Numerical moddeling of the ionospferic plasma by means of the stochastic approach

Physical processes in the ionosphere are still a topical subject of research. Of particular interest is the process of ionospheric modification by the action of a powerful wave. Strong interaction of a powerful heating wave with the ionospheric plasma in the F-layer usually leads to parametric instability, which occurs at the Langmuir resonance point near the reflection point of the pump wave. Parametric instability of the plasma leads to effective excitation of electron and ion plasma waves and the formation of a region of Langmuir turbulence. Nonlinear processes of Langmuir turbulence lead to the formation of cavitons (long-lived caverns of plasma density) disturbances in the distribution of the average plasma concentration.

In this report, a stochastic approach is constructed that takes into account the diffusion mechanisms of electron motion and Landau damping effects. A modification of the stochastic approach is given that takes into account collisions of electrons with neutral particles. In this paper, it is proposed to apply an approach based on Kramers' theory of overcoming the potential barrier. It is shown that this approach is in good agreement with the existing estimates obtained within the framework of Sagdeev's quasilinear model. Arguments are given in favor of the adequacy of this approach.