HR: 1330h
AN: SH13A-12    [Abstracts]
TI: Comparison of Heliospheric Magnetic Field Lines from PFSS Models with SEP Observations
AU: * Nitta, N V
EM: nitta@lmsal.com
AF: LMSAL Dept/ADBS B/252, 3251 Hanover Street, Palo Alto, CA 94304 United States
AU: Liu, Y
EM: yliu@quake.stanford.edu
AF: Stanford University, HEPL, Stanford, CA 94305 United States
AU: DeRosa, M L
EM: derosa@lmsal.com
AF: LMSAL Dept/ADBS B/252, 3251 Hanover Street, Palo Alto, CA 94304 United States
AB: Impulsive Solar Energetic Particle (SEP) events are thought to come locally from solar flares, in contrast with large gradual SEP events that are attributed to extended shocks driven by fast CMEs. For several impulsive SEP events, we identified the possible solar sources, using the timings of type III bursts. The solar sources thus indentified tend to be minor brightenings, sometimes not even detectable by the GOES X-ray Spectrometer. We found whether the source active region is open to the heliosphere, using potential field source surface (PFSS) models. We also traced field lines from the spacecraft observing SEPs to the source surface assuming constant solar wind speed, and then mapped them to the photosphere using PFSS models. In a number of cases, these traced field lines go close to the flare site. In other cases, their foot-points are far from the flare, or the source active region shows no open field lines. We interpret these various results in terms of different magnetograms for PFSS modeling, and assumptions used in the models.
DE: 7509 Corona
DE: 7514 Energetic particles (2114)
DE: 7519 Flares
DE: 7524 Magnetic fields
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2005 Joint Assembly