Electron density measured during BepiColombo and Mariner 10 flybys. From top to bottom: electron density profiles for MFB1, MFB2, MFB3, and M10 FB1 displayed as a function of the distance along the Y_MSO axis. The vertical dashed green line delineates the CA. For each flyby, the spacecraft altitude (in Mercury radius) and the time (in UTC, HH:MM) are indicated below the corresponding plot. We note that the time increases from right to left. The red, green, and light and dark blue boxes below the corresponding plot delineate the SW, the magnetosheath, the magnetosphere, and the eclipse or shadow regions crossed by the spacecraft for each flyby, respectively. The blue stars and red crosses represent the densities deduced from the 3D and OMNI data products of MEA1, respectively.