,- Swedish Institute of Space Physics, SSPT, Kiruna, Sweden (wieser@irf.se)
Solar wind protons precipitating onto the lunar regolith result in backscattering and sputtering of surface atoms. Emitted particles are a source for the lunar exosphere. The interaction between precipitating solar wind and the surface does not conserve the charge state, thus positive [1] and negative [2] ions as well as energetic neutral atoms are emitted[3]. We combine data from recent measurements on the lunar surface by the NILS instrument[4] on Chang’e-6 and the ASAN instrument[5] on Chang’e-4, with data measured from orbit by Artemis[6] and Chandrayaan-1 [7] to investigate the full charge state distribution of emitted hydrogen. We discuss the fate of the different observed particle populations and their effect on in the near lunar environment.
[1] Saito, Y., et al., (2008). Solar wind proton reflection at the lunar surface: Low energy ion measurement by MAP-PACE onboard SELENE (KAGUYA). Geophys. Res. Lett., doi:10.1029/2008GL036077.
[2] Wieser, M., et. al, (2025). Direct observations of negative ions on the Lunar surface by Chang’E-6. Communications Earth & Environment, doi: 10.1038/s43247-025-02399-7.
[3] Wieser, M., et al.,(2009). Extremely high reflection of solar wind protons as neutral hydro- gen atoms from regolith in space. Planetary and Space Science. doi: 10.1016/j.pss.2009.09.012.
[4] R. Canu-Blot, et al. (2025), The Negative Ions at the Lunar Surface (NILS) Instrument on the Chang’E-6 Mission. Space Science Reviews, doi:10.1007/s11214-025-01162-w
[5] M. Wieser, et al. (2020), The Advanced Small Analyzer for Neutrals (ASAN) on the Chang’E-4 Rover Yutu-2. Space Science Reviews, doi:10.1007/s11214-020-00691-w
[6] C. Lue, et al.,(2018), Artemis observations of solar wind proton scattering off the lunar surface. Journal of Geophysical Research: Space Physics, doi:10.1029/2018JA025486
[7] Barabash, S., et al., (2009). Investigation of the solar wind–Moon interaction onboard Chandrayaan-1 mission with the SARA experiment. Current Science, 96(4):526–532.
How to cite: Wieser, M., Canu-Blot, R., Barabash, S., and Stenberg Wieser, G.: Backscattered and sputtered atoms and ions in the near surface environment of the Moon, Europlanet Science Congress 2026, The Hague, The Netherlands, 7–11 Sep 2026, EPSC2026-969, https://doi.org/10.5194/epsc2026-969, 2026.
