Nanograin densities outside Saturn's A-ring

TL;DR

This study uses Cassini data to reveal that small charged nanograins permeate the region outside Saturn's A-ring, originating from ring edges, affecting plasma densities and enhancing understanding of magnetospheric material dynamics.

Contribution

It identifies and characterizes the presence of nanograins outside Saturn's A-ring, a region previously unexplored, based on plasma and radio science measurements.

Findings

Nanograins are present outside Saturn's A-ring.

Nanograins originate from ring edges such as the F-ring and G-ring.

This region's nanograin density influences magnetospheric processes.

Abstract

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.