HR: 17:25h
AN: SM12C-06 INVITED     [PDF]
TI: Auroral Emissions of Jupiter and the Galilean Satellites
AU: * Gladstone, R
EM: rgladstone@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166 United States
AU: Bhardwaj, A
EM: bhardwaj_spl@yahoo.com
AF: Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum, 695022 India
AU: Retherford, K
EM: kretherford@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166 United States
AB: The different types of Jupiter's aurora are most naturally separated by magnetic latitude. At the highest latitudes (near the magnetic poles) the auroral emissions are connected with the outer magnetosphere and are patchy and highly variable, e.g., FUV flares with minute time scales and pulsating x-ray hot spots (coincident with quasi-periodic radio bursts and IR hydrocarbon auroras). The main auroral oval is formed by the breakdown of magnetospheric plasma co-rotation at L=20-30. This breakdown leads to a current system connecting the equatorial magnetosphere with the polar ionosphere. A paucity of charge carriers near Jupiter is thought to lead to field-aligned potential drops in the upward current (from the ionosphere toward the magnetosphere). The resulting electric fields accelerate electrons into the upper atmosphere where they impact H$_2$, leading to the emissions of the main oval. It is possible that the variable emissions at higher latitudes are due to a more intermittent return current. At lower latitudes there are faint diffuse auroras and also the flux tube footprint auroras of the Galilean satellites (no footprint has been seen yet for Callisto, but it would be very close to the main oval and hard to detect). Attached to the Io flux tube footprint is a tail of emission that extends downstream (relative to the direction of magnetospheric plasma flow past Io) for many tens of degrees. At the other end of the flux tubes, auroral emissions (as opposed to airglow emissions) have been observed at Io, Europa, and Ganymede. The study of these flux tubes, and their interactions with planet and satellite, would be an excellent goal for the JIMO mission.
DE: 0310 Airglow and aurora
DE: 2756 Planetary magnetospheres (5443, 5737, 6030)
DE: 6218 Jovian satellites
DE: 6220 Jupiter
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting