In-flight performance and initial results of plasma energy angle and composition experiment (PACE) on SELENE (Kaguya)

Yoshifumi Saito, Shoichiro Yokota, Kazushi Asamura, Takaaki Tanaka, Masaki N. Nishino, Tadateru Yamamoto, Yuta Terakawa, Masaki Fujimoto, Hiroshi Hasegawa, Hajime Hayakawa, Masafumi Hirahara, Masahiro Hoshino, Shinobu MacHida, Toshifumi Mukai, Tsugunobu Nagai, Tsutomu Nagatsuma, Tomoko Nakagawa, Masato Nakamura, Oyama Koichiro, Eiichi SagawaSusumu Sasaki, Kanako Seki, Iku Shinohara, Toshio Terasawa, Hideo Tsunakawa, Hidetoshi Shibuya, Masaki Matsushima, Hisayoshi Shimizu, Futoshi Takahashi

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

MAP-PACE (MAgnetic field and Plasma experiment-Plasma energy Angle and Composition Experiment) on SELENE (Kaguya) has completed its ∼1.5-year observation of low-energy charged particles around the Moon. MAP-PACE consists of 4 sensors: ESA (Electron Spectrum Analyzer)-S1, ESA-S2, IMA (Ion Mass Analyzer), and IEA (Ion Energy Analyzer). ESA-S1 and S2 measured the distribution function of low-energy electrons in the energy range 6 eV-9 keV and 9 eV-16 keV, respectively. IMA and IEA measured the distribution function of low-energy ions in the energy ranges 7 eV/q-28 keV/q and 7 eV/q-29 keV/q. All the sensors performed quite well as expected from the laboratory experiment carried out before launch. Since each sensor has a hemispherical field of view, two electron sensors and two ion sensors installed on the spacecraft panels opposite each other could cover the full 3-dimensional phase space of low-energy electrons and ions. One of the ion sensors IMA is an energy mass spectrometer. IMA measured mass-specific ion energy spectra that have never before been obtained at a 100 km altitude polar orbit around the Moon. The newly observed data show characteristic ion populations around the Moon. Besides the solar wind, MAP-PACE-IMA found four clearly distinguishable ion populations on the dayside of the Moon: (1) Solar wind protons backscattered at the lunar surface, (2) Solar wind protons reflected by magnetic anomalies on the lunar surface, (3) Reflected/backscattered protons picked-up by the solar wind, and (4) Ions originating from the lunar surface/lunar exosphere.

Original languageEnglish
Pages (from-to)265-303
Number of pages39
JournalSpace Science Reviews
Volume154
Issue number1-4
DOIs
Publication statusPublished - 2010 Jul 1

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Saito, Y., Yokota, S., Asamura, K., Tanaka, T., Nishino, M. N., Yamamoto, T., Terakawa, Y., Fujimoto, M., Hasegawa, H., Hayakawa, H., Hirahara, M., Hoshino, M., MacHida, S., Mukai, T., Nagai, T., Nagatsuma, T., Nakagawa, T., Nakamura, M., Koichiro, O., ... Takahashi, F. (2010). In-flight performance and initial results of plasma energy angle and composition experiment (PACE) on SELENE (Kaguya). Space Science Reviews, 154(1-4), 265-303. https://doi.org/10.1007/s11214-010-9647-x