JOVIAN S-BURSTS - THE EVENT OF 4 JANUARY 1993

We report on the analysis of Jovian millisecond radio bursts (S-bursts ) observed at the radio station Graz-Lustbuhel on 4 January 1993 and s imultaneously recorded at two other stations Nancay in France and Khar ko in Ukraine. The three radiotelescopes are separated in longitude by approximately 15-degrees, but located at nearly the same northern lat itude (congruent-to 48-degrees). This network allows us to use differe nt receivers with complementary characteristics (multichannel, spectro -analyser, spectro-polarimeter). At the Lustbuhel Observatory we have recorded the Jovian S-bursts with high time resolution of 2 ms, suffic ient to see the individual S-bursts and to study their phenomenology. The high resolution spectra permitted us to analyse more than 900 S-bu rsts, in particular the drift-rate being determined at round -33 MHz s -1, on average. On the other hand, from the Nancay (France) data we di stinguished fifteen S-burst patterns during half an hour with mainly r ight-hand polarization, in the frequency range 15 MHz to 31 MHz. If we take into account the spectra of different S-bursts (Riihimaa 1991) w e find that the drift of the S-burst pattern is a function of the stru cture, like the type b and type f. We have concluded that the source e missions of an S-burst pattern with positive and negative drift seem t o be different. Concerning the existence of correlation between the S- and L- bursts a confirmation is shown with respect to previous works.