Enhanced whistler‐mode emissions: Signatures of interchange motion in the Io torus

During the Galileo inbound pass through the Io torus the plasma wave instrument detected intervals of enhanced whistler‐mode emissions. Over two of these intervals in the inner torus ( L < 6.5), for which energetic particle data is also available, the flux and pitch angle anisotropy of resonant electrons exhibited a simultaneous enhancement consistent with inward adiabatic transport from a source region in the outer torus. The enhanced electromagnetic emissions are interpreted as a modulation of cyclotron whistler‐mode instability above the normal marginally stable state of the plasma. This suggests that the enhanced emissions are a sensitive indicator of rapid inward transport associated with interchange motions in the Io torus.