Periodic acceleration mechanism for the Jovian magnetosphere

The discovery of radio emissions from Jupiter in the late 195's suggested that the planet possessed large numbers of high energy particles trapped within a planetary magnetic field that was in some ways similar to the Earth's. The Pioneer 1 and 11 missions confirmed that the Jovian magnetosphere does contain energetic protons and electrons. The two probes also discovered unexpected features of the Jovian magnetosphere such as its large radial extent and various 1-hour, spin-related periodicities. There are difficulties that any model of Jupiter's magnetosphere must overcome to explain the new data. Specifically, some powerful acceleration mechanism is required to supply energetic particles to the Jovian magnetosphere. Relying on ionospheric plasma periodically released into the Jovian magnetotail, I argue that centrifugal acceleration and magnetic field annihilation in the tail can periodically accelerate charged particles to very high energies in the outer magnetosphere. After this initial energization in the tail, the particles gain further energy by inward convections and diffusion. This mechanism qualitatively explains a number of the recent Pioneer findings and provides a plausible alternative to the so-called "magnetodisk" models sometimes used to interpret the Pioneer data