  The observed disparity between the radial dependence of the ion and electron
densities measured by the Cassini plasma and radio science instruments are used
to show that the region between the outer edge of Saturn's main rings and its
tenuous G-ring is permeated with small charged grains (nanograins). These
grains emanate from the edge of the A-ring and from the tenuous F-ring and
G-ring. This is a region of Saturn's magnetosphere that is relatively
unexplored, but will be a focus of Cassini's F-ring orbits prior to the end of
mission in September 2017. Confirmation of the grain densities predicted here
will enhance our ability to describe the formation and destruction of material
in this important region of Saturn's magnetosphere.
