Long-term fluences of energetic particles in the heliosphere

Abstract

We report energy spectra of He, O, and Fe nuclei, extending from ∼0.3 keV/nucleon to ∼300 MeV/nucleon, integrated over the period from the Fall of 1997 to mid-2000. These fluence measurements were made at 1 AU using data from the SWICS, ULEIS, SIS, and CRIS instruments on ACE, and include contributions from fast and slow solar wind, coronal mass ejections, pickup ions, impulsive and gradual solar particle events, acceleration in corotating interaction regions and other interplanetary shocks, and anomalous and galactic cosmic rays. Fluence measurements of six additional species are presented in the energy region from ∼0.04 to ∼100 MeV/nucleon. We discuss the relative contributions of the various particle components, and comment on the shape and time dependence of the measured energy spectra. © 2001 American Institute of Physics.