HR: 1340h
AN: P43B-1292    [Abstracts]
TI: Spokes in Saturn's B Ring: Could Lightning be the Cause?
AU: * Horanyi, M
EM: horanyi@colorado.edu
AF: LASP and Department of Physics, University of Colorado, Boulder, CO 80309-0392, United States
AU: Morfill, G E
EM: gem@mpe.mpg.de
AF: Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching, 85748, Germany
AU: Cravens, T E
EM: cravens@ku.edu
AF: Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045, United States
AB: Spokes are narrow markings across Saturn's B ring, most likely caused by a cloud of micron sized particles intermittently lofted from the larger boulders comprising the ring. They were observed by the Voyagers, the Hubble Space Telescope, and more recently the Cassini spacecraft in orbit around Saturn since 2004. There are a number of suggestions to explain the triggering and subsequent evolution of spokes. In general, it is expected that spokes form due to sudden, short-lived changes in the plasma environment of the rings. Most recently, lightning in Saturn's atmosphere was suggested to trigger spokes, based on Cassini observations of field-aligned high-energy electron beams. In this talk we discuss the physic of the expected interactions of the rings with high energy electron beams, and show that, based on terrestrial examples, the expected amount of charge released in a lightning event could increase the surface charge density of the rings to sufficiently high values to trigger spokes.
DE: 5759 Rings and dust
DE: 6015 Dust
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting