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Anomalous Cosmic Rays

Cummings, Alan C. and Stone, Edward C. (2013) Anomalous Cosmic Rays. In: Centenary Symposium 2012: Discovery of Cosmic Rays. AIP Conference Proceedings. No.1516. American Institute of Physics , Melville, N.Y., pp. 97-101. ISBN 978-0-7354-1137-1.

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Anomalous cosmic rays (ACRs) first started showing up in observations 40 years ago. Within a few years a paradigm was developed to explain their origin: they begin their life as interstellar neutral atoms that drift into the heliosphere, become singly ionized by chargeexchange with a solar wind ion or by photoionization, are picked up by the expanding solar wind, and accelerated to the observed energies by diffusive shock acceleration at the solar wind termination shock. This paradigm became widely accepted and withstood the tests of further observations until 16 December 2004, when Voyager 1 crossed the termination shock and didn't find their source. In August 2007, Voyager 2 crossed the termination shock and also did not find the source location of ACRs. Clearly, the source location was not at the termination shock where the two Voyagers crossed. Alternative models have been proposed with acceleration elsewhere on the shock or by other acceleration processes in the heliosheath. We discuss the latest observations of ACRs from the Voyager spacecraft and hopefully shed more light on this ongoing puzzle.

Item Type:Book Section
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URLURL TypeDescription DOIArticle
Cummings, Alan C.0000-0002-3840-7696
Stone, Edward C.0000-0002-2010-5462
Additional Information:© 2013 American Institute of Physics. We thank Jon Ormes for his assistance in writing this paper. This work was supported by NASA under contract NNN12AA012.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:cosmic rays, anomalous cosmic rays, solar wind termination shock
Series Name:AIP Conference Proceedings
Issue or Number:1516
Classification Code:PACS: 96.50.Ek, 96.50.Pw, 96.50.S-,, 96.50.Vg, 96.50.Xy, 96.50.Ya, 96.20Br
Record Number:CaltechAUTHORS:20130226-134144383
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Official Citation:Anomalous cosmic rays Alan C. Cummings and Edward C. Stone AIP Conf. Proc. 1516, pp. 97-101; doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37151
Deposited By: Ruth Sustaita
Deposited On:26 Feb 2013 22:59
Last Modified:09 Nov 2021 23:27

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