Concerning the Interaction between Magnetopause Erosion and Induction at Mercury

Abstract:

Mercury's weak internal dipole field is subject to an intense solar wind and thus only a small magnetospheric cavity is created. The location of the outer boundary, the magnetopause, is mainly controlled by a pressure balance between the solar wind pressure outside and magnetic pressure inside, but during times of intense dayside reconnection the stand-off distance may be reduced due to erosion. For the Hermean magnetosphere, different erosion mechanisms such as direct flux transport, neutral current sheet enhancement, field-aligned currents and interplanetary magnetic field penetration are compared. As any of these erosion mechanisms change the external field experienced by the planet, currents are induced within the electrically conductive planetary interior. Secondary magnetic fields from these induced currents counteract their source by temporarily increasing the planetary magnetic moment. We conclude with an estimate of the induced magnetic field range possible for various internal conductivity structures.