Whistler Wings and Reflected Particles During Solar Wind Interaction of Lunar Magnetic Anomalies

Abstract

AbstractThe solar wind interaction of small‐scale lunar magnetic anomalies remains unsolved due to lack of in situ observations. A dedicated coordinate system is established here to reconstruct the distributions of two remotely sensed symptoms of this interaction: the low‐frequency whistlers and reflected protons. It is found that these whistlers form a pair of wings beside the Moon and they originate from the low‐altitude interaction region, instead of from the higher altitudes where the reflected protons arrive and the associated shocks possibly form. Electrons and protons may behave differently in the interaction region. The incident electrons remain in a fluid state and may be diverted by the anomalies, exciting the low‐frequency whistlers. The protons, however, become unmagnetized and are reflected specularly by the vertical electric fields. These electric fields may derive from the charge separation/different motions of the electrons and protons, although the presence of low‐altitude shocks cannot be ruled out completely.