31st Annual Meeting of the DPS, October 1999
Session 73. Outer Planet Physics I
Contributed Oral Parallel Session, Friday, October 15, 1999, 2:00-3:20pm, Sala Kursaal

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[73.08] Model of an Electrodynamic Deceleration Event in Jupiter's Polar Thermosphere

N. Achilleos, S. Miller (University College London), M. Dougherty (Imperial College), T. Stallard (University College London)

We present a simulation using the JIM (Jovian Ionospheric Model) in which the electrodynamic interaction between the planet's magnetosphere and ionosphere is represented as a time-dependent potential drop across the model auroral oval. We find that for realistically high (\geq 100 kV) trans-auroral potentials, the flow of neutral thermospheric gas is strongly coupled to the motion of ions at the auroral ionization peak (at pressure ~ 0.1 \mubar).

The neutral winds re-adjust rapdily to time-dependent changes in the potential and thus in the ionospheric current system. Our simulations indicate that this re-adjustment can be on timescales of the order of hours. Our results also show that significant variations in magnetospheric plasma flow, perhaps due to mass-loading events, are capable of producing observable changes in velocities in the Jovian ionosphere.

The author(s) of this abstract have provided an email address for comments about the abstract: na@mortimer.phys.ucl.ac.uk

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