Characteristics of the Growth Increment of Drift-Dissipative Instability at the Fronts of Equatorial Plasma Bubbles

Abstract

Data from ground-based and satellite measurements, as well as the results of numerical modeling of the spatial structure of equatorial ionospheric bubbles, show that the longitude gradients of the logarithm of the electron concentration at the vertical boundaries of the bubbles can reach 10^–3 m^–1. At such electron concentration gradients, the development of drift-dissipative instability is possible. This can generate ionospheric plasma inhomogeneities with spatiotemporal scales characteristic of the equatorial F scatter. This article presents the results of calculations of the increment of the increase in gradient-drift instability on the side walls of ionospheric bubbles obtained on the basis of numerical modeling of the structure of equatorial plasma bubbles and the dispersion equation of drift-dissipative instability. The equatorial plasma bubbles were simulated on the basis of a two-dimensional numerical model of the Rayleigh-Taylor instability in the Earth’s equatorial ionosphere, which is suitable for modeling Rayleigh-Taylor and gradient type inhomogeneities that are strongly elongated along the magnetic field lines. The results of numerical experiments confirm that significant longitudinal plasma gradients at the fronts of the developed equatorial plasma bubble can generate drift-dissipative instability of the ionospheric plasma.