A new view on the solar wind interaction with the Moon

Anil Bhardwaj,Yuki Harada,Mats Holmström,Charles Lue,Stas Barabash,Abhinaw Alok,Martin Wieser,Kazushi Asamura,M B Dhanya,Yoshifumi Futaana,Audrey Vorburger,Peter Wurz

doi:10.1186/s40562-015-0027-y

Abstract

Characterised by a surface bound exosphere and localised crustal magnetic fields, the Moon was considered as a passive object when solar wind interacts with it. However, the neutral particle and plasma measurements around the Moon by recent dedicated lunar missions, such as Chandrayaan-1, Kaguya, Chang'E-1, LRO, and ARTEMIS, as well as IBEX have revealed a variety of phenomena around the Moon which results from the interaction with solar wind, such as backscattering of solar wind protons as energetic neutral atoms (ENA) from lunar surface, sputtering of atoms from the lunar surface, formation of a "mini-magnetosphere" around lunar magnetic anomaly regions, as well as several plasma populations around the Moon, including solar wind protons scattered from the lunar surface, from the magnetic anomalies, pick-up ions, protons in lunar wake and more. This paper provides a review of these recent findings and presents the interaction of solar wind with the Moon in a new perspective.

Highlights

The Moon is a regolith covered planetary object characterised by a surface-bound exosphere (Killen and Ip 1999; Stern 1999; Sridharan et al 2010) and an absence of a global magnetic field
Observations from the recent missions, such as Chandrayaan-1, Kaguya, Chang’E-1, ARTEMIS, and IBEX have shown that the interaction of solar wind with the Moon is quite dynamic with a variety of processes involved, such as sputtering of lunar surface, scattering of 0.1–1 % solar wind protons with the same
The analysis showed that the energetic neutral atoms (ENA) albedo are sensitive to magnetic anomalies which causes the suppression of ENA intensity, whereas the other surface properties, e.g., changes in elevation of surface, chemical composition, and visible albedo do not play a significant role in the variation of ENA albedo

Summary

Introduction

The Moon is a regolith covered planetary object characterised by a surface-bound exosphere (Killen and Ip 1999; Stern 1999; Sridharan et al 2010) and an absence of a global magnetic field. Observations from the recent missions, such as Chandrayaan-1, Kaguya, Chang’E-1, ARTEMIS, and IBEX have shown that the interaction of solar wind with the Moon is quite dynamic with a variety of processes involved, such as sputtering of lunar surface, scattering of 0.1–1 % solar wind protons with the same

Results

Conclusion