The Physics and Chemistry of Sputtering by Energetic Plasma Ions

Energetic ions from the solar wind, local pick-up ions or magnetospheric plasma ions impact the atmospheres and surfaces of a number of solar system bodies. These energetic incident ions deposit energy in the gas or solid. This can lead to the ejection of atoms and molecules, a process referred to as sputtering. In this paper we first describe the physics and chemistry of atmospheric and surface sputtering. We then apply this to the production of a thin atmosphere on Europa by magnetospheric ion bombardment of Europa’s surface and show that Europa loses more Na atoms than it receives from the Jupiter magnetosphere. The loss of atmosphere from Mars in earlier epochs by pick-up ion sputtering of that atmosphere is also calculated.