Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published June 2007 | public
Journal Article

Composition of Anomalous Cosmic Rays

Abstract

The "classic" anomalous cosmic ray (ACR) component originates as interstellar neutral atoms that drift into the heliosphere, become ionized and picked up by the solar wind, and carried to the outer heliosphere where the pickup ions are accelerated to hundreds of MeV, presumably at the solar wind termination shock. These interstellar ACRs are predominantly singly charged, although higher charge states are present and become dominant above ∼350 MeV. Their isotopic composition is like that of the solar system and unlike that of the source of galactic cosmic rays. A comparison of their energy spectra with the estimated flux of pickup ions flowing into the termination shock reveals a mass-dependent acceleration efficiency that favors heavier ions. There is also a heliospheric ACR component as evidenced by "minor" ACR ions, such as Na, Mg, S, and Si that appear to be singly-ionized ions from a source likely in the outer heliosphere.

Additional Information

© 2007 Springer Science+Business Media, Inc. Received: 10 January 2007; Accepted: 16 February 2007; Published online: 5 May 2007. We appreciate discussions with R. Mewaldt and N. Schwadron. This work was supported by NASA under contract NAS7-03001.

Additional details

Created:
August 22, 2023
Modified:
October 26, 2023