Solar wind charge exchange observed through the lunar exosphere

Abstract

[1] X-rays can be generated by charge exchange between highly-charged heavy solar wind ions and neutrals. Previously, simulations have only been performed for X-ray emission due to solar wind charge exchange (SWCX) with geocoronal and interstellar neutrals. However, X-rays can also be generated by SWCX with the Moon's tenuous exosphere, which should be detectable by an imaging X-ray instrument located on the Moon. In addition, lunar-based observations of X-ray emission originating from Earth's magnetosheath will be able to provide information on the dynamic response of the bow shock and magnetopause to solar wind variations. Furthermore, X-ray emissions from SWCX within the heliosphere constitute part of the soft X-ray background (SXRB) emission, competing with emissions originating from outside the solar system. Lunar observations of soft X-rays will give additional information about these charge exchange processes and be critical in removing the heliospheric component of the SXRB.