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Jovian S‐bursts are intense impulsive decameter radio spikes drifting in frequency in tens of milliseconds over several hundreds of kHz up to a few MHz. Their generation scenario has been much debated for 30 years. The automated analysis of an extensive set of digital radio observations at very high temporal and spectral resolutions is presented here. It strongly suggests that S‐bursts are the cyclotron‐maser emission of electron populations with ∼5 keV energy, accelerated near Io and then in quasi‐adiabatic motion along magnetic field lines connecting the Io torus to Jupiter's auroral regions. This scenario is consistent with Voyager observations of Alfvèn waves near Io's wake and with recent infrared observations of the Io flux tube footprint. The total energy, velocity and pitch angle of the radiating electrons, and the extent of the bursts radiosources are deduced from the radio measurements, which appear as a promising remote sensing tool for the Jovian magnetosphere, and possibly that of other “radio” planets.

A new two-channel digital receiver that can be used for observing both stationary and sporadic radio sources in the decameter wave band is presented. Current implementation of the device operating at the sampling frequency of 66 MHz is described in detail, including the regimes of waveform capture, spectrogram analysis, and coherence analysis (cross covariance between the two inputs). Various issues pertaining to observational methods in the decameter waveband affected significantly by man-made interferences have been taken into account in the receiver design, as well as in the architecture of the interactive software that controls the receiver parameters in real time. Two examples of using the receiver with the UTR-2 array (Ukraine) are reported: S-bursts from Jupiter and low-frequency wide-band single pulses from the pulsar PSR0809+74

Abstract. At least six intense nonthermal planetary radio emissions are known in our solar system: the auroral radio emissions from the Earth, Jupiter, Saturn, Uranus and Neptune, and the radio bursts from the Io-Jupiter flux tube. The former are thought to be driven by the solar wind flow pressure or energy flux on the magnetospheric cross-section, while the latter is a consequence of the Io-Jupiter electrodynamic interaction. Although in the solar wind, the flow ram pressure largely dominates the magnetic one, we suggest that the incident magnetic energy flux is the driving factor for all these six radio emissions, and that it can be estimated in the same way in all cases. Consequences for the possible radio emission from extrasolar planets are examined. "Hot Jupiters", if they are magnetized, might possess a radio emission several orders of magnitude stronger than the Jovian one, detectable with large ground-based low-frequency arrays. On another hand, "giant" analogous to the Io-Jupiter interaction in the form of a pair star/hot-Jupiter are unlikely to produce intense radio emissions, unless the star is very strongly magnetized.

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