Leakage of energetic particles from Jupiter's dusk magnetosphere: Dual spacecraft observations

For the first time, two spacecraft, Galileo and Cassini, observed Jupiter's magnetosphere simultaneously for nearly a half year between October 2000 and March 2001. This provided an unprecedented opportunity to disentangle spatial and temporal aspects of the dynamics of the Jovian magnetosphere. The dual spacecraft measurements show clearly that magnetospehre particles leak directly into the interplanetary medium from the closed magnetosphere, and are the source for the "upstream" particle events that have been reported from previous single Jupiter missions on Voyager and Ulysses.