Role of dispersive Alfven waves in generating parallel electric fields along the Io-Jupiter fluxtube

Alfvenic disturbances originating from Io are believed to accelerate electrons to energies of 10s of keV. The precipitation of these electrons generates the Io auroral footprint. The electric fields necessary for acceleration come from considering the inertial and kinetic corrections to the ideal Alfven wave. In this study, we examine where along the Io-Jupiter magnetic fluxtube these parallel electric fields can contribute to acceleration. Theoretical calculations show that dispersive Alfven electric fields within the torus are 2 orders of magnitude smaller than the electric fields which can be sustained at high latitudes along the fluxtube. This indicates that acceleration is caused by Alfvenic disturbances passing through the low-density plasma outside the torus with the strongest acceleration possible at 0.5 R-J above Jupiter.