HR: 10:50h
AN: SH52B-03    [Abstracts]
TI: Multispacecraft Observations of "Dropouts" in Impulsive Events
AU: * Chollet, E
EM: echollet@lpl.arizona.edu
AF: Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721-0092, United States
AU: Giacalone, J
EM: giacalon@lpl.arizona.edu
AF: Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721-0092, United States
AU: Mason, G
EM: Glenn.Mason@jhuapl.edu
AF: Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Rd., Laurel, MD 20723-6099, United States
AB: We will present multispacecraft observations and analysis of intensity "dropouts" in solar-energetic particle (SEP) events. When seen by ACE/ULEIS and Wind/STEP, flare-related energetic ion events display a velocity dispersion, with the higher velocity particles arriving earlier than the lower velocity particles. In 2000, Mazur et al. first reported "dropouts", consisting of sudden decreases in intensity occuring simultaneously across all energies and lasting on the order of a few hours. In that paper and the accompanying one by Giacalone et al., they propose that these dropouts occur at the passage of flux tubes unconnected to the flare source that have been mixed in with full flux tubes due to field line random walk. We have continued this analysis by considering the entire time period when both of these spacecraft are observing, creating a list of observed impulsive flare-related dispersions with and without dropouts. We will present several additional examples of these events and relate them to the relative spacecraft orientations, as spacecraft which are separated by more than a correlation scale in the direction perpendicular to the Earth-sun line should see different flux tubes. We will also discuss the frequency of these dropouts and how it relates to the amount of field line mixing.
DE: 2114 Energetic particles (7514)
DE: 2134 Interplanetary magnetic fields
DE: 7514 Energetic particles (2114)
DE: 7859 Transport processes
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting