Characteristics of the Earth-ionosphere Waveguide for VLF Radio Waves


Book Description

The principal results of this technical note are graphical presentations of the attenuation rates, phase velocities, and excitation factors for the dominant modes in the earth-ionosphere waveguide.The frequency range considered is 8 kc/s to 30 kc/s. *The model adopted for the ionosphere has an exponential variation for both the electron density and the collision frequency, and the effect of the earth's magnetic field is considered.Comparison with published experimental data confirms that the minimum attenuation of VLF radio waves in daytime is approximtely at 18 kc/s, while at night it is somewhat lower.The directional dependences of propagation predicted by the theory are also confirmed by experimental data.(Author).










Low Frequency Wave-reflection Properties of the Equatorial Ionosphere


Book Description

A joint United States - Brazil experiment was conducted near the geomagnetic equator to confirm the theoretically predicted strong dependence of the ionospheric reflection properties on the azimuthal direction of wave propagation. Skywave delays, reflection coefficients, and polarization ellipses were measured at different frequencies, ranges, and azimuths. The results were compared with full-wave computer calculations for several ionospheric models. A series of high resolution waveforms showing the sunrise transition from night- to daytime conditions is included.




Ionospheric Space Weather


Book Description

This book describes essential concepts of, and the status quo in, the field of ionospheric space weather. It explains why our society on planet Earth and moving outwards into space cannot work safely, function efficiently, or progress steadily without committed and comprehensive research initiatives addressing space weather. These initiatives must provide space environment specifications, warnings, and forecasts, all of which need to be timely, accurate and reliable. Cause and effect models of the Earth’s ionosphere are discussed in terms of the spatial and temporal dimensions of background variability, storms, gradients, irregularities, and waves in both current and long-term research activities. Starting from dynamic processes on the Sun, in the interplanetary medium, and in the Earth’s magnetosphere, ionosphere, and atmosphere, the text focuses on the dominant features of the plasma medium under normal and extreme conditions over the European zone during the last few Solar Cycles. One of the book’s most unique features is a series of fundamental examples that offer profound insights into ionospheric climate and weather. Various approaches for acquiring and disseminating the necessary data and forecasting analyses are discussed, and interesting analogies are observed between terrestrial and space weather – both of which could produce lasting social consequences, with not only academic but also concrete economic implications. The book’s primary goal is to foster the development of ionospheric space weather products and services that are capable of satisfying the ever-growing demand for space-based technology, and are ready for the society of the not-so-distant future.




The Earth's Ionosphere


Book Description

The Earth's Ionosphere: Plasma Physics and Electrodynamics emphasizes the study of plasma physics and electrodynamics of the ionosphere, including many aeronomical influences. The ionosphere is somewhat of a battleground between the earth's neutral atmosphere and the sun's fully ionized atmosphere, in which the earth is embedded. One of the challenges of ionosphere research is to know enough about these two vast fields of research to make sense out of ionospheric phenomena. This book provides insights into how these competing sources of mass, momentum, and energy compete for control of the ionosphere. Some of the topics discussed include the fundamentals of ionospheric plasma dynamics; equatorial plasma instabilities; high-latitude electrodynamics; and instabilities and structure in the high-latitude ionosphere. Throughout this text only the region above 90 km are discussed, ignoring the D region entirely. This publication is a good source of information for students and individuals conducting research on earth's ionosphere.




Resonances in the Earth-Ionosphere Cavity


Book Description

This book on electromagnetic resonance phenomena describes a general approach to physical problems, ways to solve them, and properties of the solutions obtained. Attention is given to the discussion and interpretation of formal and experimental data and their links to global atmospheric conditions such as the dynamics of global thunderstorm activity, variations of the effective height of the lower ionosphere, etc. Schumann resonance is related to worldwide thunderstorm activity, and simultaneously, to global properties of the lower ionosphere. Transverse resonance is predominantly a local phenomenon containing information on the local height and conductivity of the lower ionosphere and on nearby thunderstorm activity. Transient events in ELF-VLF radio propagation are also treated. These are natural pulsed radio signals and/or abrupt changes of manmade VLF radio signals. The transients associated with cloud-to-ionosphere discharges (red sprites, blue jets, trolls) are discussed, and clarification of the underlying physical ideas and their practical applications to pioneer results achieved in the field recently are emphasised.




The Earth's Ionosphere


Book Description

Although interesting in its own right, due to the ever-increasing use of satellites for communication and navigation, weather in the ionosphere is of great concern. Every such system uses trans-ionospheric propagation of radio waves, waves which must traverse the commonly turbulent ionosphere. Understanding this turbulence and predicting it are one of the major goals of the National Space Weather program. Acquiring such a prediction capability will rest on understanding the very topics of this book, the plasma physics and electrodynamics of the system. - Fully updated to reflect advances in the field in the 20 years since the first edition published - Explores the buffeting of the ionosphere from above by the sun and from below by the lower atmosphere - Unique text appropriate both as a reference and for coursework