Jupiter Science Results - Plasma Composition

The Ulysses solar wind ion composition (SWICS) experiment has provided important new data on the composition of the magnetospheric plasma, in particular information on the charge states of the various ions (Fig.6). These measurements give new insights into the sources and "life history" of the Jovian plasma. Material from three sources, the solar wind, the planet itself and the volcanic satellite Io (Iogenic ions) can be traced by observing ions specific to each source. Large-scale mixing was observed to occur, with significant numbers of solar wind and Iogenic ions being found in all regions investigated. The implication is that solar wind plasma penetrates deep into the magnetosphere and Iogenic ions travel outwards to its outer reaches, both at low and high latitudes. These results provide important tests for models of plasma circulation, transport and loss from the magnetosphere.

Figure 6: SWICS ion composition data plotted in the form of a mass vs. mass-per-charge matrix of solar wind (top) and Jupiter magnetospheric plasma (bottom). The change in charge state and elemental composition is striking.