Gradient-Drift Instability Research in the Region of Developed Equatorial Plasma Bubbles

The results of numerical experiments, which involve calculations of the spatial distribution of the electron concentration and electric potential field formed as a result of the gradient-drift instability in the domain of developed equatorial plasma bubbles, are presented. A characteristic feature of equatorial plasma bubbles is the presence of large ratios of the electron concentration outside the plasma bubbles compared to their values inside the plasma bubbles. This creates large concentration gradients and high cross-field drift velocities relative to the Earth’s magnetic field lines. These conditions lead to the occurrence of large positive values of the increment of the gradient-drift instability, resulting in the enhancement of small-scale inhomogeneities in the ionospheric plasma with spatial-temporal scales characteristic of equatorial F-scattering. The results are consistent with previous studies by the authors, aimed at investigating the peculiarities of the increment of the gradient-drift instability. Unlike the previous works of the authors, the research in this study is carried out on the basis of direct numerical modeling of the process of development of heterogeneity specified in the form of a spatially limited wave. The model describes the processes of development and intensification of initial heterogeneities with characteristic sizes of several tens of meters. Thus, gradient-drift instability may be the cause of the generation of small-scale structure at the fronts of plasma bubbles in the evening and at night. In the works of other authors, the study was carried out outside the region of ionospheric plasma bubbles.