Localized "Jets" of Jovian Electrons Observed during Ulysses' Distant Jupiter Flyby in 2003-2004

1. Localized "Jets" of Jovian Electrons Observed during Ulysses' Distant Jupiter Flyby in 2003-2004 • “Proto-type” jet observed in Dec 2003 Ulysses position: • 0.9 AU North of Jupiter • 1.7° separation in longitude and 0.09 AU in radius Jets (filled circles) observed at Ulysses during the distant fly-by. Locations are shown w.r.t. Jupiter in vertical (ΔZ) and radial (ΔR) direction, presented in projection. Jupiter’s magnetosphere (centred at the origin, shown in dark gray) is approx. to scale.

2. Implications of Jovian electron jet observations for charged particle propagation • Observation of an electron jet requires a direct magnetic connection between Jupiter’s magnetosphere and Ulysses • For the events observed in 2003-2004, this required large deviations from the average (Archimedean) spiral magnetic field direction • Existing models of systematic deviations from the average spiral pattern predict that radial distances of several AU are needed for a deviation of order 1 AU to develop. • Ulysses observations of jets show that such deviations occur within a radial interval of only ~0.1 AU. • If such large deviations are indeed common, they may play a significant role in transporting particles throughout the heliosphere by providing paths for particles to propagate parallel to the local field while crossing the average field. • It is not yet clear • how or why such large scale deviations develop, • whether they are consistently present throughout the solar cycle • how to incorporate them into models of particle propagation