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Observations of Geomagnetically Trapped Anomalous Cosmic Rays by SAMPEX

Selesnick, R. S. and Cummings, J. R. and Mewaldt, R. A. (1996) Observations of Geomagnetically Trapped Anomalous Cosmic Rays by SAMPEX. In: Proceedings of the Workshop on the Earth's Trapped Particle Environment. AIP Conference Proceedings. No.383. American Institute of Physics , New York, NY, pp. 155-160. ISBN 1-56396-540-2.

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he first detailed measurements of a belt of geomagnetically trapped heavy ions that originated as interplanetary anomalous cosmic rays (ACRs) are being made by the polar orbiting satellite SAMPEX. The singly ionized interplanetary ACRs are trapped after losing electrons in the upper atmosphere. Their subsequent lifetime against energy loss by ionization of the atmosphere allows them to reach a substantially higher intensity than in interplanetary space. The ACR composition, which includes only elements with high first ionization potentials, is reflected in the trapped ACRs with some bias due to the trapping mechanism. The elements O, N, and Ne are present, while the lower atomic number elements, He and C, are either absent or substantially depleted relative to their interplanetary abundances. The trapping mechanism also determines the location of the ACR belt, which is confined to a narrow region near L=2, and the pitch‐angle distribution of the trapped ACRs, which is nearly isotropic except for the well‐defined loss cones. The intensities of the trapped and interplanetary ACRs have been measured by SAMPEX since its July, 1992 launch. Both have been steadily increasing with the approach of the minimum of the solar sunspot cycle.

Item Type:Book Section
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Mewaldt, R. A.0000-0003-2178-9111
Additional Information:© 1996 American Institute of Physics. Published online 25 July 1996. This work was supported by NASA under contract NAS5-30704 and grant NAGW-1919.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Non-Subject Keywords:cosmic rays, geomagnetic anomalies, collisional energy loss, electrons, elemental abundances
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1994-12
Series Name:AIP Conference Proceedings
Issue or Number:383
Record Number:CaltechAUTHORS:20140609-164123573
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46168
Deposited By: Deborah Miles
Deposited On:13 Jun 2014 04:16
Last Modified:10 Nov 2021 17:21

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