Modeling M-I Coupling at Jupiter and Saturn

Some aspects of M-I coupling are universal from one planet to another, for example, the crucial role played by Birkeland (magnetic-field-aligned) currents that dynamically couple the collisionless magnetosphere to the collisional ionosphere. This talk will focus on rotation-driven magnetospheres (e.g., Jupiter and Saturn) versus solar-wind-driven magnetospheres (e.g., Mercury and Earth). The magnetospheres of Jupiter and Saturn are driven by planetary rotation, through the agency of internal plasma sources delivered by moons internal to the magnetosphere, primarily Io at Jupiter and Enceladus at Saturn. I will review key observations, primarily from Saturn, which is the betterobserved example thanks to Cassini, and theoretical and numerical modeling efforts that attempt to explain these observations