Molecular Dynamics Simulations of Dielectric Breakdown of Lunar Regolith: Implications for Water Ice Formation on Lunar Surface.

Molecular dynamics simulations are carried out to investigate dielectric breakdown of lunar regolith induced by space weather events and its potential effects on water ice formation on lunar surface. We find that dielectric breakdown can trigger the water formation process by breaking the chemical bonds of regolith grains and exposing the oxygen atoms to react with the hydrogen implanted by solar wind. In the permanently shadowed region, the water molecules formed become attached to regolith grains in the molecular structure of ice after the event. Thus, dielectric breakdown can also enable the preservation of water molecules by changing the hydrophobicity of regolith grains. Plain Language Summary: This study considers dielectric breakdown of lunar regolith induced by space weather events and presents the first molecular dynamics simulation study of the breakdown process and the relevant chemical reactions. We find that dielectric breakdown is a triggering mechanism for water formation on lunar surface. Dielectric breakdown also changes the hydrophobicity of the regolith grains and, thus, enables the preservation of the water molecules formed in the grain. Key Points: We report the first MD simulations of chemical reactions during lunar regolith dielectric breakdownDielectric breakdown breaks the chemical bonds of lunar regolith and triggers water formationDielectric breakdown changes hydrophobicity of regolith and enables preservation of water molecules [ABSTRACT FROM AUTHOR]