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Anomalous Cosmic Ray Oxygen Gradients Throughout the Heliosphere

Cummings, A. C. and Mewaldt, R. A. and Blake, J. B. and Cummings, J. R. and Franz, M. and Hovestadt, D. and Klecker, B. and Mason, G. M. and Mazur, J. E. and Stone, E. C. and von Rosenvinge, T. T. and Webber, W. R. (1995) Anomalous Cosmic Ray Oxygen Gradients Throughout the Heliosphere. Geophysical Research Letters, 22 (4). pp. 341-344. ISSN 0094-8276. doi:10.1029/94GL03343.

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We have used data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), Ulysses, Voyager 1, Voyager 2, and Pioneer 10 spacecraft to determine the radial and latitudinal gradients of anomalous cosmic ray oxygen at 10 MeV/nuc during the last half of 1993. These five spacecraft cover radial distances from 1 AU (SAMPEX) to 58 AU (P10) and latitudes to 41 deg S (Ulysses) and 32 deg N (V1). We find that the radial gradient is a decreasing function of radial distance, approximately r-n, with n = 1.7 +/- 0.7. The large-scale radial gradient between the inner and outer heliosphere is much smaller than it was during the last solar minimum period in approximately 1987. The latitudinal gradient is small and positive, 1.3 +/- 0.4 %/deg, as opposed to the large and negative latitudinal gradients found during 1987, but similar to the small positive latitudinal gradient measured during 1976 for anomalous cosmic ray helium. These observations confirm that effects of curvature and gradient drift in the large scale magnetic field of the Sun are important for establishing the three-dimensional intensity distributions of these particles in the heliosphere during periods of solar minimum conditions

Item Type:Article
Related URLs:
URLURL TypeDescription
Cummings, A. C.0000-0002-3840-7696
Mewaldt, R. A.0000-0003-2178-9111
Mason, G. M.0000-0003-2169-9618
Stone, E. C.0000-0002-2010-5462
Additional Information:© 1995 American Geophysical Union. Paper number 9401GL03343. This work was supported by NASA under contracts NAS7-918, NAS5-30704, JPL contract 958748, and Agreement 26979B. This work was also supported by the MPG and BMFT under grant numbers Ol0Nl990, 500N87037, 500C90021, and 500N91050.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Bundesministerium für Forschung und Technologie (BMFT)Ol0Nl990
Bundesministerium für Forschung und Technologie (BMFT)500N87037
Bundesministerium für Forschung und Technologie (BMFT)500N87037
Bundesministerium für Forschung und Technologie (BMFT)500C90021
Bundesministerium für Forschung und Technologie (BMFT)500N91050
Max Planck GesellschaftUNSPECIFIED
Non-Subject Keywords:Abundance, Anomalies, Cosmic Rays, Flux (Rate), Gradients, Heliosphere, Interplanetary Medium, Oxygen, Energy Spectra, Interplanetary Magnetic Fields, Pioneer 10 Space Probe, Radial Distribution, Solar Activity Effects, Ulysses Mission, Voyager 1 Spacecraft, Voyager 2 Spacecraft
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1995-1
Issue or Number:4
Record Number:CaltechAUTHORS:20140612-094752170
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46231
Deposited By: Deborah Miles
Deposited On:13 Jun 2014 19:48
Last Modified:10 Nov 2021 17:22

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