Dust-Plasma Interactions in Planetary Rings

  1. J. H. Waite Jr.,
  2. J. L. Burch and
  3. R. L. Moore
  1. C. K. Goertz

Published Online: 18 MAR 2013

DOI: 10.1029/GM054p0427

Solar System Plasma Physics

Solar System Plasma Physics

How to Cite

Goertz, C. K. (1989) Dust-Plasma Interactions in Planetary Rings, in Solar System Plasma Physics (eds J. H. Waite, J. L. Burch and R. L. Moore), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM054p0427

Author Information

  1. Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875900742

Online ISBN: 9781118664315

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Keywords:

  • Space plasmas;
  • Sun;
  • Magnetosphere;
  • Astrophysics

Summary

We discuss the electrostatic levitation of charged dust particles above Saturn's rings due to the enhanced surface electric field which exists in regions of enhanced plasma density. These density enhancements may be due to meteor impacts on the rings. Because the elevated dust moves relative to the plasma cloud a charge separation electric field in the azimuthal direction exists in the plasma cloud. This field causes a radial plasma motion. As the plasma moves more dust is elevated and the cloud leaves behind a radial dust trail—the spokes. The dust particles will settle down onto the ring after about half a Kepler period at a different radial distance thus transporting angular momentum in the radial direction. In addition the charged dust particles change their angular momentum due to electromagnetic forces. The net angular momentum transport can lead to significant mass transport in the ring and accounts nicely for the optical depth minimum at synchronous orbit. Small-scale optical depth variations are unstable to rapid growth. This instability may be able to account for the remarkable ring structure seen by Voyager. Finally we briefly discuss collective dust-plasma effects which may be important in the tenuous planetary rings.