Download or read book Propagation of Elf and Vlf Waves Below an Anisotropic Ionosphere with a Dipping Static Magnetic Field written by Janis Galejs and published by . This book was released on 1967 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fields of cylindrically curved ionosphere layers are approximated by exponential functions which consider the increase of the phase velocity and decrease of the attenuation rate with the altitude of the layers. Matrix multiplication techniques are applied to the treatment of multi-layer ionosphere models. The individual ionosphere layers are thin relative to the wavelength and the approximate field representations give in the limits of horizontal and radial static magnetic field results identical to those obtained using more accurate treatments of curvature effects. TM modes in the space between the earth and the ionosphere excite coupled TM and TE modes in the ionosphere layers, the presence of which are considered in an iterative solution of the modal equation. In the ELF range propagation parameters computed for the East to West (EW) and West to East (WE) directions differ most for dip angles of 15 to 30 degrees. In the VLF range propagation parameters may exhibit discontinuities for EW direction. The interference distance D of the two lower-wave guide modes is increased for propagation in the EW direction relative to propagation in WE direction provided that the electron density profiles exhibit sharp density gradients at heights in the range from 80 - 85 km. The desired propagation characteristics could not be produced in the presence of a nondipping static magnetic field or using smoothly varying electron density profiles. (Author).
Download or read book Propagation of Elf and Vlf Waves Below a Generally Anisotropic Ionosphere written by Janis Galejs and published by . This book was released on 1968 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mode analysis of ELF and VLF waves has been generalized to allow arbitrary directions of propagation below a curved stratified ionosphere with a dipping static magnetic field. In the ELF range, the propagation parameters are changed almost linearly with the azimuthal angle phi by varying the direction of propagation from East to West. In the VLF range, the phase velocity exhibits its maximum value for propagation in South and North direction; and minimum values occur for propagation towards West. Also, maximum attenuation rates occur for propagation towards West. Measured interference distances D of the two lowest wave-guide modes have been explained using nighttime ionosphere models which exhibit sharp density gradients in the height range from 80 to 85 km. (Author).
Download or read book Propagation of SLF ELF Electromagnetic Waves written by Weiyan Pan and published by Springer Science & Business Media. This book was released on 2013-10-12 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the SLF/ELF wave propagation, an important branch of electromagnetic theory. The SLF/ELF wave propagation theory is well applied in earthquake electromagnetic radiation, submarine communication, thunderstorm detection, and geophysical prospecting and diagnostics. The propagation of SLF/ELF electromagnetic waves is introduced in various media like the earth-ionospheric waveguide, ionospheric plasma, sea water, earth, and the boundary between two different media or the stratified media. Applications in the earthquake electromagnetic radiation and the submarine communications are also addressed. This book is intended for scientists and engineers in the fields of radio propagation and EM theory and applications. Prof. Pan is a professor at China Research Institute of Radiowave Propagation in Qingdao (China). Dr. Li is a professor at Zhejiang University in Hangzhou (China).
Download or read book Propagation of Vlf Waves Below an Anisotropic Stratified Ionosphere with a Transverse Static Magnetic Field written by Janis Galejs and published by . This book was released on 1966 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The surface impedance of a cylindrically stratified anisotropic ionosphere has been computed in the presence of a transverse static magnetic field without requiring explicit representations of the individual cylindrical wave functions in the lower ionospheric layers. The propagation parameters are determined from the usual transcendental modal equation which is solved starting out with an initial real solution dependent on the reactive part of the ionospheric surface impedance. The surface impedance computations are continued below the ionospheric boundary height and the impedance reflected to the ground level by the ionosphere is compared with the ground impedance. The accuracy of the modal equation is shown to be comparable to a few percent uncertainty of the ground impedance for low conductivity ground. The propagation parameters of the first three waveguide modes are calculated for a number of ionosphere models which include the recent D-region models of Deeks. For propagation in the east to west direction, the phase velocity of the second mode is shown to be discontinuous when the real part of the ionospheric reflection coefficient undergoes a sign change. (Author).
Download or read book Propagation of ELF and VLF Waves Near the Earth written by I︠A︡kov Lʹvovich Alʹpert and published by Springer. This book was released on 1970 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Terrestrial Propagation of Long Electromagnetic Waves written by Janis Galejs and published by Elsevier. This book was released on 2013-10-22 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Technical Abstract Bulletin written by Defense Documentation Center (U.S.) and published by . This book was released on 1967 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1968 with total page 1116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1968-03 with total page 926 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vlf Modes Below an Idealized Anisotropic Ionosphere written by J. Galejs and published by . This book was released on 1969 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cylindrical shell between the earth and a homogeneous or exponentially varying ionosphere model is excited by vertically or horizontally polarized line sources, and these fields are related to dipole fields in a spherical shell. Because of ionospheric anisotropy, the vertically polarized source excites also TM field components with wave numbers corresponding to TE modes; and a horizontally polarized source excites TE fields corresponding to TM modes, particularly for the higher frequencies at nighttime and for propagation towards west. Among the field components tangential to the ground surface, TM fields tend to dominate with the exception of TE modes at daytime and for lower frequencies also at night. TM modes dominate in the nighttime mode sum (or interference pattern) for propagation towards east, but the two lower TE modes contribute significantly if propagation is towards west. Simplified computational models which neglect the radial component of the earth's static magnetic field are justified under daytime conditions. At nighttime such calculations provide extreme changes in the attenuation rates and phase velocity variations, which are opposite to the ones observed with a dipping static magnetic field. The direction dependence of the phase velocity is eliminated by decreasing the strength of the static magnetic field. (Author).
Download or read book A model for propagation of ELF and VLF waves below naturally perturbed ionospheres written by J. Galejs and published by . This book was released on 1967 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A terrestrial propagation model is studied where the earth to ionosphere waveguide system is cylindrically stratified, the dip angle of the static magnetic field is assumed to be arbitrary and the waves propagate in East to West or West to East directions at a constant magnetic latitude. The profiles of ionospheric electronic density chosen for the numerical computations are representative of sudden ionospheric disturbances (SID), solar flares, auroral absorption or polar cap absorption (PCA) events. The resulting phase velocity and attenuation rates of ELF and VLF signals are compared with those computed under representative quiet daytime conditions. PCA events (which give the most dramatic effects) cause a lowering of the effective ionosphere; the resulting propagation is nearly isotropic and the phase velocities are decreased at ELF and increased at VLF. The attenuation rates are increased at ELF and also in the lower part of the VLF band. The propagation parameters are affected to a lesser degree by the other events: ionospheric density perturbations at heights below 60 km have more readily discernable effects at ELF, while the changes of the ionospheric density gradient at larger heights are observable at VLF. However, these differences are not uniquely distinguishable from propagation characteristics obtainable under quiet daytime conditions. (Author).
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1969 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Assembl e Pl ni re written by International Radio Consultative Committee and published by . This book was released on 1982 with total page 930 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recommendations and Reports of the CCIR 1978 written by International Radio Consultative Committee and published by . This book was released on 1978 with total page 1108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Documentation of Plasma Physics Pt 1 Experimental Plasma Physics and Theoretical Plasma Physics written by and published by . This book was released on 1968 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of Scientific and Industrial Reports written by and published by . This book was released on 1968 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1967 with total page 1186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
