S-BURSTS OF JOVIAN DECAMETRIC RADIO EMISSION STORMS UNDER THE INFLUENCE OF LOW AND HIGH FREQUENCY MHD DISTURBANCES IN STREAMER-LIKE SOURCES

There are analyzed a model for the DAM-bursts radiation by maser-cyclotron generation mechanism in the streamer-like sources that have been activated on ionization processes and MHD waves of high and low frequencies in Jupiter magnetosphere. It was accounted that the ion-atom collision processes in the magnetosphere of low-ionized plasma change the velocities and decay times of MHD waves at ultralow frequencies, because of the high and low frequency MHD disturbances have different properties and do different functions in Jupiter magnetosphere. Thus, it is shown that the typical periodicities of high frequency (HF) in S-burst-storm pattern, of about 0.5 kHz and higher 1 Hz, may be associated with HF Alfven waves, which activate the processes of DAM burst radiations. On the other hand, the typical low-frequency (LF) periodicities of S-storm radiation, of about 5 and 20 min time-scales, may be associated with LF Alfven waves, which activate the processes of plasma ionization and its stratification into streamers. There was studied the propagation process of HF and LF MHD waves in Jupiter magnetosphere, when plasma flux is streaming inside the Io-Jupiter tube. Then, the process of maser generation of DAM bursts in presence of HF MHD-waves is investigated. We show that HF-Alfven waves perturb the electron plasma density and its velocity distribution, which give us the conditions to emit the DAM radiation effectively. Finally, we discussed the particular properties of HF Alfven and MS wave modes in the plasma streamers, and how they form the DAM bursts, and next one, it was shown how to fit the observational data to the plasma processes that may be to work in this source model.