HR: 1330h
AN: SM22B-0242    [PDF]
TI: The Local Time Variation of the Structure of Jupiter's Magnetosphere: Inferences for Plasma Loss
AU: * Kivelson, M G
EM: mkivelson@igpp.ucla.edu
AF: UCLA/IGPP, 6843 Slichter Hall, 405 Hilgard Ave., Los Angeles, CA 90095-1567 United States
AU: Southwood, D J
EM: david.southwood@esa.int
AF: ESA Headquarters, 8-10 rue Mario-Nikis, F-75738, Paris, Cedex 15 France
AB: Exploiting the capability given by the magnetometer data set from the entire Galileo mission as well as previous data from spacecraft flybys, we survey the local time structure of Jupiter's magnetosphere. We pay particular attention to the current sheet and regions beyond. The sheet is thinnest in the morning hours; it can thicken by more than a factor of 10 during the rotation to dusk. At the same time, the distinctive outer magnetospheric region typically present beyond the edge of the sheet in the morning side and often pervaded by field nulls is also less clear by late afternoon. The magnetodisk appears to remain thick in the pre-midnight hours and to thin increasingly as it rotates past midnight towards the dawn flank. Using the appearance of brief bursts of northward field in the sheet as a proxy for the occurrence of reconnection, we note that such signatures appear more often and closer to Jupiter the closer one moves across the nightside towards dawn. As contrasted with Earth's magnetotail in which dynamic reconnection is followed by a significant change of field configuration, Jupiter's magnetotail field remains highly distended following the bursts of activity and gives little evidence for sustained reconnection anywhere inside the region surveyed by Galileo. We conclude that the data best fit with a pattern of plasma and flux circulation in the magnetosphere wherein a large fraction of the magnetodisk plasma is lost in each planetary rotation and where morning-afternoon asymmetries as well as day-night asymmetries in dynamics are fundamental.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2756 Planetary magnetospheres (5443, 5737, 6030)
DE: 5719 Interactions with particles and fields
DE: 5737 Magnetospheres (2756)
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting