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| Titel |
Numerical modelling of the thermospheric and ionospheric effects of magnetospheric processes in the cusp region |
| VerfasserIn |
A. A. Namgaladze, A. N. Namgaladze, M. A. Volkov |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 14, no. 12 ; Nr. 14, no. 12, S.1343-1355 |
| Datensatznummer |
250012500
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| Publikation (Nr.) |
 copernicus.org/angeo-14-1343-1996.pdf |
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| Zusammenfassung |
| The thermospheric and ionospheric effects of
the precipitating electron flux and field-aligned-current variations in the cusp
have been modelled by the use of a new version of the global numerical model of
the Earth's upper atmosphere developed for studies of polar phenomena. The
responses of the electron concentration, ion, electron and neutral temperature,
thermospheric wind velocity and electric-field potential to the variations of
the precipitating 0.23-keV electron flux intensity and field-aligned current
density in the cusp have been calculated by solving the corresponding
continuity, momentum and heat balance equations. Features of the atmospheric
gravity wave generation and propagation from the cusp region after the electron
precipitation and field-aligned current-density increases have been found for
the cases of the motionless and moving cusp region. The magnitudes of the
disturbances are noticeably larger in the case of the moving region of the
precipitation. The thermospheric disturbances are generated mainly by the
thermospheric heating due to the soft electron precipitation and propagate to
lower latitudes as large-scale atmospheric gravity waves with the mean
horizontal velocity of about 690 m s–1. They reveal appreciable
magnitudes at significant distances from the cusp region. The meridional-wind-velocity
disturbance at 65° geomagnetic latitude is of the same order (100 m
s–1) as the background wind due to the solar heating, but is
oppositely directed. The ionospheric disturbances have appreciable magnitudes at
the geomagnetic latitudes 70°–85°. The
electron-concentration and -temperature disturbances are caused mainly by the
ionization and heating processes due to the precipitation, whereas the
ion-temperature disturbances are influence strongly by Joule heating of the ion
gas due to the electric-field disturbances in the cusp. The latter strongly
influence the zonal- and meridional-wind disturbances as well via the effects of
ion drag in the cusp region. The results obtained are of interest because of the
location of the EISCAT Svalbard Radar in the cusp region and the associated
observations at lower latitudes that will be possible using the existing EISCAT
UHF and VHF radars. The paper makes predictions for both these regions, and
these predictions will be tested by joint observations by ESR, EISCAT UHF/VHF
and other ground-based ionosphere/thermosphere observations. |
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