Chandrayaan-1 observations of backscattered solar wind protons from the lunar regolith: Dependence on the solar wind speed
2014 (English)In: Journal of Geophysical Research - Planets, ISSN 2169-9097, E-ISSN 2169-9100, Vol. 119, no 5, 968-975 p.Article in journal (Refereed) Published
We study the backscattering of solar wind protons from the lunar regolith using the Solar Wind Monitor of the Sub-keV Atom Reflecting Analyzer on Chandrayaan-1. Our study focuses on the component of the backscattered particles that leaves the regolith with a positive charge. We find that the fraction of the incident solar wind protons that backscatter as protons, i.e., the proton-backscattering efficiency, has an exponential dependence on the solar wind speed that varies from similar to 0.01% to similar to 1% for solar wind speeds of 250km/s to 550km/s. We also study the speed distribution of the backscattered protons in the fast (similar to 550km/s) solar wind case and find both a peak speed at similar to 80% of the solar wind speed and a spread of similar to 85km/s. The observed flux variations and speed distribution of the backscattered protons can be explained by a speed-dependent charge state of the backscattered particles.
Place, publisher, year, edition, pages
2014. Vol. 119, no 5, 968-975 p.
Moon, proton, backscatter, regolith
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:umu:diva-91225DOI: 10.1002/2013JE004582ISI: 000337693900004OAI: oai:DiVA.org:umu-91225DiVA: diva2:734802