Crossing of a magnetic reconnection diffusion region in the near-Mercury magnetotail by MESSENGER. The meridional (a) and equatorial (b) plane of the Mercury’s magnetosphere showing magnetic reconnection of the tail magnetic field lines (green curves). The blue lines show the trajectory of MESSENGER spacecraft through the current sheet crossing near the position of [−2.0, −0.5, −0.1] R_M in aberrated Mercury Solar-Magnetospheric (MSM) coordinates. The MSM system is centered on Mercury’s offset internal dipole with the X-axis oriented sunward along the Sun–Mercury line, the Z-axis parallel to the planetary spin axis and positive in the northward direction, and the Y-axis completes the right-handed system. An aberration of 6.8° due to Mercury’s instantaneous orbital speed through the radial solar wind speed of 400 km s⁻¹ is assumed. The displacement of the planetary center relative to the X–Z plane is because of the northward offset of the magnetic dipole by ∼0.2 R_M (Anderson et al. 2011). The dimensions of the magnetosphere in the two planes contain differences due to asymmetries in Mercury’s magnetopause geometry (Zhong et al. 2015a). The red arrows are the projections of the current sheet coordinate system (LMN) axes.