Comparative Magnetospheres in the Solar System

Abstract:

Magnetospheres created by planetary magnetic fields interacting with the solar wind have now been observed at Earth, Mercury, Jupiter, Saturn, Uranus, and Neptune; a sub-magnetosphere created by the internal magnetic field of Ganymede interacting with Jupiter's magnetosphere has been identified; and the entire heliosphere is sometimes described as a giant magnetosphere created by the solar wind and solar magnetic field interacting with the interstellar medium. Structures and dynamical processes in the Earth's magnetosphere can be better understood by comparing them to what found in other magnetospheres (and vice versa). Magnetic field line reconnection, coupling of the magnetosphere to solar wind flow and/or planetary rotation, with associated energy input and dissipation, and coupling of plasma flow to source regions (solar wind, ionosphere/atmosphere/surface, moons of the planet) are universal processes; they occur at all magnetospheres but can differ greatly both in spatial configuration and in temporal profile, depending on planetary, magnetospheric and solar wind parameters. I shall survey the various magnetospheres, with emphasis on similarities to and differences from magnetospheric dynamics at Earth and on implications for physics of the processes.