The charge state of electrostatically transported dust on regolith surfaces

The charge state of dust particles on regolith surfaces exposed to ultraviolet radiation or plasma is investigated for understanding the role of electrostatic dust transport in the surface evolution of airless planetary bodies. Our charge measurement shows that the regolith dust that can be electros...

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Veröffentlicht in:Geophysical research letters 2017-04, Vol.44 (7), p.3059-3065
Hauptverfasser: Schwan, J., Wang, X., Hsu, H.‐W., Grün, E., Horányi, M.
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Sprache:eng
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Zusammenfassung:The charge state of dust particles on regolith surfaces exposed to ultraviolet radiation or plasma is investigated for understanding the role of electrostatic dust transport in the surface evolution of airless planetary bodies. Our charge measurement shows that the regolith dust that can be electrostatically transported or lofted carries large negative charges. This result is consistent with our “patched charge model,” which predicts that dust particles forming microcavities in the regolith surfaces can attain large negative charges by collecting photoelectrons and/or secondary electrons emitted from neighboring particles and the resulting repulsive forces between these negatively charged particles lead to their mobilization. The observed negative charge polarity is contrary to the generally expected positive charges on the regolith dust emitting photoelectrons. The measured negative charges are orders of magnitude larger than the prediction by classical charging models. Our laboratory measurements provide critical initial charging conditions for regolith dust dynamics studies. Key Points Regolith dust that can be electrostatically transported carries unusually large negative charges The observed negative charge polarity is contrary to the generally expected positive charges on regolith dust emitting photoelectrons It provides critical initial charge state for dust dynamics studies to understand the surface evolution of airless bodies
ISSN:0094-8276
1944-8007
DOI:10.1002/2017GL072909