HR: 1340h
AN: SM53A-1087    [Abstracts]
TI: Modelling of Io-Jupiter decameter arcs, emission beaming and energy source
AU: Zarka, P
EM: philippe.zarka@obspm.fr
AF: LESIA, Observatoire de Paris, CNRS, UPMC, Universite Paris Diderot, 5 Place Jules Janssen, Meudon, 92190, France
AU: * Hess, S
EM: sebastien.hess@obspm.fr
AF: LESIA, Observatoire de Paris, CNRS, UPMC, Universite Paris Diderot, 5 Place Jules Janssen, Meudon, 92190, France
AU: * Hess, S
EM: sebastien.hess@obspm.fr
AF: LUTH, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 Place Jules Janssen, Meudon, 92190, France
AU: Ray, L C
EM: lray@colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, UCB392, Boulder, CO 80309-0392, United States
AU: Cecconi, B
EM: baptiste.cecconi@obspm.fr
AF: LESIA, Observatoire de Paris, CNRS, UPMC, Universite Paris Diderot, 5 Place Jules Janssen, Meudon, 92190, France
AU: Mottez, F
EM: fabrice.mottez@obspm.fr
AF: LUTH, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 Place Jules Janssen, Meudon, 92190, France
AB: The electrodynamic interaction between Io and Jupiter is known to lead to accelerated electrons in/near the Io flux tube. These electrons produce intense radio emissions in the hecto-decameter range, with specific arc shapes in the time-frequency plane depending on the hemisphere of origin of the emission and on the Io-Jupiter- observer geometry. Assuming radio wave generation by the cyclotron-maser instability and a Jovian magnetic field model, we simulate tf arc shapes as a function of the radio emission beaming and of the lead angle between the radio emitting field line and the instantaneous Io field line. An excellent fit is obtained for loss-cone driven emission, obliquely beamed in a hollow cone at ~70 degrees from the source magnetic field within a ~1 degree thick beam. The radio beaming angle obtained from our simulations is found to be consistent with empirically fitted beaming angle function, assuming a supplementary refraction effect in the dense regions of the Io flux tube. The lead angle giving the best fit is ~30 degrees in both hemispheres, not fully consistent with the propagation of the perturbation generated by Io via Alfven waves. Simulation of future Juno radio observations are briefly discussed.
DE: 6219 Io
DE: 6939 Magnetospheric physics (2700)
DE: 7534 Radio emissions
DE: 7815 Electrostatic structures
DE: 7845 Particle acceleration
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting