Viscosity in Saturn's rings

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Abstract
We discuss the technique of estimating the viscosity in Saturn’s rings from the damping rate of waves observed to be propagating within the rings. Previously published attempts rely on spiral density waves as a diagnostic, and the wavetrains used in the analyses suffered significant complications that compromised the interpretations. We present a new method that considers the damping of spiral bending waves, a diagnostic which is largely free of,major complications. We deduce a kinematic viscosity of 260 (+150, -100) cm2/s for the middle of the A ring where bending waves have been excited by the 5:3 vertical resonance with Mimas. This value implies upper limits on the particle velocity dispersion and local ring thickness of 0.4 cm/s and 30 m, respectively.