George Gloeckler University of Maryland, College Park, Maryland, USA University of Michigan, Ann Arbor, Michigan, USA
A variety of heliospheric ion populations -- from Anomalous Cosmic Rays (ACRs) to particles accelerated in Corotating Interaction Regions (CIRs) -- have now been observed and studied for several decades. It had been commonly assumed that the solar wind was the source for all of these populations, except for the ACRs, and that shock acceleration produced the energetic particle observed, including the ACRs. For the ACRs the source that has been proposed a long time ago was the interstellar gas penetrating deep into the heliosphere. Recent measurements of the composition and spectra of suprathermal ions, primarily from Ulysses, ACE and Wind, indicate that pickup ions are likely to be an important source not only of the ACRs but for other heliospheric ion populations as well. In particular, the newly discovered "Inner Source" pickup ions may be a significant source for particles accelerated in the inner heliosphere. Furthermore, the omnipresent suprathermal tails seem to tell us that shock acceleration may not be the primary mechanism energizing particles in the heliosphere. We will present recent observations and discuss implications for injection and particle acceleration.