The source of the Jupiter S-bursts

Abstract

The transient radio S-bursts from Jupiter are strongly correlated with the orbital position of the satellite Io for all wave frequencies between 8 MHz and 30 MHz, and with system III longitude above about 15 MHz. The observations are most easily explained if the electrons generating the S-bursts are confined to the planetary magnetic flux tube intersecting Io (the IFT)¹. The primary source of the electron energy is thought to be the electromotive force (EMF) generated by the relative motion of Io across the Jupiter magnetic field, the S-bursts being the result of convective instabilities in the consequent current flow in the IFT. The electrons are assumed to emit coherent electromagnetic radiation in the Doppler cyclotron mode as they travel up the IFT after being accelerated near its feet in the Jupiter ionosphere to energies of a few keV (refs 2–4).