|
|
 |
|
|
Ann. Geophys., 23, 419-431, 2005
www.ann-geophys.net/23/419/2005/
© European Geosciences Union 2005
An extended TRANSCAR model including ionospheric convection: simulation of EISCAT observations using inputs from AMIE
P.-L. Blelly1,*, C. Lathuillère2, B. Emery3, J. Lilensten2, J. Fontanari1, and D. Alcaydé1
1Centre d’Etude Spatiale des Rayonnements, Toulouse, France
2Laboratoire de Planétologie de Grenoble, Grenoble, France
3High Altitude Observatory, Boulder (Co), USA
*Present address: Laboratoire de Physique et de Chimie de l’Environnement, Orleans, France
Abstract. The TRANSCAR ionospheric model was extended to account for the convection of the magnetic field
lines in the auroral and polar ionosphere. A mixed Eulerian-Lagrangian 13-moment approach was
used to describe the dynamics of an ionospheric plasma tube. In the present study, one focuses
on large scale transports in the polar ionosphere. The model was used to simulate a 35-h
period of EISCAT-UHF observations on 16-17 February 1993. The first day was magnetically quiet,
and characterized by elevated electron concentrations: the diurnal F2 layer reached as much
as 1012m-3, which is unusual for a winter and moderate solar activity (F10.7=130)
period. An intense geomagnetic event occurred on the second day, seen in the data as a strong
intensification of the ionosphere convection velocities in the early afternoon (with the
northward electric field reaching 150mVm-1) and corresponding frictional heating of the
ions up to 2500K. The simulation used time-dependent AMIE outputs to infer flux-tube transports
in the polar region, and to provide magnetospheric particle and energy inputs to the ionosphere.
The overall very good agreement, obtained between the model and the observations, demonstrates
the high ability of the extended TRANSCAR model for quantitative modelling of the high-latitude
ionosphere; however, some differences are found which are attributed to the precipitation of
electrons with very low energy. All these results are finally discussed in the frame of
modelling the auroral ionosphere with space weather applications in mind.
Full Article in PDF (2930 KB) |
|
|
