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| Titel |
Photoemission from glass dust grains: First measurements |
| VerfasserIn |
Libor Nouzak, Radim Pechal, Jiri Pavlu, Jana Safrankova, Zdenek Nemecek |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087546
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| Publikation (Nr.) |
 EGU/EGU2014-1601.pdf |
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| Zusammenfassung |
| Dust grains are present in the interstellar space and also on surfaces of space objects like the
Moon. The grains are charged by photoemission caused by solar UV radiation and by charged
particles from the ambient plasma (solar wind, planetary magnetospheres). A balance of
different charging processes on both sunlit and night sides of the Moon causes interesting
phenomena as dust horizon glow, dust fountains, and dust levitation. To contribute to a better
understanding of these processes, we present laboratory investigations that use
a single SiO2 grain of micron size (an archetype of the lunar dust) caught in the
electrodynamic trap. We irradiate it by HeI (21.2eV) photons and electrons and
discuss a contribution of these two processes to the grain charge. The grain specific
charge is evaluated by an analysis of its motion and position in the trap. We compare
equilibrium charge-to-mass ratios given by the electron emissions induced by electrons
and by the UV photons from the HeI lamp. First measurements indicate that the
resulting charge is about twice larger for photoemission than that caused by an electron
impact. |
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