Interpretation of the observed changes in Jupiterʹs synchrotron radiation during and after the impacts from comet Shoemaker-Levy 9

The effects of the Shoemaker-Levy 9 collision with Jupiter included an abrupt and impulsive disturbance to Jupiterʹs inner magnetosphere. A substantial change to the radio emission originating from Jupiterʹs radiation belts (synchrotron radiation) was reported and confirmed by numerous observers. The major effect on the radiation belts is due to the latitude of the impact sites on Jupiter. The impacts occurred at the footprint of the magnetic field lines connecting Jupiterʹs inner radiation belts with the planet. Interferometric maps suggest changes may have continued for weeks after the impacts. The reported increases in synchrotron emission indicate substantial changes to the high energy electron population trapped in Jupiterʹs radiation belts. A number of mechanisms were suggested almost immediately to explain the observed changes: (1) enhanced radial diffusion, (2) shock acceleration and energization of the electron population and (3) pitch angle scattering of the emitting electrons from plasma waves triggered by the comet impacts. A review of the interpretation of the radio data and a discussion of the consistency between the proposed mechanisms and the observations is presented. A complete understanding of the state of the radiation belts before, during and after the impacts has not yet been reached and requires extensive modeling.