An Acceleration/Modulation Model for Anomalous Cosmic-Ray Hydrogen in the Heliosphere

Abstract

A modulation model that includes shock acceleration of cosmic rays at the solar wind termination shock is used to study the characteristics of anomalous cosmic ray hydrogen, guided by the 1987 solar minimum spectra as observed by IMP 8, Voyager 2, and Pioneer 10. This first attempt at a comprehensive data fit excludes the effects of drifts and must therefore be considered as preliminary. It is found that an anomalous component dominates hydrogen spectra in the outer heliosphere but, due to large radial gradients, the anomalous contribution in the inner heliosphere is negligible. Similar model fits are shown for anomalous cosmic ray He and O to demonstrate the degree of internal consistency of the model.