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| Titel |
Electrons on closed field lines of lunar crustal fields in the solar wind wake |
| VerfasserIn |
Masaki N. Nishino, Yoshifumi Saito, Hideo Tsunakawa, Futoshi Takahashi, Masaki Fujimoto, Yuki Harada, Shoichiro Yokota, Masaki Matsushima, Hidetoshi Shibuya, Hisayoshi Shimizu |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102774
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| Publikation (Nr.) |
 EGU/EGU2015-2173.pdf |
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| Zusammenfassung |
| Plasma signature around crustal magnetic fields is one of the most important topics of the
lunar plasma sciences. Although recent spacecraft measurements are revealing solar-wind
interaction with the lunar crustal fields on the dayside, plasma signatures around crustal fields
on the night side have not been fully studied yet. Here we show evidence of plasma trapping
on the closed field lines of the lunar crustal fields in the solar-wind wake, using SELENE
(Kaguya) plasma and magnetic field data obtained at 14–15 km altitude from the lunar
surface. In contrast to expectation on plasma cavity formation at the strong crustal fields,
electron flux is enhanced above Crisium Antipode (CA) anomaly which is one of the
strongest lunar crustal fields. The enhanced electron fluxes above CA are characterised by (1)
occasional bi-directional field-aligned beams in the lower energy range (< 150 eV)
and (2) a medium energy component (150–300 eV) that has a double loss-cone
distribution representing bounce motion between the two footprints of the crustal
magnetic fields. The low-energy electrons on the closed field lines may come from
the lunar night side surface, while supply mechanism of medium-energy electrons
on the closed field line remains to be solved. We also report that a density cavity
in the wake is observed not above the strongest magnetic field but in its vicinity. |
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