Mechanism for the acceleration and ejection of dust grains from Jupiter's magnetosphere

The Ulysses mission detected quasi-periodic streams of high-velocity submicron-sized dust particles during its encounter with Jupiter. It is shown here how the dust events could result from the acceleration and subsequent ejection of small grains by Jupiter's magnetosphere. Dust grains entering the plasma environment of the magnetosphere become charged, with the result that their motion is then determined by both electromagnetic and gravitational forces. This process is modeled, and it is found that only those particles in a certain size range gain sufficient energy to escape the Jovian system. Moreover, if Io is assumed to be the source of the dust grains, its location in geographic and geomagnetic coordinates determines the exit direction of the escaping particles, providing a possible explanation for the observed periodicities. The calculated mass and velocity range of the escaping dust gains are consistent with the Ulysses findings.