Remote sensing of mercury sodium exospheric patterns in relation to particle precipitation and interplanetary magnetic field.

The ground-based solar telescope THEMIS performed several observations of Mercury's sodium exosphere in years 2011-2013, when the MESSENGER spacecraft was orbiting around the planet. Typical two-peak exospheric patterns were frequently identified. In previous studies, some specific cases of THEMIS Na two-peak observations were characterized and related to IMF conditions, during specific extreme cases, in the occasion of CME arrival.