HR: 0800h
AN: P51B-0495    [Abstracts]
TI: Laboratory Studies of the Lunar Surface Plasma Sheath and Methods for in situ Plasma Measurements
AU: * Wang, X
EM: xu.wang@colorado.edu
AF: Department of Physics, U.of Colorado, Boulder, CO 80309, United States
AU: Horanyi, M
EM: horanyi@colorado.edu
AF: Department of Physics, U.of Colorado, Boulder, CO 80309, United States
AU: Horanyi, M
EM: horanyi@colorado.edu
AF: LASP, U.of Colorado, Boulder, CO 80309, United States
AU: Sternovsky, Z
EM: zoltan.sternovsky@colorado.edu
AF: LASP, U.of Colorado, Boulder, CO 80309, United States
AU: Robertson, S
EM: Scott.Robertson@colorado.edu
AF: Department of Physics, U.of Colorado, Boulder, CO 80309, United States
AU: Morfill, G E
EM: gem@mpe.mpg.de
AF: Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching, 85748, Germany
AB: Surfaces in space exposed to plasmas and UV radiation will become charged and develop a sheath region with an electric field normal to the surface. Typically, this electric field is on the order of a few V/m, too small to lift-off micron sized grains with an expected charge of a single electron on the lunar surface, for example. Much higher electric fields can be generated due to differential UV charging between neighboring lit and dark surface elements, a common situation during sunset or sunrise. The moving lit/dark boundary can also lead to an increased surface charge density, which in combination with the strong localized electric field could lead to the mobilization and transport of the lunar soil. Here we report on a series of ongoing experiments to investigate differential photoelectron charging, and the so- called 'super-charging' effect, related to the moving boundaries between illuminated and dark surfaces. We will also discuss new plasma diagnostic methods to characterize the spatial and energy distribution of electrons in the dilute plasma sheath formed by UV generated emission on the lunar surface.
DE: 5415 Erosion and weathering
DE: 5465 Rings and dust
DE: 6015 Dust
DE: 6250 Moon (1221)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting