Download or read book Physics of Natural and HF Induced Ionospheric Disturbances and Their Effects on Radio Communication written by Lee, Min-Chang and published by . This book was released on 1985 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a theoretical study of ionospheric disturbances caused by either natural or man-made processes. Thirteen papers published in either technical journals or conference proceedings are compiled in this report, These papers discuss (1) the identification of the sources of free energy, the optimum conditions for plasma instabilities as the courses of naturally occurring ionospheric irregularities, and (2) the nonlinear effects leading to the HF ionospheric disturbances such as lower hybrid waves, upper hybrid waves, ionospheric irregularities, and geomagnetic field fluctuations. Originator-supplied keywords: Ohmic dissipation of Pederson current, High-latitude F region ionospheric irregularities, Thermal instabilities, Polar cap, Lower hybrid waves, Field aligned plasma density striations, Whistlers, Magnetostatic fluctuations, Filamentation instability, Thermal source, Geomagnetic field fluctuations, Ionospheric heating, Langumiur waves, Saturation spectrum of parametric decay instability, Upper hybrid waves, O-mode and X-mode pump waves, Pondermotive force, Plasma line enhancement, Beating current, Non-oscillatory modes, Oscillatory two-stream instability, Nonlinear effects, Spread F echoes, Modulational instability.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1986 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hf Communication Effects Physics and Chemistry of the Ionosphere written by R. C Whitten (Jr) and published by . This book was released on 1965 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ionosphere from 50 to 700 km is discussed in an attempt to provide information of value and interest to radio communicators. Diurnal, seasonal, and solar cyclical variations of the ionosphere are considered as well as effects of diffusion, turbulence and winds, tidal and wave motions, chemical reactions, and magnetic disturbances. Ionization by extreme UV photons, solar X-rays, and Lyman-alpha and cosmic radiation are presented as functions of solar activity. The ionization and deionization processes (dissociation, recombination, charge transfer, and ion-atom interchange) that control ion and electron densities in the ionosphere are discussed. Detailed models of (1) the quiet ionosphere, (2) sudden ionic disturbances, (3) polar cap absorption events, and (4) ionospheric and geomagnetic storms are developed. Current theories of ionospheric processes and phenomena are evaluated and remaining problems of interpretation pointed out. (Author).
Download or read book Effects of Ionospheric Scattering on Very Long Distance Radio Communication written by H.A. Whale and published by Springer. This book was released on 2013-12-01 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book HF VHF Radiowave Techniques for Investigating High Latitude Ionospheric Disturbances written by and published by . This book was released on 1991 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: The object of this contract was to develop a unified model for radio wave propagation in the 2-147 MHz band at high latitudes, especially during disturbances. This particularly included the analysis and measurement of the frequency dependence during polar cap absorption events and assessment of the effects of artificially induced perturbations on radio waves within this band. This project concentrated on single hop HF ionospheric propagation in the 2-30 MHz band and VHF meteor scatter in the 45-147 MHz band.
Download or read book Long Distance Propagation of HF Radio Waves written by Alexander V. Gurevich and published by Springer. This book was released on 1985-08 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of very long-distance and around-the-world propagation of HF radio waves becomes more urgent in connection with the problems of long distance ground-based radio communications, communications with space crafts and satellites, satellite-to-satellite communications, around-the-world radar scanning, around-the-world sounding of the ionosphere, etc. At pre sent, these investigations have acquired particular interest because transmit ters which make it possible to intentionally modify the ionospheric properties by powerful radio waves have become available. In the case of radio wave propagation over comparatively small distances (about 3000 - 5000 km, one - two hops), in a first approximation, the iono sphere can be considered homogeneous in the horizontal direction. The radio wave propagation theory in a horizontally-homogeneous, i. e. , spherically symmetric ionosphere was developed with sufficient completeness as early as in the 1920-1940's by Appleton, Ratcliffe, Beynon, Booker, Martyn, and others. This theory is presented in detail in the well-known monographs by Ginzburg (1967), Bremmer (1946), and Budden (1961). Based on this theory, detailed methods for the calculation of radio paths, determination of field amplitude, and interpretation of vertical and oblique ionograms have been developed. All these methods are well-known and widely used in practice, see monographs by Al'pert (1974), Shchukin (1940), and Davies (1969). An altogether different situation takes place in the case of very long-dis tance multihop and around-the-world propagation.
Download or read book Artificial Ionospheric Disturbances Caused by Powerful Radio Waves written by M. C. Lee and published by . This book was released on 1984 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Artificial ionospheric disturbances evidenced as fluctuations in plasma density and geomagnetic field can be caused by powerful radio waves with a broad frequency band ranging from a few KHz to several GHz. The filamentation instability of radio waves can produce both large-scale plasma density fluctuations and large-scale geomagnetic field fluctuations simultaneously. The excitation of this instability is examined in the VLF wave injection experiments, the envisioned MF ionospheric heating experiments, the HF ionospheric heating experiments and the conceptualized Solar Power Satellite project. Significant geomagnetic field fluctuations with magnitudes even comparable to those observed in magnetospheric (sub)storms can be excited in all of the cases investigated. Particle precipitation and airglow enhancement are expected to be the concomitant ionospheric effects associated with the wave-induced geomagnetic field fluctuations.
Download or read book Ionospheric Disturbances and Their Influence on Radio Communications written by Li︠u︡dmila Nikolaevna Li︠a︡khova and published by . This book was released on 1973 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Articles on ionospheric disturbances, and techniques for predicting condition of ionosphere for planning radio communication.
Download or read book Ionospheric Disturbances and Their Effects on the Propagation of Hf Electromagnetic Waves written by Chaio-Min Chu and published by . This book was released on 1964 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is concerned with the effect of ionospheric disturbances on HF radio waves whose propagation path is at a large distance from the source of the disturbance. The perturbation of the HF radio waves is assumed to be due to mechanical waves propagating in the atmosphere. The macroscopic equations governing the propagation of mechanical waves in the atmosphere, including the effects of viscosity and thermal conductivity, are developed. A simple model of the atmosphere is proposed and a technique, suitable for numerical analysis, is developed for determining the various modes propagating. The effect of the earth's magnetic field on the propagation of mechanical waves is evaluated and it is concluded that this effect is small. The modification of the disturbance due to the presence of charged particles is discussed in conjunction with a comparison of the microscopic and macroscopic formulation of the equations of motion. An idealized description of the source is given in the appendix and some solutions to some simple problems are discussed. (Author).
Download or read book Long Distance Propagation of HF Radio Waves written by Alexander V. Gurevich and published by Springer. This book was released on 1985 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of very long-distance and around-the-world propagation of HF radio waves becomes more urgent in connection with the problems of long distance ground-based radio communications, communications with space crafts and satellites, satellite-to-satellite communications, around-the-world radar scanning, around-the-world sounding of the ionosphere, etc. At pre sent, these investigations have acquired particular interest because transmit ters which make it possible to intentionally modify the ionospheric properties by powerful radio waves have become available. In the case of radio wave propagation over comparatively small distances (about 3000 - 5000 km, one - two hops), in a first approximation, the iono sphere can be considered homogeneous in the horizontal direction. The radio wave propagation theory in a horizontally-homogeneous, i. e. , spherically symmetric ionosphere was developed with sufficient completeness as early as in the 1920-1940's by Appleton, Ratcliffe, Beynon, Booker, Martyn, and others. This theory is presented in detail in the well-known monographs by Ginzburg (1967), Bremmer (1946), and Budden (1961). Based on this theory, detailed methods for the calculation of radio paths, determination of field amplitude, and interpretation of vertical and oblique ionograms have been developed. All these methods are well-known and widely used in practice, see monographs by Al'pert (1974), Shchukin (1940), and Davies (1969). An altogether different situation takes place in the case of very long-dis tance multihop and around-the-world propagation.
Download or read book Characterization of Propagation and Communication Properties of the Natural and Artificially Disturbed Ionosphere written by Bodo W. Reinisch and published by . This book was released on 1995 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hf Communication Effects Frequency Dispersion and Doppler Shift written by R. A. Shepherd and published by . This book was released on 1965 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: This effort was part of a program of research to determine the effects of high-altitude nuclear explosions on HF radio communications, using naturally occurring disturbances to simulate nuclear distrubances. Phase-stable transmissions at 7.366 Mc over a transauroral path from Thule, Greenland and over a mid-latitude path from Fort Monmouth, New Jersey were received at the SRI field site near Palo Alto, California. Both of these paths were paralleled by step-frequency oblique-incidence ionospheric sounders. Power spectra of the received CW signals were computed, enabling the identification of individual ionospheric modes by their separation in Doppler shift. Examples of power spectra of simple and of more complex mode structures, including off-path modes, are given. Statistics of the frequency dispersion and the Doppler shifts of the Thule and Fort Monmouth signals are compiled for selected data in February, March, and June, 1964. Comparisons show that while Doppler shifts for the two paths are similar in magnitude, the frequency dispersion of signals on the transauroral path is about ten times as great as that on the mid-latitude path. (Author).
Download or read book Physics Briefs written by and published by . This book was released on 1992 with total page 1156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Geophysics and Space Environments written by U.S. Air Force Geophysics Laboratory and published by . This book was released on 1985 with total page 1066 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Extreme Events in Geospace written by Natalia Buzulukova and published by Elsevier. This book was released on 2017-12-01 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extreme Events in Geospace: Origins, Predictability, and Consequences helps deepen the understanding, description, and forecasting of the complex and inter-related phenomena of extreme space weather events. Composed of chapters written by representatives from many different institutions and fields of space research, the book offers discussions ranging from definitions and historical knowledge to operational issues and methods of analysis. Given that extremes in ionizing radiation, ionospheric irregularities, and geomagnetically induced currents may have the potential to disrupt our technologies or pose danger to human health, it is increasingly important to synthesize the information available on not only those consequences but also the origins and predictability of such events. Extreme Events in Geospace: Origins, Predictability, and Consequences is a valuable source for providing the latest research for geophysicists and space weather scientists, as well as industries impacted by space weather events, including GNSS satellites and radio communication, power grids, aviation, and human spaceflight. The list of first/second authors includes M. Hapgood, N. Gopalswamy, K.D. Leka, G. Barnes, Yu. Yermolaev, P. Riley, S. Sharma, G. Lakhina, B. Tsurutani, C. Ngwira, A. Pulkkinen, J. Love, P. Bedrosian, N. Buzulukova, M. Sitnov, W. Denig, M. Panasyuk, R. Hajra, D. Ferguson, S. Lai, L. Narici, K. Tobiska, G. Gapirov, A. Mannucci, T. Fuller-Rowell, X. Yue, G. Crowley, R. Redmon, V. Airapetian, D. Boteler, M. MacAlester, S. Worman, D. Neudegg, and M. Ishii. Helps to define extremes in space weather and describes existing methods of analysis Discusses current scientific understanding of these events and outlines future challenges Considers the ways in which space weather may affect daily life Demonstrates deep connections between astrophysics, heliophysics, and space weather applications, including a discussion of extreme space weather events from the past Examines national and space policy issues concerning space weather in Australia, Canada, Japan, the United Kingdom, and the United States
