![Hier klicken, um den Treffer aus der Auswahl zu entfernen](images/unchecked.gif) |
Titel |
Type-II entry of solar wind protons into the lunar wake: Effects of magnetic connection to the night-side surface |
VerfasserIn |
Masaki N. Nishino, Masaki Fujimoto, Yoshifumi Saito, Hideo Tsunakawa, Yoshiya Kasahara, Mariko Kawamura, Masaki Matsushima, Futoshi Takahashi, Hidetoshi Shibuya, Hisayoshi Shimizu, Yoshitaka Goto, Kozo Hashimoto, Yoshiharu Omura, Atsushi Kumamoto, Takayuki Ono, Shoichiro Yokota |
Konferenz |
EGU General Assembly 2014
|
Medientyp |
Artikel
|
Sprache |
Englisch
|
Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 16 (2014) |
Datensatznummer |
250095587
|
Publikation (Nr.) |
EGU/EGU2014-11048.pdf |
|
|
|
Zusammenfassung |
Our recent observations around the Moon revealed that so-called type-II (T2) entry of the
solar wind protons into the near-Moon wake occurs when the IMF is dominated by the
non-radial components (i.e. BY and/or BZ). Under this condition a part of the solar wind
protons scattered/reflected at the lunar dayside surface subsequently enters the central region
of the near-Moon wake after a large-scale cycloid motion, which accelerates electrons
along the filed line into the wake. The situation handled in the previous studies is
that the relevant magnetic field line is detached from the lunar surface, leaving a
possibility of the T2 entry under magnetic connection left open. Here we report that
the protons can access the central wake region that is magnetically connected to
the lunar nightside surface, which we categorize into the T2 entry with magnetic
connection to the lunar surface (T2MC). Furthermore we show that the energy of the
electron beams induced by the proton entry into the wake depends on the magnetic
connectivity. Strong electron acceleration (up to several hundred eV to 1 keV) along the
magnetic field associated with the T2 entry is prominent when the field line has its
both ends in the solar wind, that is, when the magnetic field is detached from the
lunar surface (i.e. the previously-reported T2 entry that we rename to T2MD). On
the other hand, no significant electron acceleration is found in the T2MC cases,
although an enhancement of the electron flux associated with the T2 proton entry
is evident. We also report that the T2 entry process takes place even under radial
(BX-dominated) IMF condition. Our results indicate that, while the T2 entry of
solar wind protons into the wake itself does not require a special IMF condition but
is a rather general phenomenon, the characteristic energy of associated electrons
does show a strong dependence on the magnetic connectivity to the lunar surface. |
|
|
|
|
|