Terrestrial Propagation of Long Electromagnetic Waves


Book Description

Terrestrial Propagation of Long Electromagnetic Waves deals with the propagation of long electromagnetic waves confined principally to the shell between the earth and the ionosphere, known as the terrestrial waveguide. The discussion is limited to steady-state solutions in a waveguide that is uniform in the direction of propagation. Wave propagation is characterized almost exclusively by mode theory. The mathematics are developed only for sources at the ground surface or within the waveguide, including artificial sources as well as lightning discharges. This volume is comprised of nine chapters and begins with an introduction to the fundamental concepts of wave propagation in a planar and curved isotropic waveguide. A number of examples are presented to illustrate the effects of an anisotropic ionosphere. The basic equations are summarized and plane-wave reflection from a dielectric interface is considered, along with the superposition of two obliquely incident plane waves. The properties of waveguide boundaries are implicitly represented by Fresnel reflection coefficients. Subsequent chapters focus on boundaries of the terrestrial guide; lightning discharges as a natural source of extremely-low-frequency and very-low-frequency radiation; and the mode theory for waves in an isotropic spherical shell. This book will be a useful resource for students and practitioners of physics.




Propagation of Radio Waves at Frequencies below 300 Kc/s


Book Description

Propagation of Radio Waves at Frequencies Below 300 KC/S covers the proceedings of the Seventh Meeting at the AGARD Ionospheric Research Committee, held in Munich, Germany on September 17-21, 1962. This book is organized into eight parts encompassing 32 chapters. The first parts deal with research studies concerning the electron density distribution and some properties of the lower ionosphere, as well as the effect of D-layer irregularities on radio wave propagation. The next parts explore the low frequency propagation in the lower ionosphere, the measurement of oblique incidence, and the statistical frequency spectrum of radio noise below 300 kc/s. The remaining chapters discuss the diurnal changes, the statistical prediction, the mode theory, and the propagation of very and extremely low frequency radio waves in the ionosphere. These chapters also examine the Earth resonance. This book will prove useful to astronomers, astrophysicists, and space scientists.













Ionospheric Radio


Book Description

This introductory text replaces two earlier publications (Davies 1965, 1969). Among the topics: characteristics of waves and plasma, the solar-terrestrial system, the Appleton formula, radio soundings of the ionosphere, morphology of the ionosphere, oblique propagation, importance of amplitude and phase, earth-space propagation. Annotation copyrighted by Book News, Inc., Portland, OR




ELF and VLF Electromagnetic Field Effects


Book Description

Recent emphasis upon the importance of the physical environment has made science and the public even more cog nizant of the many components of the biosphere. While much attention has been given to ionizing electromagnetic stimuli which causes blatant and unalterable changes in biological systems, relatively little research has been concerned with those electromagnetic signals whose frequencies overlap with time-varying processes in living organisms. Extremely low frequency (ELF) electromagnetic fields can occur as waves between about I Hz to 100 Hz or as short pulses within this range of very low frequency (VLF) and higher frequency sources. The natural occurrence of ELF signals is associated with weather changes, solar disturbances and geophysical ionospheric perturbations. Man-made sources have also been reported. Certain physical properties of ELF signals make them excellent candidates for biologically important stimuli. Unlike many other weather components, ELF signals have the capacity to penetrate structures which house living organ isms. ELF wave configurations allow long distance propaga tional capacities without appreciable attenuation of inten sity, thus making them antecedent stimuli to approaching weather changes. Most importantly, ELF signals exhibit the frequencies and wave forms of bio-electrical events that occur within the brain and body. Thus resonance inter actions between animal and nature become attractive possi bilities.




ELF-VLF Radio Wave Propagation


Book Description

This volume is based on lectures and discussions presented at a NATO Advanced Study Institute on ELF and VLF Radio Wave Propagation, which was held in Norway April 1974. The study of propagation of electromagnetic waves with frequen cies below 100 kHz has long traditions in ionospheric physics. To-day, this frequency range is still of great importance, both to the physicist, who uses the waves as diagnostic tools to study the earth's environment and to the engineer who exploits the characteris tics of these waves to improve communications, navigation and timing systems. In recent years the active interest in the field has led to very rapid progress in the development of propagation theory as well as in the application of this theory to the solution of practical problems. The intention of the Organizing Committee for this Conference was to bring together theoreticians and experi mentalists working on the various aspects of wave propagation, in order to stimulate a fruitful discussion and exchange of ideas.