ABSTRACT
Theoretical model is presented to study the Instabilities driven by field-aligned flows and formation of nonlinear electrostatic structures in Oxygen-Hydrogen (0-H) Plasma of upper ionosphere where ion temperature is closer to electron temperature. The flow of two ion species produces low frequency ion acoustic waves (lAWs) at different frequencies and wavelengths. It is shown that purely growing D’ Angelo instability becomes an oscillatory instability in the two ion plasma due to mode coupling. If the shear in the flow is in negative direction the dispersion relation of IAW is modified and parallel phase velocity of the wave shifts out of the region of heavy Landau damping. In the nonlinear regime, the modified ion acoustic wave (mlAW) produces KdVsolitons. This theoretical model is a general model for the two ion species plasma are here it is applied to the upper ionosphere. The results are in agreement with the observations of several satellites.
Keywords: lnstabilities; Nonlinear; Plasma; Mode coupling
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