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The neutral wind field effects on the development of the
equatorial plasma bubbles have been simulated by a two dimen-
sional time-dependent model similar to that developed by Zal-
esak and Ossakow. The results indicate that when there exists
no neutral wind, any perturbation in the bottom-side of the
ionosphere density profile will be amplified by Gravitational
Rayleigh-Taylor instability and an up-welling bubble will form
as expected. When a weak zonal neutral wind exists and as long
as the bubble co-moves with the uniform wind,the bubbles will
reserve its simple structure. As the neutral wind becomes str-
onger, secondary structures called plumes will grow out from
the side-walls of the primary bubble. If the neutral wind has
strong vertical shear, east-west symmetry of plasma bubbles are
strong- ly distorted. We notice that patches and multiple
plumes struct- ures have been observed in the mid- and low-
latitude ionosphere. So a two-dimensional linear theory of
generalized GRT instabili- ty is present to explain the
generation mechanism of the second- ary structures, and it is
found that the secondary perturbation is especially unstable at
the bubble''s leading edges, even when the bubble has already
penetrated into topside ionosphere where linear GRT instability
theory predicts stable.
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