HR: 09:45h
AN: SH11B-08    [PDF]
TI: Solar Fast-Wind Regions as Sources of Shock Energetic Particle Production
AU: * Kahler, S W
EM: stephen.kahler@hanscom.af.mil
AF: Space Vehicles Directorate VSBXS/Air Force Research Laboratory, 29 Randolph Rd, Hanscom AFB, MA 01731 United States
AB: If production of solar energetic particles (SEPs) near the Sun is due to shocks driven by coronal mass ejections (CMEs), then two factors might favor SEP acceleration in slow rather than fast solar wind streams. The first is that both the Alfven and solar wind flow speeds are higher in the fast-wind streams. The second is that shock seed populations consisting of suprathermal ion tails are generally not present in the fast-wind streams. In an earlier study we used observed fast west-limb or halo CMEs and solar wind O$^{+7}$/O$^{+6}$ ratios to look for differences in associated SEP events between fast CMEs in fast and slow wind. The limited number of fast CMEs in fast-wind regions suggested a possible bias in terms of associated SEP event size and/or CME speed against shock production of SEPs in fast-wind regions. Here we extend the previous study to include fast CMEs in fast-wind regions for two additional years. The results now show no significant bias against SEP production in fast-wind regions. We discuss the implications of this result for shock seed populations and for shock propagation in coronal fast-wind regions.
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2118 Energetic particles, solar
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting