Rotationally driven quasi-periodic radio emissions in the Jovian magnetosphere

The occurrence characteristics of Jovian multiple quasi-periodic (QP) bursts are investigated based on Galileo spacecraft observations. Multiple QP bursts recurrently appeared in a group with a planetary spin period of 10 hours. Their appearance was synchronized with the planetary rotation, i.e., they were preferably excited when Jupiter had a particular spin phase angle with respect to the Sun (at a subsolar longitude of System III around 260-320 degrees). We also found that the burst groups were activated during magnetospheric disturbances probably caused by solar wind pressure variations. The rotationally driven polar disturbances accompanying quasi-periodic particle accelerations and radio wave bursts are discussed as being one of the daily unloading processes of planetary rotational energy.