Long-term behavior of Jovian bKOM and nKOM radio emissions observed during the Ulysses-Jupiter encounter

Abstract

We present observational evidence that the long-term behavior of Jovian bKOM and nKOM radio emissions observed during the Ulysses-Jupiter encounter was controlled by the sector structure of the solar wind. Specifically, we found brightenings in the Jovian bKOM emission, followed by a sudden cessation of the bKOM emission and an onset of an nKOM “event” that lasted for some 120 hours. This sequence of events was observed to recur every ∼12 or 25 days from October, 1991 to mid-January, 1992 when Ulysses was inbound toward Jupiter and at Jovian latitudes <2.3°. These observations indicate that the solar wind structures, which influence the dynamics of Jupiter's magnetosphere, in turn control the radio emissions generated inside the magnetosphere.