In this work we investigate the effects of different interplanetary conditions on the near-Mercury's dynamics by means of hybrid simulations. In fact, along its orbit Mercury experiences significantly different environments in terms of interplanetary magnetic field (IMF) intensity and direction, as well as solar wind density and velocity.
 
In particular, we show the variations occurring in the bow-shock / magnetosheath / magnetopause system under a Parker's spiral IMF configuration as the orbit passes from the Aphelion position at 0.47 AU to the Perihelion position at 0.30 AU, as well as the effects of solar winds at different velocities. We observe these boundaries being significantly compressed towards the planetary surface as result of the interaction with high dynamic pressure and/or high Alfenic Mach number conditions. Moreover, a quasi-radial IMF configuration leads to the formation of an intense foreshock region concurring to further affect the boundaries characteristics.

Finally, one of the main consequences of such a variable near-planet magnetic dynamics is the different rate, intensity and energy distribution of the interplanetary particles capable of precipitating onto the planetary surface. These particles are thought to be one of the main source of the neutrals seen in the exosphere. We observe that the precipitation mainly occurs along the open-lines magnetic cusps regions. Unlike what found from some past simulations, these regions show a significant longitudinal displacement from the north-south meridian line probably due to the quasi-radial configuration, as well as a latitudinal displacement towards the equatorial plane as the incoming solar wind compression increases. Additionally, the presence of a compressed magnetosphere / bow-shock scenario concurs to increase the precipitation rate in the equatorial regions.