It is shown that acceleration of protons during this GLE was observed up to rigidities of ~10–14 GV, and neither a power law nor an exponential function of the rigidity of particles describes the CR differential rigidity spectra during the event. Analysis indicates that the Earth was in a loop-like structure of the interplanetary magnetic field at the time of the GLE event.