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Elemental Composition of the Very Local Interstellar Medium as Deduced from Observations of Anomalous Cosmic Rays

Cummings, A. C. and Stone, E. C. (1990) Elemental Composition of the Very Local Interstellar Medium as Deduced from Observations of Anomalous Cosmic Rays. In: Proceedings of the 21st International Cosmic Ray Conference. Vol.6. Department of Physics and Mathematical Physics, University of Adelaide , Northfield, South Australia, pp. 202-205.

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We present a new determination of the relative abundances of the interstellar neutral atoms CI, NI, 0 I, and Ar I. These abundances are derived from Voyager observations of the energy spectra of the anomalous cosmic ray- (ACR) component (He, C, N, 0, Ne, and Ar), using a new analysis technique. We find that the abundances of NI, 0 I, and Ar I are in good agreement with solar system abundances, while the abundance of CI is ~1/100 of the solar system value, consistent with the expectation that C is mostly ionized in the local interstellar medium. As we have reported earlier, we find no evidence for charge-changing interactions associated with the heliopause region.

Item Type:Book Section
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Cummings, A. C.0000-0002-3840-7696
Stone, E. C.0000-0002-2010-5462
Additional Information:© Organizing Committee of the 21st Int. Cosmic Ray Conference. Provided by the NASA Astrophysics Data System. We thank E. Christian for providing the ACR helium spectrum and M. Allen for a compilation of photoionization cross sections. We thank H. Ogawa for a helpful discussion. This work was supported in part by NASA under contract NAS-7-918 and grant NGR-05-002-160..
Group:Space Radiation Laboratory
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1989-20
Record Number:CaltechAUTHORS:20140714-155302359
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ID Code:47193
Deposited By: Deborah Miles
Deposited On:21 Jul 2014 20:30
Last Modified:20 Feb 2020 14:33

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