Affiliation:
1. Space Sciences Laboratory University of California, Berkeley Berkeley CA USA
2. Department of Geophysics Kyoto University Kyoto Japan
3. Department of Physics and Astronomy University of Iowa Iowa City IA USA
4. Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA
Abstract
AbstractLunar surface charging is a scientifically and practically important topic at the Moon that is largely determined by the electron currents near the surface. Among those electron populations, lunar photoelectrons (PHE) and backscattered electrons (BSE) produced by incident electrons that make up the high‐energy tail of lunar emitted electrons are not well characterized yet. Recently, Xu et al. (2021, https://doi.org/10.1029/2020je006790) reported oxygen Auger electron observations at the Moon by the Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun spacecraft, which provides a unique feature to identify lunar photoelectrons. We utilize this feature to isolate cases of emitted electrons dominated by BSE over PHE. With selected BSE cases, we characterize how the backscattering coefficient η varies with primary electron energy, which decreases with increasing energy. Our results also reveal η to be dependent on the magnetic dip angle, as a fraction of BSE re‐impact the surface in a magnetized environment. The characterization of the backscattering coefficient not only gives insights into the lunar surface properties and lunar surface charging but could also be potentially applied to other airless bodies.
Funder
National Aeronautics and Space Administration
Publisher
American Geophysical Union (AGU)
Subject
Space and Planetary Science,Earth and Planetary Sciences (miscellaneous),Geochemistry and Petrology,Geophysics