Sputtering yields of lunar soils under solar wind ion impact

Abstract

The Sun is the source of a multitude of processes that affect the surfaces of rocky objects and planets in the solar system. Besides thermal and electromagnetic irradiation, the solar wind is a plasma stream of mostly H + and He 2+ ions that predominantly interact with objects lacking a protective atmosphere or magnetic field. The impacts of these ions lead to surface sputtering, the liberation of material on a mostly atomic level, and thus contributes to the formation of a tenuous gas envelope called exosphere [1]. The exosphere’s properties are tightly linked to both the surface properties and the release mechanism. The exosphere therefore provides an opportunity to study the relevant object without the need for a lander, either by optical spectroscopy from or by mass spectroscopy during flybys or in orbit. The former has been achieved, e.g., for Mercury by the MESSENGER mission [2] while more recently, ESA’s BepiColombo mission to Mercury and NASA’s Artemis program for exploration of the Moon are expected to perform new in-situ studies soon.