HR: 1340h
AN: SM33A-1254    [Abstracts]
TI: Spatially and Chemically Segregated Energization of Jupiter's Magnetosphere
AU: * Saur, J
EM: joachim.saur@jhuapl.edu
AF: JHU/APL, 11100 Johns Hopkins Rd, Laurel, MD 20723 United States
AU: Pouquet, A
EM: pouquet@ucar.edu
AF: NCAR, P.O. Box 3000, Boulder, 80307 United States
AU: Matthaeus, W H
EM: yswhm@bartol.udel.edu
AF: Bartol Research Institute, 217 Sharp Lab, Newark, 19716 United States
AB: The small-scale magnetic field fluctuations in Jupiter's middle magnetosphere undergo a turbulent cascade which transports the energy in the fluctuations to smaller length scales. This kind of turbulence is in essence a bath of weakly, but non-linearly interacting Alfven waves. The turbulent cascade is non-dissipative, but when the length scales of the fluctuations approach kinetic length scales their energy is converted into particle acceleration and heating. Key kinetic length scales for Alfvenic turbulence are the electron inertial length scale and the ion-acoustic gyroradius. We show in our presentation that the electron inertial length scale is the crucial dissipation length scale inside of 27 RJ (Jovian Radii) while the ion-acoustic gyroradius dominates outside of 27 RJ. The electron inertial length scale maximizes at the high latitudes, while the ion-acoustic gyroradius maximizes in the equatorial current sheet for the heaviest ions. This ordering implies that the Jovian magnetosphere is energized inside of 27 RJ predominantly at high latitudes where the lightest ions (i.e., protons) prevail. Outside of ~27 RJ, the heavier magnetospheric ions (i.e., sulfur) are energized in the equatorial current sheet. Observational support for this segregated energization picture comes from recent observations of energetic particles ($>$50 keV; Mauk et al. [2004]) which show that protons dominate the total energy flux inside of about 25 RJ and sulfur ions dominate the energy flux outside of ~25 RJ.
DE: 5737 Magnetospheres (2756)
DE: 6220 Jupiter
DE: 2736 Magnetosphere/ionosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting