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| Titel |
Observations of Pc5 micropulsation-related electric field oscillations in the equatorial ionosphere |
| VerfasserIn |
C. A. Reddy, Sudha Ravindran, K. S. Viswanathan, B. V. Krishna Murthy, D. R. K. Rao, T. Araki |
| 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 ; 12, no. 6 ; Nr. 12, no. 6, S.565-573 |
| Datensatznummer |
250010913
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| Publikation (Nr.) |
 copernicus.org/angeo-12-565-1994.pdf |
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| Zusammenfassung |
| A 54.95-MHz coherent backscatter radar, an
ionosonde and the magnetometer located at Trivandrum in India (8.5°N, 77°E,
0.5°N dip angle) recorded large-amplitude ionospheric fluctuations and magnetic
field fluctuations associated with a Pc5 micropulsation event, which occurred
during an intense magnetic storm on 24 March 1991 (Ap=161).
Simultaneous 100-nT-level fluctuations are also observed in the H-component at
Brorfelde, Denmark (55.6°N gm) and at Narsarsuaq, Greenland (70.6°N gm). Our
study of the above observations shows that the E-W electric field fluctuations
in the E- and F-regions and the magnetic field fluctuations at Thumba are
dominated by a near-sinusoidal oscillation of 10 min during 1730-1900 IST
(1200-1330 UT), the amplitude of the electric field oscillation in the
equatorial electrojet (EEJ) is 0.1-0.25 mV m-1 and it increases with
height, while it is about 1.0 mV m-1 in the F-region, the
ground-level H-component oscillation can be accounted for by the ionospheric
current oscillation generated by the observed electric field oscillation in the
EEJ and the H-component oscillations at Trivandrum and Brorfelde are in phase
with each other. The observations are interpreted in terms of a compressional
cavity mode resonance in the inner magnetosphere and the associated ionospheric
electric field penetrating from high latitudes to the magnetic equator. |
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