HR: 1340h
AN: SM13B-0343    [Abstracts]
TI: Isolated Warm Flux Tubes in the Inner Magnetosphere: Agents for Magnetic Flux Transport
AU: * Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: University of California Los Angeles, Inst. of Geophysics and Planetary Physics, 405 Hilgard Ave., Los Angeles, CA 90095-1567 United States
AU: Leisner, J S
EM: jleisner@igpp.ucla.edu
AF: University of California Los Angeles, Inst. of Geophysics and Planetary Physics, 405 Hilgard Ave., Los Angeles, CA 90095-1567 United States
AU: Khurana, K K
EM: kkhurana@igpp.ucla.edu
AF: University of California Los Angeles, Inst. of Geophysics and Planetary Physics, 405 Hilgard Ave., Los Angeles, CA 90095-1567 United States
AU: Dougherty, M K
EM: m.dougherty@ic.ac.uk
AF: Imperial College, Blackett Lab., Dept. of Physics, Prince Consort Rd., London, UK SW7 2AZ United Kingdom
AU: Kurth, W S
EM: wsk@space.physics.uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, 210 Van Allen Bldg., Iowa City, IA 52242 United States
AB: A surprising observation during the initial Saturn Insertion Orbit was the discovery of magnetic flux tubes, apparently isolated from similar plasma conditions, with depressed magnitudes in an otherwise quiet region of the E-ring plasma torus. These were not reported on previous missions (the flybys of Pioneer 11 and Voyagers 1 and 2), apparently as subsequent Cassini observations show, because these flux tubes are rare. At this writing they have been detected on only three passes through the E-ring. The tubes sometimes appear to be twisted, as would be appropriate if they were isolated tubes moving relative to other magnetospheric flux tubes. Also the tubes are inclined to neighboring flux tubes when observed away from the equator. The sense of the inclination is such that these tubes are less stretched and more dipolar than their neighbors. This suggests that these tubes are more buoyant than surrounding flux tubes and indeed electron density measurements with the plasma wave subsystem are greatly reduced. Thus these tubes appear to be the counterpart to the jovian flux tubes seen in the Io torus called depleted flux tubes. However, in the jovian case the flux tubes have an increased rather than decreased field strength. At both planets we interpret these tubes as agents for the return of `emptied' magnetic flux tubes, from which the mass loaded on the tubes has been removed, presumably by reconnection in the more distant magnetotail. The scarcity of these tubes may be a function of the infrequency of reconnection events (substorms?) together with their rapid return to the inner magnetosphere once formed.
DE: 5737 Magnetospheres (2756)
DE: 6275 Saturn
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005