HR: 0830h
AN: SH11D-1138    [PDF]
TI: Extended Injection Histories of Near-Relativisitic Solar Electrons and Their Relation to SEP Ion Events
AU: * Haggerty, D K
EM: dennis.haggerty@jhuapl.edu
AF: Johns Hopkins U./Applied Physics Lab., 11100 Johns Hopkins Rd., Laurel, MD 20723 United States
AU: Roelof, E C
EM: edmond.roelof@jhuapl.edu
AF: Johns Hopkins U./Applied Physics Lab., 11100 Johns Hopkins Rd., Laurel, MD 20723 United States
AB: Energetic solar electrons provide important information on the acceleration and release of all classes of solar energetic particles (SEPs). The relationships of their intensities to ion abundances and isotopic composition (e.g., $^{3}$He/$^{4}$He) have been studied for decades. Their near-light speed and nearly scatter-free propagation out to 1AU preserve many details of their injection into the solar wind. Recently we have been exploiting the high timing and angular resolution of the ACE/EPAM measurements of 38-315 keV electrons [Haggerty and Roelof, {\it ApJ., 579}, 841, 2002]. We now are able to reconstruct the injection histories of beam-like electrons extending well into the SEP events. This is accomplished by subtracting out the back-scattered electrons that have returned from magnetic irregularities beyond 1 AU, mirrored inside 1AU, and then returned to 1AU. The difference between the total outgoing intensity and that of this mirrored component (time delayed) gives the intensity of the electrons that are still arriving directly from the Sun. The mathematical relation is j$_{s}$($\mu$,t-s/v)=j($\mu$,t)-j(-$\mu$,t-2$\tau$), where $\mu$ is the pitch cosine (measured positive anti-sunwards), s is the trajectory distance traveled at velocity v, and $\tau$ is the time for a particle with pitch cosine $\mu$$ <$0 at 1AU to reach its mirroring point inside 1AU. We find that the injection of solar electrons often lasts for considerably more than an hour at significant intensities. This analysis yields new diagnostics of the acceleration/release process, which we have ascribed to CME-associated shock acceleration [Simnett, Roelof, and Haggerty, {\it ApJ, 579}, 854, 2002]. The relation of electron injection to ion injection and $^{3}$He/$^{4}$He variations is the subject of an ongoing joint study [Mewaldt et al., {\it28$^{th}$ICRC, SH1.3}, 17, 2003].
DE: 2100 INTERPLANETARY PHYSICS
DE: 2114 Energetic particles, heliospheric (7514)
DE: 6200 PLANETOLOGY: SOLAR SYSTEM OBJECTS (New field)
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7800 SPACE PLASMA PHYSICS
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting