Narrow-band kilometric radio emission as observed by the Galileo plasma wave instrument

Jovian narrow-band kilometric (nKOM) radio emissions have been well-studied, and are believed to have source regions near the outer edge of the Io torus. Recent investigations have indicated that these emissions increase in intensity associated with magnetic storm-like behavior in the Jovian magnetosphere. The orbit of Galileo affords the opportunity to pass close to the suggested source region near each perijove. We have examined the plasma wave spectra of nKOM on all orbital passes, and we present three cases in some detail. The nKOM emission is seen to increase in intensity at the outer edge of the plasma torus near the edge of the magnetic equator/current sheet crossings. Near perijove, and also associated with magnetic equator crossings, intense bursty (probably electrostatic) and narrow-banded emissions similar to upper hybrid emission seen at Earth are observed. We postulate that these emissions are related to the source of the nKOM emission.