摘要:

The propagation of electromagnetic waves in inhomogeneous magnetoactive plasmas is studied. In particular, the so‐called extraordinary mode is considered. The starting point is the Fuchsian equation with four singular points: Heun's equation. Transformations are developed that transform Heun's equation into a Helmholtz equation. In this way, refractive index profiles accommodating a local resonance are generated. These refractive index profiles are connected with plasma density profiles through the dispersion relation for the extraordinary mode. The thus generated plasma density profiles contain a number of adjustable parameter

ISSN:0048-6604    

DOI:10.1029/RS015i001p00095

年代:1980

数据来源: WILEY

摘要:

An analytical framework to aid in the interpretation and prediction of synthetic aperture radar (SAR) images of the ocean is developed. Using stationary phase integration, explicit results are derived for high‐resolution images including the cross‐section modulation on the ocean and the weighting by the curvature of the phase distortion introduced by the wave motion into the backscattered fields. The general formulation demonstrates that SAR images of the ocean are a ‘map’ of the stationary points on the surface as interpreted by SAR. The general formulation is applied to predict the SAR image of a simple two‐scale ocean model using Bragg scattering. This work suggests that image formation of the ocean is due to the amplitude process for light winds (large modulations) and by the phase distortion process for high wind speeds (small modulations). Numerical results are obtained for the stationary points of our simple ocean model, and for the first time an actual SAR image of the ocean is predicted. Inherent in this formulation also is the wave number distortion of the dominant wave of the ocean if its phase speed is not negligible compared to the radar platform

ISSN:0048-6604    

DOI:10.1029/RS015i001p00105

年代:1980

数据来源: WILEY

摘要:

By making measurements of the scintillations of the 137‐MHz beacon of ATS 3 at three sites along the 70°W meridian, it was possible to amass a data bank sufficient to obtain empirical analytical formulas of average scintillation at subauroral and auroral latitudes. The data base consisting of 15‐min scintillation indices of 3–7 years of observations from Sagamore Hill, Massachusetts, Goose Bay, Labrador, and Narssarssuaq, Greenland, has been presented and discussed in a companion paper. Forcing functions for the empirical formulations are time of day, day of the year, magnetic index, and solar flux. The limitations of the data are outlined including single frequency of observations and the problem of limited excursion of scintillations. Corrections are given for geometrical effects using varying irregularity configur

ISSN:0048-6604    

DOI:10.1029/RS015i001p00115

年代:1980

数据来源: WILEY

摘要:

An expository analysis of electromagnetic induction in anN‐layered half space is presented. The objective is to develop general expressions for the surface impedance matrix at the air/earth boundary that exhibit the dependence on the source field configuration. The justification for ignoring this dependence is give

ISSN:0048-6604    

DOI:10.1029/RS015i001p00129

年代:1980

数据来源: WILEY

摘要:

A new multimode horn composed of a corrugated guide and a smooth‐walled guide with changing flare angles has been achieved. It not only has good electrical performance for both bands (at 4 and 6 GHz) used in satellite communications, but it also has advantages in production and application to engineering because of the small dimension of its length and its very short corrugated sectio

ISSN:0048-6604    

DOI:10.1029/RS015i001p00135

年代:1980

数据来源: WILEY

ISSN:0048-6604    

DOI:10.1029/RS015i001p00143

年代:1980

数据来源: WILEY