Statistical study of Saturn electrostatic discharges


  • P. Zarka,

  • B. M. Pedersen


During the Voyager Saturn mission the Planetary Radio Astronomy (PRA) experiment observed sporadic broadband emissions (20 KHz to at least 40 MHz) during a few days around the Voyager 1 and 2 closest approaches to the planet. These emissions are interpreted to arise from short-lived electrostatic discharges in the vicinity of Saturn. We have made a statistical study of their characteristics from the Voyager 1 and 2 high-band data of the PRA experiment (1.2 MHz to 40.2 MHz). In this paper, we compare the results obtained for the two encounters and describe in detail the appearance, intensity, and spectrum of the Saturn electrostatic discharges (SED). We show that the SED spectrum is likely smooth in the frequency range 1–40 MHz and extends down to 20 KHz. We have determined the period of the SED occurrence, which seems to be slightly different for Voyager 1 and 2 encounters (10 hours 9 min for the Voyager 1 encounter and 10 hours 00 min for the Voyager 2 encounter). An attempt to interpret the statistical results is presented.