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Earth Planets Space, Vol. 60 (No. 4), pp. 375-385, 2008

Low-energy charged particle measurement by MAP-PACE onboard SELENE

Yoshifumi Saito1, Shoichiro Yokota1, Kazushi Asamura1, Takaaki Tanaka1, Ryota Akiba2, Masaki Fujimoto1, Hiroshi Hasegawa1, Hajime Hayakawa1, Masafumi Hirahara3, Masahiro Hoshino3, Shinobu Machida4, Toshifumi Mukai1, Tsugunobu Nagai5, Tsutomu Nagatsuma6, Masato Nakamura1, Koh-ichiro Oyama1, Eiichi Sagawaa7, Susumu Sasaki1, Kanako Seki8, and Toshio Terasawa5

1Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan
2Hamagin Research Institute, Ltd., 3-1-1 Minatomirai, Nishi-ku, Yokohama, Kanagawa 220-8616, Japan
3University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
4Kyoto University, Oiwake-machi, Sakyo-ku, Kyoto 606-8502, Japan
5Tokyo Institute of Technology, I2-5, 2-12-1 Ookayama, Meguro, Tokyo 152-8551, Japan
6National Institute of Information and Communications Technology, 4-2-1 Nukuikitamachi, Koganei, Tokyo 184-8795, Japan
7Research Institute of Telecommunications and Economics, 3-22-1 Toranomon, Minato-ku, Tokyo 105-0001, Japan
8Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13 Honohara, Toyokawa, Aichi 442-8507, Japan

(Received March 20, 2007; Revised October 8, 2007; Accepted November 8, 2007; Online published April 9, 2008)

Abstract: MAP-PACE (MAgnetic field and Plasma experiment-Plasma energy Angle and Composition Experiment) is one of the scientific instruments onboard the SELENE (SELenological and ENgineering Explorer) satellite. PACE consists of four sensors: ESA (Electron Spectrum Analyzer)-S1, ESA-S2, IMA (Ion Mass Analyzer), and IEA (Ion Energy Analyzer). ESA-S1 and S2 measure the distribution function of low-energy electrons below 15 keV, while IMA and IEA measure the distribution function of low energy ions below 28 keV/q. Each sensor has a hemispherical field of view. Since SELENE is a three-axis stabilized spacecraft, a pair of electron sensors (ESA-S1 and S2) and a pair of ion sensors (IMA and IEA) are necessary for obtaining a three-dimensional distribution function of electrons and ions. The scientific objectives of PACE are (1) to measure the ions sputtered from the lunar surface and the lunar atmosphere, (2) to measure the magnetic anomaly on the lunar surface using two ESAs and a magnetometer onboard SELENE simultaneously as an electron reflectometer, (3) to resolve the Moon-solar wind interaction, (4) to resolve the Moon-Earth's magnetosphere interaction, and (5) to observe the Earth's magnetotail.
Key words: Moon, plasma, magnetic anomaly, alkali atmosphere, magnetosphere, solar wind.


Corresponding author E-mail: saito@stp.isas.jaxa.jp


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