Example of a MESSENGER orbital observation of the magnetic properties around Mercury. (a, b) Magnetic field magnitude and its three components in the aberrated MSM coordinates. (c) Magnetic fluctuation and its compressional/transversal components. (d) Spectrogram of the ion differential energy flux (cm⁻² sr⁻¹ s⁻¹ keV⁻¹). The horizontal green, red, and blue bars label the solar wind (SW), magnetosheath (MSH), and magnetosphere (MSP) regions, respectively. (e) and (f) MESSENGER orbit projected onto the equatorial and noon-midnight planes relative to the Mercury surface (circle) and the average magnetopause (MP) and bow shock (BS) from the model (Zhong et al. 2015a).