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| Titel |
Influence of solar wind ions on photoemission charging of dust |
| VerfasserIn |
Libor Nouzak, Ivana Richterova, Jiri Pavlu, Jana Safrankova, Zdenek Nemecek |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124508
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| Publikation (Nr.) |
 EGU/EGU2016-3954.pdf |
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| Zusammenfassung |
| The lunar surface covered by a layer of dust grains is exposed to solar wind particles and
photons coming from the Sun on the sunlit side. Solar wind ions cause sputtering of dust
grains or can be implanted into grains. We suppose that as a consequence of ion implantation,
an additional energy is transferred to grains, more valence band electrons are excited, and the
photoelectron yield is increased. An increase of the photoelectron current causes the
enhanced density of electrons that form a sheet above the illuminated lunar surface. Thus, an
influence of solar wind ions on the Debye length and photoelectron sheet formation is
expected.
We present laboratory estimations of work functions and photoelectron yields of a single
micron-sized silica grain before and after ion implantation. The silica grain used as a lunar
simulant is caught in the electrodynamic trap. Grain’s specific charge is evaluated by an
analysis of the grain motion within the trap, while its work function is determined from
observations of a time evolution of the charge-to-mass ratio when the grain is irradiated by
photons of different emission lines. By comparison of the photoelectron current (from
grain) with photon flux (from UV source), we establish the photoelectron yield of
the trapped object. The influence of ion implantation is thoroughly analyzed and
discussed. |
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