Emission of energetic neutral atoms measured on the lunar surface by Chang'E-4. (15th September 2020)

• Record Type: Journal Article
• Authors: Zhang, Aibing; Wieser, Martin; Wang, Chi; Barabash, Stas; Wang, Wenjing; Wang, Xiaodong; Zou, Yongliao; Li, Lei; Cao, Jinbin; Kalla, Leif; Dai, Lei; Svensson, Johan; Kong, Linggao; Oja, Magnus; Liu, Bin; Alatalo, Vesa; Zhang, Yiteng; Talonen, Juha; Sun, Yueqiang; Emanuelsson, Magnus; Xue, Changbin; Wang, Lei; Wang, Fang; Liu, Wenlong
• Is Part Of: Planetary and space science. Volume 189(2020)
• Publication Date: 2020-09-15
• Subjects: ASAN -- Chang'E-4 -- ENA -- Energy spectrum -- Albedo; Space sciences -- Periodicals; Atmosphere, Upper -- Periodicals; Sciences spatiales -- Périodiques; Haute atmosphère -- Périodiques; 523
• DOI: 10.1016/j.pss.2020.104970
• Languages: English
• ISSNs: 0032-0633

Abstract

Abstract: The Advanced Small Analyzer for Neutrals (ASAN) is an international payload onboard the Chinese Chang'E-4 rover. It performed for the first time measurements of energetic neutral atoms (ENAs) on the lunar surface. We show a typical mass separated ENA energy spectrum measured by the ASAN. After normalizing to the impinging solar wind proton energy, good agreement to previous measurements from Chandrayaan-1 and IBEX is found. The hydrogen ENA albedo is estimated to be 32% for energy above 30 ​eV, comparable to the estimates obtained from Chandrayaan-1 and IBEX. Particle fluxes at lower energies are generally higher than those observed by Chandrayaan-1 and IBEX, and possible reasons are discussed. Highlights: First energetic neutral atom measurements directly on the lunar surface. Good agreement with remote observations at higher energies. Different from remote observations at lower energies.