Published 1999
| public
Journal Article
Anomalous cosmic rays: Observations
- Creators
-
Cummings, A. C.
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Stone, E. C.
Abstract
The latitudinal gradients of galactic cosmic ray protons and anomalous cosmic ray (ACR) helium appear to be symmetrical about a plane displaced ∼10° south of the heliographic equator, similar to the displacement of the heliospheric current sheet (HCS). The radial gradient of ∼10 MeV/nuc ACR oxygen in the outer heliosphere is correlated with the amplitude of the tilt of the HCS. The form of the correlation depends on the magnetic polarity of the solar cycle. The observed radial gradients are the basis for an empirical model that reasonably describes the modulation of ∼2–3 GV ACR oxygen at low heliographic latitudes over a 25-year period.
Additional Information
© 1999 COSPAR. Published by Elsevier Science Ltd. We appreciate the website at the Wilcox Solar Observatory (http://quake.stanford.edu/~wso) from which the tilt angle data were extracted. We also obtained IMP 8 solar wind speed data from the website maintained by the Space Plasma Group of the Massachusetts Institute of Technology (ftp://space.mit.edu/pub/plasma/imp/www/imp.html). We thank W. R. Webber for providing the P10 oxygen data from 1978 onwards. This work was supported by NASA under contract NAS7-918 and grant NAGW-1919.Additional details
- Eprint ID
- 44015
- Resolver ID
- CaltechAUTHORS:20140226-111247648
- NAS7-918
- NASA
- NAGW-1919
- NASA
- Created
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2014-02-28Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 1999-58