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Effects of Solar Modulation on the Low-Energy Cosmic Ray Antiproton/Proton Ratio

Labrador, A. W. and Mewaldt, R. A. (1996) Effects of Solar Modulation on the Low-Energy Cosmic Ray Antiproton/Proton Ratio. Astrophysical Journal, 480 (1). pp. 371-374. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:20140703-220710670

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Abstract

We examine the transport of cosmic-ray protons and anitprotons from local interstellar space through the interplanetary medium to Earth and discuss the resulting effects on the low-energy antiproton/proton ratio at 1 AU. We find that the antiproton/proton ratio at energies above ~3 GeV is a useful diagnostic of cosmic-ray transport in the Galaxy. However, at energies below ~1 GeV the expected ratio is much more uncertain because of differences in the energy spectra and the resulting relative modulation of protons and antiprotons over the solar cycle, as well as uncertainties in the interstellar spectra. Using calculated interstellar spectra as references, we find that the antiproton/proton ratio at low energies varies by as much as an order of magnitude over the solar cycle. As a result, we recommend that attention be given instead to interpretation of the measured cosmic-ray antiproton energy spectrum rather than to the antiproton/proton ratio.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://iopscience.iop.org/0004-637X/480/1/371/PublisherArticle
http://dx.doi.org/10.1086/303960DOIArticle
http://adsabs.harvard.edu/abs/1997ApJ...480..371LADSArticle
Additional Information:© 1997. The American Astronomical Society. Received 1996 July 26; accepted 1996 November 12. This work was funded by NASA under grant NAGW-1919. One of us (A. L.) is grateful for a NASA Graduate Fellowship. We thank F. McDonald, W. McGuire, and P. Schuster for providing us with IMP 8 proton data. We thank T. Gaisser, R. Schaefer, E. Stone, R. Streitmatter, and W. R. Webber for useful discussions.
Group:Space Radiation Laboratory
Funders:
Funding AgencyGrant Number
NASANAGW-1919
NASA Graduate FellowshipUNSPECIFIED
Subject Keywords:cosmic rays—interplanetary medium
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1996-25
Record Number:CaltechAUTHORS:20140703-220710670
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140703-220710670
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46841
Collection:CaltechAUTHORS
Deposited By: Deborah Miles
Deposited On:23 Jul 2014 17:43
Last Modified:23 Jul 2014 17:43

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