On the Effect of Magnetospheric Shielding on the Lunar Hydrogen Cycle

The global distribution of surficial hydroxyl on the Moon is hypothesized to be derived from the implantation of solar wind protons. As the Moon traverses the geomagnetic tail, it is generally shielded from the solar wind; therefore, the concentration of hydrogen is expected to decrease during full Moon. A Monte Carlo approach is used to model the diffusion of implanted hydrogen atoms in the regolith as they form metastable bonds with O atoms, and the subsequent degassing of H-2 into the exosphere. We quantify the expected change in the surface OH and the H-2 exosphere using averaged SW proton flux obtained from the Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) measurements. At lunar local noon, there is a small difference

Automated summary

The global distribution of surficial hydroxyl on the Moon is hypothesized to be derived from the implantation of solar wind protons. A Monte Carlo approach is used to model the diffusion of implanted hydrogen atoms in the regolith as they form metastable bonds with O atoms. The expected decrease in hydrogen concentration during full Moon is quantified using averaged SW proton flux measurements from ARTEMIS.