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Laboratory Measurements of Charging of Apollo 17 Lunar Dust Grains by Low Energy ElectronsIt is well recognized that the charging properties of individual micron/sub-micron size dust grains by various processes are expected to be substantially different from the currently available measurements made on bulk materials. Solar UV radiation and the solar wind plasma charge micron size dust grains on the lunar surface with virtually no atmosphere. The electrostatically charged dust grains are believed to be levitated and transported long distances over the lunar terminator from the day to the night side. The current models do not fully explain the lunar dust phenomena and laboratory measurements are needed to experimentally determine the charging properties of lunar dust grains. An experimental facility has been developed in the Dusty Plasma Laboratory at NASA Marshall Space Flight Center MSFC for investigating the charging properties of individual micron/sub-micron size positively or negatively charged dust grains by levitating them in an electrodynamic balance in simulated space environments. In this paper, we present laboratory measurements on charging of Apollo 17 individual lunar dust grains by low energy electron beams in the 5-100 eV energy range. The measurements are made by levitating Apollo 17 dust grains of 0.2 to 10 micrometer diameters, in an electrodynamic balance and exposing them to mono-energetic electron beams. The charging rates and the equilibrium potentials produced by direct electron impact and by secondary electron emission processes are discussed.
Document ID
20080013313
Document Type
Conference Paper
Authors
Abbas, Mian M. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Tankosic, Dragana (Alabama Univ. Huntsville, AL, United States)
Spann, James F. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Dube, Michael J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Gaskin, Jessica (NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 24, 2013
Publication Date
December 10, 2007
Subject Category
Lunar and Planetary Science and Exploration
Meeting Information
2007 Fall Meeting of the American Geophysical Union(San Francisco, CA)
Distribution Limits
Public
Copyright
Other