A theory of Jovian shadow bursts

The shadow events in the dynamic spectra of Jovian decametric emission are explained as the result of interaction between electron bunches responsible for S and L emissions. The relevant dispersion relation is derived for the fast extraordinary mode in the cold magnetospheric plasma in the presence of S and L electron bunches. The growth rate of the synchrotron maser instability is studied in the presence and absence of S-electrons. It is shown that the synchrotron maser instability responsible for L-emission can be temporarily quenched by the invasion of S-electrons, thereby stopping the L-emission. The theory accounts for various observed features of the shadow events.