PROBLEMS OF GEOCOSMOS

Proceedings of the 7th International Conference "Problems of Geocosmos" (St. Petersburg, Russia, 26-30 May 2008)
Fig.3 δfoF2(t) variations at different ionospheric stations for the Indonesian earthquake on 1.03.1985
DISCUSSION
Situations are presented when apparent TIDs in F2 layer of the ionosphere are presumably linked with
developing earthquake. We have given examples when they arose in quiet conditions, in conditions of isolated
substorm on the backgrounds of quiet ionosphere and during ionosphere storm with positive initial phase.
Undoubtedly, the above given examples do not cover entire spectrum of ionosphere variations.
The changes of electron concentration of F2 layer from storm to storm are significant in the sense that two
storms never existed with the same behavior of ionosphere parameters. The basic approach to select macro-scale
irregularities consists of the use of differences in dynamics of ionosphere variations, characteristic for disturbed
heliogeophysical conditions and in dynamics of TIDs, inconvertible under the shape and velocity of a motion,
but with the casual moments of occurrence. Identifications of the dynamics of TIDs require processing data for
the territories of hundreds of thousand square kms.
Basic differences between TIDs and effects of magnetosphere perturbations in F2 layer are:
♦During an ionosphere substorm electron concentration is incremented as a result of activity of zonal and
meridian electric fields as well as under IGW in the day time after preliminary decrease (Brunelly and
Namgaladze, 1988). The trajectories of movement of TIDs coincide with the arcs of the major circle, whereas
the perturbations, which arise as a result of IGW generation during a substorm, are usually spread from high
latitudes to low in a meridian direction. IGW generation is delayed by 1 hr with respect to the AE-index;
♦Ionosphere storm represents a continuous process lasting from several hours to several days. Parameter
variations have global character. In the absence of AE outbursts, positive impulses recorded in δfoF2(t) on the
background of negative storm phase can be related to seismic TIDs. Positive perturbations of electron
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