Macrostructure and microphysics of Saturn's E-ring

Observed optical and infrared properties of Saturn's E-ring are explained in terms of Mie scattering by a narrow distribution of ice spheres with an effective diameter of 2 to 2.5 microns, and an effective variance of 0.1 to 0.15. The spherical shape of the ring particles and their narrow size distribution imply that they had a molten origin, followed by quick freezing. Continued replenishment of the E-ring by volcanic eruptions on Enceladus seems plausible. The vertical structure of the E-ring consists of many layers. The stratification of the particles may be due to electrostatic levitation, similar to that experienced by particles in the spokes.