HR: 1330h
AN: SH23A-06    [Abstracts]
TI: Anomalous Cosmic Ray Oxygen Intensity Gradients Between 1 AU and Voyager During the Cycle 23 Solar Maximum
AU: * Leske, R A
EM: ral@srl.caltech.edu
AF: California Institute of Technology, Mail Code 220-47, Pasadena, CA 91125 United States
AU: Cummings, A C
AF: California Institute of Technology, Mail Code 220-47, Pasadena, CA 91125 United States
AU: Cohen, C M
AF: California Institute of Technology, Mail Code 220-47, Pasadena, CA 91125 United States
AU: Mewaldt, R A
AF: California Institute of Technology, Mail Code 220-47, Pasadena, CA 91125 United States
AU: Stone, E C
AF: California Institute of Technology, Mail Code 220-47, Pasadena, CA 91125 United States
AU: Wiedenbeck, M E
AF: Jet Propulsion Laboratory, MS 169-327, Pasadena, CA 91109 United States
AU: von Rosenvinge, T T
AF: NASA/Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 United States
AB: The Solar Isotope Spectrometer (SIS) on NASA's Advanced Composition Explorer (ACE) has measured the composition of energetic nuclei at 1 AU over an energy interval of ~10 to 100 MeV/nucleon for more than 7 years. During solar quiet times at solar minimum, the particle fluxes at the low energy end of this interval are dominated by anomalous cosmic rays (ACRs). After being suppressed by a factor of ~100 or more from 2001 through 2003 during solar maximum, ACR intensities are once again recovering at 1 AU. However, their intensities are lower relative to higher rigidity galactic cosmic rays than they were during entry into solar maximum in 1998-2000. We review ACE/SIS measurements of the ACR composition and spectra obtained during solar minimum and of the variation of the ACR O intensity at 1 AU during the solar cycle. Using the 1 AU ACR oxygen intensity along with that measured by the Voyager 1 and 2 spacecraft in the outer heliosphere, we obtain the radial ACR intensity gradient during solar maximum and compare it with the galactic cosmic ray gradient during that time. This work was supported by NASA at Caltech (under grants NAG5-6912 and NAS7-03001), JPL, and GSFC.
DE: 2104 Cosmic rays
DE: 2114 Energetic particles, heliospheric (7514)
DE: 2124 Heliopause and solar wind termination
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2005 Joint Assembly