submitted to Conference Proceeding book: 1 September 2000

Charging Processes for Dust Particles in Saturn's Magnetosphere

A. L. Graps and E. Gr\"un 

Max-Planck-Institut f\"ur Kernphysik, 
Saupfercheckweg 1, 
69117 Heidelberg, Germany


ABSTRACT

We investigated the electrostatic charging behavior of
submillimeter-sized dust particles located in Saturn's magnetosphere.
The charging effects we considered included electron/ion capture from
the magnetospheric plasma, electron/ion capture from the solar-wind
plasma, the photoelectric effect from solar radiation, and secondary
electron emission from energetic electrons. In our results we show
charging times and equilibrium potentials for particles located in
different regions of Saturn's magnetosphere. We find that charging in
Saturn's magnetosphere is not particularly sensitive to the dust
particle's material properties.  The equipotential ranges from $\sim$-2~V at
3.5~R$_S$, decreasing to $\sim$-5~V at 6~R$_S$, and then increasing to
$\sim$-1.5~V at 10~R$_S$. The charging time for one micron-sized
particles is a few minutes, and for 0.01 micron-sized particles the
charging time is 6 hours (or more). The latter is a significant
fraction of Saturn's rotation period.