Electrostatic Waves and Electron Heating Observed over Lunar Crustal Magnetic Anomalies

TL;DR

This study analyzes ARTEMIS spacecraft data to investigate electrostatic waves and electron heating phenomena over lunar magnetic anomalies, highlighting the roles of specific plasma instabilities in these processes.

Contribution

It identifies the key plasma instabilities responsible for electrostatic waves and electron heating over lunar magnetic anomalies based on spacecraft observations.

Findings

Electron two-stream instability (ETSI) and electron cyclotron drift instability (ECDI) drive electrostatic waves.

ECDI and modified two-stream instability (MTSI) contribute to electron heating.

Significant electron heating observed over lunar magnetic anomalies.

Abstract

Above lunar crustal magnetic anomalies, large fractions of solar wind electrons and ions can be scattered and stream back towards the solar wind flow, leading to a number of interesting effects such as electrostatic instabilities and waves. These electrostatic structures can also interact with the background plasma, resulting in electron heating and scattering. We study the electrostatic waves and electron heating observed over the lunar magnetic anomalies by analyzing data from the Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) spacecraft. Based on the analysis of two lunar flybys in 2011 and 2013, we find that the electron two-stream instability (ETSI) and electron cyclotron drift instability (ECDI) may play an important role in driving the electrostatic waves. We also find that ECDI, along with the modified two-stream instability (MTSI), may provide the mechanisms responsible for substantial isotropic electron heating over the lunar magnetic anomalies.