HR: 1340h
AN: SM13B-0335    [Abstracts]
TI: Alfven Wave Travel Times in the Jovian Magnetosphere
AU: * Rachmeler, L A
EM: laurel.rachmeler@colorado.edu
AF: University of Colorado, University of Colorado, Boulder, Boulder, CO 80309
AU: Bagenal, F
EM: bagenal@colorado.edu
AF: University of Colorado, University of Colorado, Boulder, Boulder, CO 80309
AB: Measurements indicate that throughout most of the magnetosphere of Jupiter the plasma flow is dominated by rotation. This indicates that the magnetosphere is strongly coupled to the planet. Rotation confines the plasma towards the equator, the bulk motion is predominately rotational (albeit lagging behind rigid corotation) and Jupiter's atmosphere is the main source of energy. The low plasma density away from the equator limits the flow of currents that couple the equatorial plasma to the planet's polar regions. Furthermore, high densities and low magnetic fields in the plasma sheet result in low Alfven speeds and long travel times for Alfven waves between equator and the ionosphere. At larger distances from the planet, particularly on the dusk/night side, the time scale for Alfven waves to couple the plasma sheet to the jovian atmosphere becomes larger than the time scale for outward expansion. In this regime the plasma may be weakly coupled. We have developed an empirical model of the Alfven velocity in the magnetosphere of Jupiter and estimate the Alfven travel time between the equator and ionosphere as functions of local time and radial distance.
DE: 2730 Magnetosphere: inner
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2756 Planetary magnetospheres (5443, 5737, 6033)
DE: 2764 Plasma sheet
DE: 2768 Plasmasphere
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005