Measurements of radio frequency signals from lightning in Jupiter's atmosphere

During the descent of the Galileo probe through Jupiter's atmosphere, the l ightning and radio emissions detector (LRD) instrument measured radio frequ ency signals presumably from electrical discharges in the planet's atmosphe re. The LRD was the only instrument that provided remote sensing, as well a s in situ, measurements of atmospheric characteristics. The LRD measurement s are presented here and some estimates are given on the energetics and fre quency of occurrence of lightning in Jovian clouds. Propagation calculation s of RF discharges in the Jovian atmosphere system and the statistics data obtained by the LRD, together with one very distinct lightning waveform, pe rmit a unified and consistent interpretation of the data. We conclude that, at the time of probe entry, Jovian discharges occur with a rate about one hundredth that. of the global yearly average on Earth (Earth value is about . 6 flashes km(-2) yr(-1)) within about 15,000 km radius of the probe and t hat the average radiated power is of the order of 5 x 10(11) W. The change in the electric dipole moment in Jovian lightning is about 10(7) coulomb m, roughly 100 times that of a typical terrestrial discharge.