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| Titel |
Geomagnetic disturbances on ground associated with particle precipitation during SC |
| VerfasserIn |
V. Safargaleev, A. Kozlovsky, F. Honary, A. Voronin, T. Turunen |
| 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 ; 28, no. 1 ; Nr. 28, no. 1 (2010-01-22), S.247-265 |
| Datensatznummer |
250016759
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| Publikation (Nr.) |
 copernicus.org/angeo-28-247-2010.pdf |
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| Zusammenfassung |
| We have examined several cases of magnetosphere compression by solar wind
pressure pulses using a set of instruments located in the noon sector of
auroral zone. We have found that the increase in riometric absorption
(sudden commencement absorption, SCA) occurred simultaneously with the
beginning of negative or positive magnetic variations and broadband
enhancement of magnetic activity in the frequency range above 0.1 Hz. Since
magnetic variations were observed before the step-like increase of magnetic
field at equatorial station (main impulse, MI), the negative declinations
resembled the so-called preliminary impulse, PI. In this paper a mechanism
for the generation of PI is introduced whereby PI's generation is linked to
SCA – associated precipitation and the local enhancement of ionospheric
conductivity leading to the reconstruction of the ionospheric current system
prior to MI. Calculation showed that PI polarity depends on orientation of the
background electric field and location of the observation point relative to
ionospheric irregularity. For one case of direct measurements of electric
field in the place where the ionospheric irregularity was present, the sign
of calculated disturbance corresponded to the observed one. High-resolution
measurements on IRIS facility and meridional chain of the induction
magnetometers are utilized for the accurate timing of the impact of solar
wind irregularity on the magnetopause. |
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