Physics of instabilities in planetary rings and the prediction of new Uranian satellites

Correlation analysis is used to prove resonance interaction between Uranian rings and new satellites predicted earlier. Instability of circular rings relative to the disturbance with the azimuthal number m=1 is shown; it may be the cause of the ring's eccentricity. This justifies the authors' hypothesis that the formation of eccentric rings of the protodisk around Uranus is due to unknown Uranian satellites. The hypothesis is no longer required of the existence of ''shepherd''-satellites in Uranian rings which have not been discovered by Voyager-2. A new accretion instability of the protodisk is described which may have served as generator of the birth of the large-scale structure of Saturn's rings. The discovery of the instability makes it possible to understand the origin of the hierarchic structure of Saturn's rings, since the mechanisms of the formation of narrow ringlets were investigated earlier. (author). 2 figs., 1 tab., 38 refs