Fe/O ratio variations during the disturbed stage in the development of the solar cosmic ray fluxes: Manifestations of the first ionization potential effect in the solar cosmic ray composition

Abstract

The accelerated particle energy spectra in different energy intervals (from 0.06 to 75.69 MeV n^–1) have been constructed for various powerful flare events (1997–2006) with the appearance of solar cosmic rays (SCRs) based on the processing of data from the Advanced Composition Explorer (ACE) and WIND spacecraft. Flares were as a rule accompanied by coronal mass ejections. Different specific features in the particle spectra behavior, possibly those related to different acceleration processes, were revealed when the events developed. The Fe/O abundance ratio in different energy intervals during the disturbed development of flareinduced fluxes has been qualitatively estimated. It has been established that ground level event (GLE) fluxes represent an individual subclass of gradual events according to the character of Fe/O variations. The manifestations of the first ionization potential (FIP) effect in the composition of SCRs during their propagation have been qualitatively described.