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Faraday rotation in the Jovian decametric radiation (DAM) is a well-known phenomenon when performing observations from ground-based telescopes which are sensitive to linear polarization. It is due to the different phase velocity of the ordinary and extra-ordinary wave modes that results in a rotation of the major axis of the elliptically polarized Jovian decametric emission when propagating through a magneto-active plasma. The amount of rotation is frequency dependent and therefore the Faraday rotation can be well recognized on the dynamic spectra by intensity minima (when the major axis of the polarization ellipse is perpendicular to the antenna elements) and maxima (when the major axis is parallel to the antenna elements) as a function of frequency. The study of Faraday rotation allows remote sensing of the terrestrial ionosphere and/or the source regions of the decametric emission in the Jovian magnetosphere. Investigating Jovian decametric observations containing Faraday rotation made at the Kharkov radio-telescope (Ukraine), it is found that the polarization angle at Jupiter (orientation of the major axis of the polarization ellipse at the radio source) cannot unam-biguously be determined with these data. Results on the polarization angle of Jovian DAM already given in the literature are still contradictory. Also it is not yet clear whether or not the total amount of Faraday rotation observed is due to the terrestrial ionosphere or if there is additionally a considerable contribution from the Jovian magnetosphere. Using modeled Faraday rotation patterns derived by electromagnetic ray-tracing through a realistic terrestrial ionospheric model enable most of the conflicting results to be explained in the literature by systematic errors due to over-simplification made in the respective assumptions. It is concluded that the amount of Faraday rotation observed in Jovian DAM spectra can be explained by the terrestrial ionosphere. At least in the case of low ionospheric plasma densities, the quadratic formula Ω = C 0 + C 1 f 2 + C 2 f 4 is sufficient to describe the number of Faraday fringes Ω as a function of frequency. Also, the polarization angle is confirmed to be parallel to B at the Jovian source position.

Taking advantage of the direction finding capabilities of the Ulysses unified radio and plasma wave (URAP) experiment we derive the source locations and emission characteristics of the Jovian hectometric (HOM) and broadband kilometric (bKOM) emissions. Unlike previous studies we additionally determine the systematic error of the source direction due to the uncertainty of the antenna/ receiver calibration parameters. To obtain maximum accuracy when doing direction finding, we use HOM and bKOM events observed close to the Ulysses encounter with Jupiter. It is found that both emissions have their sources at the auroral zones of Jupiter, at dipole L shells between 7 and 11 for HOM in the northern hemisphere, and between 9 and 15 for the bKOM radiation observed at high southern latitudes after the Ulysses Jupiter encounter. For the analyzed HOM events the source location is usually between 40° and 130° central meridian longitude (CML) and 2200 and 0600 local time (LT), but probably there exist emissions from other longitudes and local times too. In contrast, the bKOM is emitted from a wide range of longitudes and local times as well. There is some evidence that both the kilometric and hectometric emissions are composed of a dominant component in the fast extraordinary (R-X) mode and a weaker ordinary (L-O) mode component. Due to the uncertainty in source direction determination the emission's cone half-angle (i.e. half-angle of the cone in which the emission is beamed) cannot be accurately determined. It is some 30°–90° for the HOM and about 40°–80° for the bKOM. The source location of bKOM is likely to be associated with open magnetospheric field lines whereas the HOM is located at field lines that connect the HOM radio sources with the inner Jovian plasma sheet and/or outer plasma torus. There is some evidence that the bKOM radio emissions are correlated with ultraviolet auroral activity.

For the Uranus smooth low frequency emission (SLF) two different (and contradictory) source locations (one polar, one equatorial) have been reported in the literature. Visibility studies show that polar source locations within a limited magnetic longitude range can be singled out, whereas a polar source distributed along the whole range of magnetic longitudes is compatible with observations. In this study we have computed intensity contours for comparison with the observed emission. Profiles obtained by a geometrical beaming model favor the equatorial source location.

By using PRA (Planetary Radio Astronomy), PWS (Plasma Wave System) and MAG (Magnetometer) data from Voyagers 1 and 2, essential features of the nightside Jovian plasma sheet are derived, and the density gradient of the corotating plasma structure in the middle Jovian magnetosphere is estimated. The PRA experiment gives information about the plasma wave polarization. The emission was found to be left hand polarized when the spacecraft was in the northern magnetic tail lobe, and right hand in the southern lobe. The PWS experiment enables the determination of a density profile of the Jovian plasma sheet from the knowledge of the low frequency cutoffs of nonthermal continuum radiation observed at 3 frequencies (f=562 Hz, f=1.0 kHz, f=1.78 kHz). The results are discussed and compared with those obtained from other investigations.