37th DPS Meeting, 4-9 September 2005
Session 60 Planetary Magnetospheres
Poster, Thursday, September 8, 2005, 6:00-7:15pm, Music Foyer

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[60.12] Saturn's Magnetospheric Engine: The Magnetic Flux Return Cycle

C. T. Russell, J. S. Leisner, K. K. Khurana (IGPP/UCLA), W. S. Kurth (Univ. of Iowa), C. S. Arridge, M. K. Dougherty (Imperial College, U.K.)

The ubiquitous ion cyclotron waves in the quiescent E-ring torus from about 4 to 6 Rs signals the strong mass loading of the plasma torus via the pickup of water-group ions. To achieve a steady state the ions must be transported to a region in which they can be removed from the system. Since Saturn is a rapidly rotating gas giant, with a sizeable magnetic moment, the centrifugal force of the added plasma can reach values sufficient to cause radial, outward transport of the mass-laden flux tubes. These tubes must eventually reach the tail and, through reconnection, dump their load of ions down the tail. While this process removes ions, it alone does not maintain steady state because magnetic flux has been removed from the inner magnetosphere. To return magnetic flux to the inner magnetosphere requires moving emptied flux tubes inward against the centrifugally driven outward flux. We have identified such empty flux tubes on several occasions. They are warmer than the surrounding plasma and more dipolar, consistent with their lower mass content. We believe these emptied flux tubes complete the magnetic flux return cycle, replacing the magnetic flux carried away by the mass-loaded flux tubes.

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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.