The longitudinal asymmetry of the Io plasma torus, as predicted by the magnetic-anomaly model and observed by Earth-based optical astronomy, provides a driving mechanism for a corotating convection system in Jupiter's magnetosphere. Here we deduce some qualitative properties of this convection system from the general equations that govern a steady state corotating convection system (although we expect that time-dependent effects may also have to be included for a complete description of Jovian convection). The corotating convection system appears capable of providing both the dominant radial transport mechanism (with a time scale possibly as short as a few rotation periods) and the dominant mechanism for extracting energy from Jupiter's rotation (at a rate ~1015 W) for driving a wide variety of magnetospheric phenomena. A similar corotating convection system may occur in other rotation-dominated magnetospheres, for example, those of pulsars and Saturn.