Numerical Solution of Full-wave Equation with Mode-coupling

Numerical Solution of Full-wave Equation with Mode-coupling
Author: Yuji Inoue
Publisher:
Total Pages: 50
Release: 1966
Genre: Electromagnetic waves
ISBN:

A new method for the numerical solution of the wave equation governing the propagation of electromagnetic waves in a horizontally stratified, inhomogeneous, anisotropic layer is described. The wave equation is a homogeneous set of four linear differential equations of the first order. In the computer calculation, all singularities of the wave equation are removed in practical cases and a proper step-size based on the gradients of the medium properties is programmed automatically. The multiplicative nature of the solutions facilitates the procedure. Modification of solutions from one height to another is expressed in explicit form on the assumption that the propagation tensor varies linearly with height in each step of integration. In the mathematical development, matrix operations are extensively used in order to achieve a general representation. Four independent solutions of the wave equation are derived. During an ordinary integration for an inhomogeneous medium, a degradation occurs inevitably in the degree of linear independence among special solutions. This cause is analyzed. To obtain a complete set of special solutions with good linear independence, a particular device is developed for general applications. This method has been programmed for computer calculation by an IBM 7090. The resultant wave fields and wave polarizations for the independent modes are shown for a model ionosphere. The resultant wave is described as a 'scrambling' of four characteristic waves. The 'scrambling' state is visualized at each height. (Author).

Numerical Solution of Wave Equations for Long Wavelength Radio Waves

Numerical Solution of Wave Equations for Long Wavelength Radio Waves
Author: Samuel Horowitz
Publisher:
Total Pages: 24
Release: 1971
Genre: Atmospheric models
ISBN:

The long wavelength reflection coefficients for a day and night horizontally stratified model ionosphere are calculated by integrating the governing differential equations. The wave fields inside the ionosphere and the group height are also illustrated. This is useful when the measured reflection or conversion coefficients show unexpected features and a detailed examination of these wave fields may lead to a physical insight of the origin of such features. The compute time is 200 horizontally stratified slabs per second on a CDC 6600. (Author).

Powerflux I

Powerflux I
Author: E. A. Lewis
Publisher:
Total Pages: 28
Release: 1975
Genre: Integral equations
ISBN:

A simple integral formulation is given for the radio wave power propagating between the curved earth and the ionosphere for the case of low frequency transmitters on the surface of the earth. By making assumptions about the vertical field profiles, the field strengths at arbitrary distances and altitudes can be estimated. Field strength versus distance predictions are compared with published mode and wave-hop calculations and with experimental data.

LF Transmitting Antennas for a Protected Null-zone Application

LF Transmitting Antennas for a Protected Null-zone Application
Author: John L. Heckscher
Publisher:
Total Pages: 56
Release: 1975
Genre: Antenna arrays
ISBN:

The suitability of two candidate LF transmitting arrays for a specific point-to-point communication link is assessed subject to a null zone requirement. Critical parameters are identified, and calculations are made based on both given and estimated parameters. Limitations of available information are discussed, and approaches are suggested for obtaining additional experimental data.

Rocket Investigations of the VLF Ionospheric Transmission Window

Rocket Investigations of the VLF Ionospheric Transmission Window
Author: Richard B. Harvey
Publisher:
Total Pages: 40
Release: 1973
Genre: Ionosphere
ISBN:

Receivers were flown in rockets from Eglin Air Force Base, Florida, Natal, Brazil, and Fort Churchill, Canada, to study the fields of very low frequency (VLF) waves propagating in the earth-ionosphere waveguide, and leaking through the ionosphere to altitudes of 500-600 km. Amplitude-height, group delay, and polarization profiles are given for signals from a number of ground based transmitters. A coherent propagation model is proposed and partially tested by calculating Doppler shifts. The model, extended with a full-wave computer program, allows wave-field profiles to be approximated theoretically. The extent to which some sample calculations agree with the observations is discussed. (Author).

Ionospheric Research in Support of Atmospheric Ionozation Effects

Ionospheric Research in Support of Atmospheric Ionozation Effects
Author: George J. Gassmann
Publisher:
Total Pages: 64
Release: 1968
Genre: Atmosphere, Upper
ISBN:

For the specific goal to control or predict man-made ionization effects the Defense Department has stimulated research in some areas and particularly in ionospheric physics. The results are reviewed with the implication that most of them are significant only within the larger pool of knowledge being produced by basic research. The review covers recent results gained by means of rockets and satellites on various atmospheric parameters and on the various particle inputs. Further, it reports on conjugate phenomena, on geographical features of particle influx and of electric fields and on progress in radio propagation measuring techniques. Finally, it reviews the observed effects on the ionosphere during the coordinated 12 November 1966 solar eclipse expedition. (Author).