[P-EM06] Magnetospheric Multi-Scale (MMS) mission -- A new age of magnetospheric physics

[PEM06-10] Locations of Magnetopause Magnetic Reconnection: The Role of Magnetosheath Plasma Pressure

*Hui Zhang¹, Zuyin Pu², Jianyong Lu³, Suiyan Fu², Changbo Zhu¹, Chongjing Yuan¹, Zhaodi Zhou¹, Weixing Wan¹, Libo Liu¹, Yiding Chen¹, Huijun Le¹ (1.Institute of Geology and Geophysics, Chinese Academy of Sciences, 2.School of Earth and Space Sciences, Peking University, 3.College of Math & Statistics, Institute of Space Weather, Nanjing University of Information Science and Technology)

Keywords:Magnetopuse, Magnetic Reconnection, Pressure

Question of where magnetic reconnection (MR) occurs or equivalently what mechanisms control the initiation of MR on the dayside magnetopause is intensively studied but not fully understood. Here, a novel statistic study reveals that magnetosheath thermal pressure maximizes near the subsolar point, its location, however, is modified by the dipole tilt angle in a manner the same as MR locations are. The maximum sheath thermal pressure, cooccurring with the enhanced magnetic pressure immediately inside the magnetopause, is though to be linked to a maximum magnetopause current density, where tearing mode instabilities tend to develop and MR initiates. The high pressure region shifts from the subsolar region due to magnetopause reshaping when the dipole tilt angle varies. The sheath flow stagnation point, however, remains unchanged at the subsolar point, and Xlines thus are embedded within sub Alfvenic sheath flows and are convected toward high latitudes. The successive Xlines may thus generate flux ropes.