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All About Wave Equations
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
The most prominent instrument at HAARP is the Ionospheric Research Instrument (IRI), a high-power radio frequency transmitter facility operating in the High Frequency (HF) band. The IRI is used to temporarily excite a limited area of the ionosphere. Other instruments, such as a Very High Frequency (VHF) and an Ultra High Frequency (UHF) radar, a fluxgate magnetometer, a digisonde (an ionospheric sounding device), and an induction magnetometer, are used to study the physical processes that occur in the excited region.
Introduction
Published in Mike Tooley, David Wyatt, Aircraft Communications and Navigation Systems, 2017
Figure 1.12 shows the typical MUF for various angles of attack together with the corresponding working ranges. This diagram assumes a critical frequency of 5 MHz. This is the lowest frequency that would be returned from the ionosphere using a path of vertical incidence (see ionospheric sounding on page 8).
Wave field in a layer with a linear background profile and multiscale random irregularities
Published in Waves in Random and Complex Media, 2022
The improvement of environmental diagnostic tools depends on the development of a sounding signal model, which, in turn, is determined by the level of methods of describing wave propagation in an inhomogeneous medium. A peculiarity of irregularities of both ionospheric plasma and thermonuclear fusion plasma is their multiscale nature. At present, there is a set of methods that make it possible to describe the effect of a multiscale medium on the propagation of waves in a homogeneous (on average) or weakly inhomogeneous medium [1–3]. However, in the ionospheric sounding of the ionosphere and the sounding of thermonuclear plasma, it is necessary to take into account signal reflection in the presence of random irregularities.