ENHANCED WHISTLER-MODE EMISSIONS - SIGNATURES OF INTERCHANGE MOTION IN THE IO TORUS

During the Galileo inbound pass through the Io torus the plasma wave i nstrument detected intervals of enhanced whistler-mode emissions. Over two of these intervals in the inner torus (L < 6.5), for which energe tic particle data is also available, the flux and pitch angle anisotro py of resonant electrons exhibited a simultaneous enhancement consiste nt with inward adiabatic transport from a source region in the outer t orus. The enhanced electromagnetic emissions are interpreted as a modu lation of cyclotron whistler-mode instability above the normal margina lly stable state of the plasma. This suggests that the enhanced emissi ons are a sensitive indicator of rapid inward transport associated wit h interchange motions in the Io torus.