ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-27-1657-2009 The impact of gravity waves rising from convection in the lower atmosphere on the generation and nonlinear evolution of equatorial bubble Alam Kherani E. 1 Abdu M. A. 1 de Paula E. R. 1 Fritts D. C. 2 Sobral J. H. A. 1 de Meneses Jr. F. C. 1 Instituto Nacional de Pesquisais Espaciais, Sao Jose dos Campos, SP, Brasil NorthWest Research Associates, Colorado Research Associates Division, Boulder, USA 07 04 2009 27 4 1657 1668 Copyright: © 2009 E. Alam Kherani et al. 2009 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/27/1657/2009/angeo-27-1657-2009.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/27/1657/2009/angeo-27-1657-2009.pdf

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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