[P-PS04] Mercury Science and Exploration

[PPS04-P02] The dependence of Mercury’s magnetotail protons on IMF directions: MESSENGER observations

*毛利 智紀¹、原田 裕己¹、相澤 紗絵² (1.京都大学理学研究科、2.Laboratoire de Physique des Plasmas, CNRS)

キーワード：水星

Mercury has a small magnetosphere owing to its weak intrinsic magnetic field and interactions with the solar wind. A recent study has reported that proton number density sometimes shows a clear north–south asymmetry, which can be explained by solar wind proton entry along upstream-connected magnetic field lines. However, a full picture of the transport process of ions from the solar wind into Mercury’s magnetotail remains unclear. In this study, we use MESSENGER observations of magnetotail protons and interplanetary magnetic field (IMF) directions, thereby analyzing the dependence of spatial distributions of magnetotail protons on the IMF directions and proton energy. We identified that the magnetotail proton distributions for different energies show different dependences on the IMF directions. Based on these results, we discuss the transport process of ions from the solar wind into Mercury’s magnetotail.