Ultra-relativistic electrons in Jupiter's radiation belts.

Ground-based observations have shown that Jupiter is a two-component source of microwave radio emission: thermal atmospheric emission and synchrotron emission from energetic electrons spiralling in Jupiter's magnetic field. Later in situ measurements confirmed the existence of Jupiter's high-energy electron-radiation belts, with evidence for electrons at energies up to 20[?]MeV. Although most radiation belt models predict electrons at higher energies, adiabatic diffusion theory can account only for energies up to around 20[?]MeV.

Outburst of Jupiter's synchrotron radiation after the impact of comet Shoemaker-Levy 9.

Jupiter's nonthermal microwave emission, as measured by a global network of 11 radio telescopes, increased dramatically during the Shoemaker-Levy 9 impacts. The increase was wavelength-dependent, varying from approximately 10 percent at 70 to 90 centimeters to approximately 45 percent at 6 and 36 centimeters. The radio spectrum hardened (flattened toward shorter wavelengths) considerably during the week of impacts and continued to harden afterward.

Io-Related Radio Emission from Jupiter.

As evidenced by spectra of Jupiter's decametric radio emissions from 1960 through 1964, Jupiter's satellite Io acts to induce much of the emission and influences the spectral character of the emission. The emission pattern of Io-related emission is derived, and possible interaction mechanisms to explain the Io effect are discussed.

Faraday Rotation on Decametric Radio Emissions from Jupiter.

Some decametric radio emissions from Jupiter observed recently exhibit effects which are attributable to Faraday rotation within the earth's ionosphere. We present the evidence for the presence of Faraday rotation and discuss its origin. Identification of the magnetoionic mode in which the emission is generated at Jupiter appears possible, although near the limit of accuracy of our present observations.