Jovian <i>S</i> burst generation by Alfvén waves

Abstract

Jupiter's radio emissions are dominated in intensity by decametric radio emissions due to the Io‐Jupiter interaction. Previous analyses suggest that these emissions are cyclotron‐maser emissions in the flux tubes connecting Io or Io's wake to Jupiter. Electrons responsible for the emission are thought to be accelerated from Io to Jupiter. We present simulations of this hot electron population under the assumption of acceleration by Alfvén waves in the Io flux tube. Outside of limited acceleration regions where a parallel electric field associated with Alfvén waves exists, the electrons are supposed to have an adiabatic motion along the magnetic field lines. Near Jupiter a loss cone appears in the magnetically mirrored electron population, which is able to amplify extraordinary (X) mode radio waves. The X‐mode growth rate is computed, which allows us to build theoretical dynamic spectra of the resulting Jovian radio emissions, whose characteristics match those observed for Jovian S bursts.