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Ann. Geophys., 16, 1200-1211, 1998
www.ann-geophys.net/16/1200/1998/
© European Geosciences Union 1998
Electric field effects on ionospheric and thermospheric parameters above the EISCAT station for summer conditions
V. V. Klimenko1, Yu. N. Korenkov1, and M. Förster2
1West Department of IZMIRAN, Kaliningrad Observatory, Academy of Sciences, Russia
2GeoForschungsZentrum, Projektbereich 2.3, Telegrafenberg D-14473 Potsdam, Germany Fax : + 49 331 288 1238; e-mail: mf@gfz- Potsdam.de
Abstract. Numerical calculations of the thermospheric
and ionospheric parameters above EISCAT are presented for quiet geomagnetic
conditions in summer. The Global Self-consistent Model of the Thermosphere,
Ionosphere and Protonosphere (GSM TIP) was used. The numerical results were
obtained both with a self-consistent calculation of the electric fields of
magnetospheric and dynamo-action origin and with the magnetospheric electric
fields only. It was found that the dynamo-electric field has some effect on the
ionospheric convection pattern during quiet geomagnetic conditions. It has a
marked effect mainly on the zonal neutral wind component above EISCAT (±20 m/s
at 140 km altitude). We have studied the effects of various field-aligned
current (FAC) distributions on thermosphere/ionosphere parameters and we show
that a qualitative agreement can be obtained with region-I and -II FAC zones at
75° and 65° geomagnetic latitude, respectively. The maximum FAC
intensities have been assumed at 03–21 MLT for both regions with peak values of
2.5×10–7 A m–2 (region I) and 1.25×10–7 A m–2
(region II). These results are in agreement with statistical potential
distribution and FAC models constructed by use of EISCAT data. The lack of
decreased electron density in the night-time sector as observed by the EISCAT
radar was found to be due to the spatial distribution of ionospheric convection
resulting from electric fields of magnetospheric origin.
Key words. Electric fields and currents · Ionosphere-
atmosphere interactions · Modelling and forecasting
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