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Titel |
The impact of gravity waves rising from convection in the lower atmosphere on the generation and nonlinear evolution of equatorial bubble |
VerfasserIn |
E. Alam Kherani, M. A. Abdu, E. R. Paula, D. C. Fritts, J. H. A. Sobral, F. C. Meneses |
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 ; 27, no. 4 ; Nr. 27, no. 4 (2009-04-07), S.1657-1668 |
Datensatznummer |
250016489
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Publikation (Nr.) |
copernicus.org/angeo-27-1657-2009.pdf |
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Zusammenfassung |
The nonlinear evolution of equatorial F-region plasma bubbles under varying ambient ionospheric conditions
and gravity wave seeding perturbations in the bottomside F-layer is studied. To do so, the gravity
wave propagation from the convective source region in the lower atmosphere to the thermosphere
is simulated using a model of gravity wave propagation in a compressible atmosphere. The
wind perturbation associated with this gravity wave is taken as a seeding perturbation in the
bottomside F-region to excite collisional-interchange instability. A
nonlinear model of collisional-interchange instability (CII) is implemented to study the influences
of gravity wave seeding on plasma bubble formation and development. Based on observations during the
SpreadFEx campaign, two events
are selected for detailed studies. Results of these simulations suggest that gravity waves can
play a key role in plasma bubble seeding, but that they are also neither necessary nor certain to
do so. Large gravity wave perturbations can result in deep plasma bubbles when ionospheric
conditions are not conducive by themselves; conversely weaker gravity wave perturbations can
trigger significant bubble events when ionospheric conditions are more favorable. But weak gravity
wave perturbations in less favorable environments cannot, by themselves, lead to strong plasma
bubble responses. |
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