DPS Pasadena Meeting 2000, 23-27 October 2000
Session 49. Rings Posters
Displayed, 1:00pm, Monday - 1:00pm, Friday, Highlighted Tuesday and Thursday, 3:30-6:30pm, C101-C105, C211

## [49.10] Fingerprints'' of the size-distribution in planetary rings

F. Spahn (Univ. Potsdam), M. Sremcevic (Univ. Belgrade)

We extend the Markov-model of gravitational scattering by moonlets in planetary rings to viscous diffusion. The latter process counteracts the generation of structures due to the larger ring-boulder. As a result two types of steady state patterns evolve: \, i) a propeller'' shaped structure for moonlets D < 1km in size \, ii) a circumferential gap (+ringlet) for larger moonlets. \, The radial and the azimuthal extent scale with the Diameter D of the moonlet [radial: \propto D (for D < 3 km in diameter) or \propto D2 (for D> 3 km); azimuthal: \propto D^3/\nu, \, with \nu - kinematic viscosity]. In this way the size distribution and also the viscous properties of the ring matter could be probed by the high resolution images of the Cassini spacecraft in the near future.