资源环境科技发展态势分析平台

The Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS) mission observes anomalously low lunar nightside surface potentials while in the terrestrial magnetotail lobes. Observed potential magnitudes are between 15-40% that expected from ambient tail-plasma charging, are highly concentrated on the lunar dawn hemisphere, and are correlated with low ambient plasma densities. These characteristics suggest an additional, highly asymmetric source of cold current to the lunar surface. Given these characteristics, we identify micrometeoroid impact-generated plasmas as the likely source of this additional current. Using laboratory measurements of impact charge yields and models of the micrometeoroid flux to the Moon constrained by in-situ measurements, we show that currents due to micrometeoroid impact plasmas have the necessary magnitude and spatial distribution to explain the observed surface potential measurements. Micrometeoroid impact-generated currents may contribute to surface charging at airless bodies with intense micrometeoroid bombardment and/or low ambient plasma densities.