The exospheric Na emission from ground-based observation as a tracer of solar wind precipitation at Mercury

Following previous studies from Orsini et al (2018), Mangano et al. (2015) and Massetti et al (2017), this presentation is based on the analysis of exospheric Na emission at Mercury as monitored during a long campaign of ground-based observations from THEMIS solar telescope in the Canary Islands, to investigate deeper the connection between the interplanetary magnetic field near Mercury and the morphology of the planetary Na exosphere. In particular, our work focuses on the possible relationship between the Na emission location at high latitudes on the day-side hemisphere of Mercury with the interplanetary magnetic field as measured in situ by the magnetometer onboard the MESSENGER spacecraft.Both Na exospheric emission and magnetic field data are averaged over the same time periods, i. e. approximately one hour for each detection. The results that will be discussed are based on about 100 events extracted from THEMIS database in similar seeing conditions, performed during the MESSENGER mission lifetime (2011-2012-2013).