A generation model of small-scale geomagnetic field-aligned plasma inhomogeneities in the ionosphere

The dissipative instability of acoustic-gravity waves in the ionosphere is investigated. This instability results in formatting the horizontal periodi c structure of Conductivity disturbances which move with the velocities con siderably less than the sound velocity. In the presence of an external DC e lectric field the conductivity variations in the E-layer lead to an appeara nce of polarization electric fields propagating into the upper ionosphere a nd generating the plasma density variations at these altitudes. Estimates o f the space-time and amplitude characteristics of the excited ionospheric d isturbances and their comparison with the experimental data show that the d eveloped mechanism can be applied to generation model of the earthquake-rel ated small-scale plasma inhomogeneities:in the upper ionosphere. (C) 1998 E lsevier Science Ltd. All rights reserved.