The Relationship Between the Energization of Moon‐Originating Ions and Terrain Type on the Lunar Surface

We analyze data acquired by the Kaguya satellite on 14 October 2008 when the Moon was in the terrestrial magnetotail lobe to gain new insight into the energization of ions originating from the Moon. The Moon‐originating ions were detected over a broad range of latitudes from −80° to 50° above the Moon's dayside at ∼100 km altitude. The fluxes of the Moon‐originating ions were observed at energies from ∼50 to ∼1,000 eV. Additionally, these ions exhibited a wide distribution pitch angle spanning from ∼45 to 90°. The energy levels of ions originating from the Moon show rapid changes, either increasing or decreasing by a factor of ∼10 within 8 min without the solar zenith angle dependence. Such rapid energy changes were observed over the highland regions. These observations are discussed in light of possible acceleration mechanisms of Moon‐originating ions, including temporal and spatial effects. Key Points The Moon‐originating ions are distributed over a broad range of latitudes from −80° to 50° The median peak energy of Moon‐originating ions does not show a significant dependence on the solar zenith angle between 0° and 60° The energy of the Moon‐originating ions shows a sudden rise or drop by a factor of ∼10 in 8 min over the highland regions