Dielectric Model for Electromagnetic Waves Generated in the E-Layer of the Earth's Ionosphere by Infrasound

摘要

A dielectric model for waves of the Earth's ionosphere is developed. In doing so, in comparison to the wellknown dielectric wave model by R.O. Dendy [1] for homogeneous systems, the stratification of the atmosphere is taken into account. Moreover, within the frame of many-fluid magnetohydrodynamics also the momentum transfer between the charged and neutral particles is considered. Acoustic-type waves causing the excitation of electromagnetic waves in the warm, weakly-collisional E-layer are introduced in the magnetohydrodynamic system by a fluctuating neutral-particle component. Models of the altitudinal scales of the plasma parameters and the electromagnetic wave field are derived. In case of the electric wave field, a method is given to calculate the altitudinal scale based on the Poisson equation for the electric field and the magnetohydrodynamic description of the particles. Further, an expression is derived to estimate the temperatur changes in the E-layer because of the propagation of acoustic-type wave modes and the generation of the electromagnetic waves. And last not least, a formula is derived to determine the dispersion and polarisation of the excited electromagnetic waves, which is necessary to find quantitative results for the turbulent heating of the ionospheric E-layer. The electromagnetic waves which may be obtained in the E-layer by the newly developed dielectric model are, amongst others, Alfvén and magnetoacoustic modes, but also waves of the Farley-Buneman type.