Expectations of BepiColombo MMO: Space plasma physics of the Hermean magnetosphere

Abstract:

Little had been known about the Hermean magnetosphere until MESSENGER explored the region. The region is formed as the weak planetary magnetic field stands against the intense solar wind in the close proximity of the Sun. Various prediction had been given by noting the difference in the parameters from the well-studied terrestiral magnetosphere of a similar setting and scaling the well-knowns to the Hermean environment. MESSENGER results, however, show a wide varieity of phenomena that are out of the scope of what one could have reasonably argued. The micro-magnetosphere of Mercury is much more dynamic than one had predicted. BepiColombo MMO, the JAXA spacecraft of the BepiColombo Mercury exploration mission, is equipped to study the space environment of the planet Mercury. Being a spinning spacecraft, BepiColombo MMO has much less constraint for plasma observations and is expected to extract essential elements of space plasma physics that become visible in the Hermean environment. Here we review MESSENGER results and how MMO will contribute to deepen our understanding of space plasmas by addressing the puzzles raised by MESSEGNER.