HR: 0800h
AN: SH51D-0299    [Abstracts]
TI: Secondary Electron Emission from Aggregate Dust Particles
AU: * Kimura, H
EM: kimura@uni-muenster.de
AF: Institut fuer Planetologie, Westfaelische Wilhelms - Universitaet, Wilhelm-Klemm-Str. 10, Muenster, 48149 Germany
AU: Mann, I
EM: imann@uni-muenster.de
AF: Institut fuer Planetologie, Westfaelische Wilhelms - Universitaet, Wilhelm-Klemm-Str. 10, Muenster, 48149 Germany
AB: Dust particles immersed in plasma inevitably carry electric charges on their surfaces as a consequence of their interactions with plasma particles. Secondary electron emission is one of the most important charging mechanisms in the region of high-temperature plasma such as the vicinity of the sun and the heliospheric boundary. Furthermore, its importance is elevated for small grains whose radii are comparable to the escape length of electrons. Available information indicates that dust particles in the solar system are fluffy aggregates consisting of submicron grains rather than compact spheres. The number of secondary electrons emitted from fluffy aggregate particles is expected to be smaller than that from compact spherical particles, because electrons emitted toward a void in a fluffy particle can be absorbed within the particle again. Therefore, one needs to take into account the morphology of dust grains for evaluating the secondary electron yield. We will present a simple method to numerically estimate the secondary electron yield for fluffy dust aggregates and discuss the importance of particle morphology for the determination of the secondary electron current.
DE: 2124 Heliopause and solar wind termination
DE: 2129 Interplanetary dust
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting