Variation of the Moon’s Solar-Induced Hydrogen Cycle during a Solar Storm
- 1Howard University, Washington, D. C. USA
- 2NASA Goddard Space Flight Center, Greenbelt MD, USA
Observations of surficial OH/H2O in regolith grains on the Moon’s surface indicate variability on diurnal timescales 1–3 consistent with the variability of the solar wind proton flux and local surface temperature. Recent Monte Carlo models accounting for hydrogen diffusion and the degassed H2 exosphere support the theory of solar wind implantation being the primary driver of the lunar hydrogen cycle 4. In this presentation, we will report modeling results of the dynamical response of surficial OH content and the H2 exosphere during a Coronal Mass Ejection event, for which the proton flux can be a factor of 20 larger than nominal solar wind conditions 5,6. Observations of the response of hydrogen in the lunar environment during a solar storm event would provide strong support for solar wind implantation being the principal mechanism producing surface OH content and H2 exosphere.
Acknowledgment: Financial support from LEADER (NASA Award# 80NSSC20M0019) is gratefully acknowledged.
1. Li, S. et al. New formation processes of lunar surface water in Earth’s magnetotail. Nat Astron Accepted, (2023).
2. Li, S. & Milliken, R. E. Water on the surface of the Moon as seen by the Moon Mineralogy Mapper: Distribution, abundance, and origins. Sci Adv 3, 1–12 (2017).
3. Grumpe, A., Wöhler, C., Berezhnoy, A. A. & Shevchenko, V. v. Time-of-day-dependent behavior of surficial lunar hydroxyl/water: Observations and modeling. Icarus 321, 486–507 (2019).
4. Tucker, O. J., Farrell, W. M. & Poppe, A. R. On the Effect of Magnetospheric Shielding on the Lunar Hydrogen Cycle. J Geophys Res Planets 126, (2021).
5. Killen, R. M., Hurley, D. M. & Farrell, W. M. The effect on the lunar exosphere of a coronal mass ejection passage. Journal of Geophysical Research E: Planets 117, 1–15 (2012).
6. Farrell, W. M. et al. Solar-Storm/Lunar Atmosphere Model (SSLAM): An overview of the effort and description of the driving storm environment. J Geophys Res Planets 117, (2012).
How to cite: Misra, P., White, K., Farrell, W. M., and Tucker, O. J.: Variation of the Moon’s Solar-Induced Hydrogen Cycle during a Solar Storm, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17142, https://doi.org/10.5194/egusphere-egu23-17142, 2023.
