Effects of Absorption by lo on Composition of Energetic Heavy lons

The Galileo heavy ion counter is sensitive to ions with atomic numbers Z ≥ 6 and energies greater than ~6 MeV per nucleon. During Galileo's passage through Jupiter's inner magnetosphere, the observed composition of these heavy ions was consistent with the presence of singly ionized iogenic O, Na, and S and highly ionized solar C, O, and Ne. The solar component is absorbed more strongly by lo because its gyroradius is smaller than Io's diameter.