A Caltech Library Service

A Study of Temporal and Radial Dependencies of the Anomalous Helium and Oxygen Nuclei

Webber, W. R. and McDonald, F. B. and Mewaldt, R. A. (1981) A Study of Temporal and Radial Dependencies of the Anomalous Helium and Oxygen Nuclei. In: Proceedings of the 17th International Cosmic Ray Conference. Vol.10. CEN Saclay , Gif-sur-Yvette, France, pp. 92-95.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


The intensity of the low energy anomalous Helium and Oxygen components has been continuously monitored by telescopes on the Pioneer 10 and IMP 7 and 8 spacecraft since 1972. After a period of relatively small temporal changes at earth between 1972 and 1978, during which it was possible to study the radial gradients of these components out to ~ 15 AU, large temporal changes were observed in 1978-1980 associated with the onset of the new solar modulation cycle. During this time period the anomalous He and 0 intensities at Pioneer 10 have decreased by a factor > 10, however, both anomalous components were still present in the summer of 1980 at ~ 20AU. At the earth similar large intensity changes have occurred. At Pioneer 10 the relative modulation of He nuclei is ~1.4x that of 0 nuclei at the same energy/nuc during this time period.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Mewaldt, R. A.0000-0003-2178-9111
Contact Email
Additional Information:© IUPAP. Provided by the NASA ADS. This work was sponsored by various NASA grants at GSFC, UNH, and Caltech.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:Helium, Nuclei (Nuclear Physics), Oxygen, Particle Flux Density, Primary Cosmic Rays, Radial Distribution, Solar Activity Effects, Time Dependence, Anomalies, Explorer Satellites, Particle Energy, Particle Telescopes, Pioneer 10 Space Probe
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1981-23
Record Number:CaltechAUTHORS:20140417-154502318
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45044
Deposited By: SWORD User
Deposited On:22 Apr 2014 19:00
Last Modified:22 Nov 2019 09:58

Repository Staff Only: item control page