HR: 1340h
AN: SH43A-1083    [Abstracts]
TI: Pioneer Observations of ICMEs in the Outer Heliosphere
AU: * Gazis, P R
EM: pgazis@mail.arc.nasa.gov
AF: San Jose State University Foundation, NASA Ames Research Center, Moffett Field, CA 94035 United States
AB: Interplanetary coronal mass ejections (ICMEs) are an important physical process throughout the heliosphere. They are associated with a broad range of phenomena, such as particle acceleration and cosmic ray modulation. They may also play an important role in the dynamics and evolution of the solar wind during periods of high solar activity. Until recently, there have been few direct observations of ICMEs at heliocentric distances greater than 1 AU. Since then, Paularena et al. [2001], Wang and Richardson [2004], and others have demonstrated that it is possible to use alpha density enhancements on proton temperature depressions to perform surveys of ICMEs at the Voyager and Ulysses spacecraft during Solar Cycles 22 and 23. Solar wind spectra from the Pioneer 10 spacecraft are examined to perform a comparable survey of ICMEs at this spacecraft. Preliminary results suggest that existing alpha particle and proton temperature observations are sufficiently sensitive to identify the signatures of possible ICMEs out to heliocentric distances of 5-10 AU and 10-15 AU respectively. These observations allow us to extend our knowledge of the radial and temporal variation of ICMEs in the outer heliosphere during the declining phase of Solar Cycle 20 and the ascending phase of Solar Cycle 21.
DE: 7513 Coronal mass ejections
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2162 Solar cycle variations (7536)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting