The Influence of Small Variations of Plasma Density on Conditions of Propagation of Electromagnetic Waves of the Whistle Range through the Morning Ionosphere

Abstract

The problem of the effect of plasma-density disturbances caused by infrasonic waves on the propagation and reflection of whistler electromagnetic waves incident on the morning ionosphere from above is considered. The influence of the parameters of an infrasonic wave on the coefficient of reflection of a whistler wave from the ionosphere from above in the general case of oblique propagation is studied. The strongest changes in the reflection coefficient of whistler waves are associated with concentration perturbations at heights of the order of 80–100 km, where the rate of decay of propagating electromagnetic radiation modes increases by more than an order of magnitude within a region that is quite local in height (less than 10–15 km). The features of the parametric effect of plasma density fluctuations in an infrasonic wave on the field of a whistler wave that reached the Earth’s surface are analyzed. At close values of the horizontal wavenumbers of the whistler and infrasonic waves, the field of the whistler wave near the Earth’s surface can increase by several times. The results obtained are important for understanding the relationship between magnetospheric wave processes of different nature. The study of the modulation of the coefficient of reflection of whistler waves from the ionosphere by infrasonic waves from above is relevant for explaining the operating modes of a plasma magnetospheric maser.