Magnetic Holes in the Mercury Magnetosheath and Near Solar Wind.

Magnetic holes are deep, localized depression in the magnetic field strength, commonly observed in the solar wind. Recent observations have revealed that they are also present in Earth's magnetosheath and in the coma of comet 67/P. We here present a large statistical investigation of magnetic holes (here defined as a decrease of at least 50% from the background magnetic field strength) in the Mercury magnetosheath and near solar wind, using MESSENGER magnetometer data. We compare the properties of the magnetic holes observed in the two regions, and discuss whether the magnetic holes in the magnetosheath are likely to be created locally, or if they are solar wind magnetic holes that have convected across the bow shock. We also discuss the possible role of magnetic holes in the interaction of the solar wind and the Mercury magnetosphere, and how this could be studied by the newly launched BepiColombo mission.