IOS INTERACTION WITH THE PLASMA TORUS - GALILEO MAGNETOMETER REPORT

Galileo magnetometer data at 0.22-second resolution reveal a complex i nteraction between Io and the flowing plasma of the Io torus. The high ly structured magnetic field depression across the downstream wake, al though consistent with a magnetized Io, is modified by sources of curr ents within the plasma that introduce ambiguity into the interpretatio n of the signature. Highly monochromatic ion cyclotron waves appear to be correlated with the local neutral particle density. The power peak s in the range of molecular ion gyrofrequencies, suggesting that molec ules from Io can remain undissociated over a region of more than 15 Io radii around Io.