Radio detection, especially at high time-frequency (t-f) resolutions, is a powerful means of remotely studying electron acceleration processes, provided that the radio generation process is well identified and understood. Low radio frequencies (typically ≤100-200 MHz) are likely to be a preferred spectral domain to detect exoplanetary magnetospheres and star-planet interactions. Detection of radio bursts is also a means to overcome the hindering presence of interference and of ionospheric propagation effects at these low frequencies. In planetary solar system magnetospheres, the occurrence of radio bursts drifting in the t-f plane is common. The best documented case concerns the Jovian “S-bursts” induced by the Io-Jupiter interaction, the generation of which has been modelled, from the acceleration of electrons by Alfvén waves (themselves amplified by the ionospheric Alfvén resonator to the growth rate of radio emissions). We have developed a detection method of drifting radio bursts in massive high t-f resolution data, and have applied it to Jupiter observations with the Nancay Decameter Array. Beyond the expected many Io-Jupiter S-bursts, we present the first detection of decameter S-bursts related to the Ganymede-Jupiter interaction and to the main Jovian aurora. This reveals the ubiquitous character of Alfvénic electron acceleration and of the Alfvén resonator in Jupiter's high-latitude regions. We estimate the Alfvén wave periods and the energy of accelerated electrons. Two populations are found to co-exist, with different energies (a few keV and a few hundred eV). The technique developed for achieving these detections may become important for characterizing inaccessible astrophysical sources such as exoplanets.