a model for RF scattering from fieldaligned heaterinduced irregularities
Abstract
The paper presents a model for radio wave scattering from the ionospheric irregularities generated by the intense radio wave transmissions from the Platteville heater. The model is based upon the HFUHF radar backscatter observations for a physical description of the scattering medium and upon the theory of weak scattering (Born approximation) from anisotropic irregularities for mathematical development. According to the model, the electron density fluctuations responsible for radio wave scattering having an rms value of 1 to 1.5% are aligned along the earth's magnetic field and are distributed in a diffuse pancakeshaped volume of 15 km gaussian thickness vertically and of the size of the heater beam which is 100 km in gaussian diameter horizontally. At radio frequencies the irregularities within the disturbed volume are highly aspect sensitive and consequently only those scatterers which lie on the surface of specularity where a radar views transverse to the magnetic field count in contributing to the received signal. Model computations have been made of the scattering cross sections for monostatic as well as bistatic radar configurations and they are found to be in good agreement with the observations. The radar cross section at a given frequency for bistatic geometry is substantially greater than that for monostatic geometry, all else being equal. Finally, it is shown that the width of the scatterilluminated bands on the ground is set primarily by the finite dimensions of the scattering volume rather than by the finite aspect sensitivity of the individual scatterers.
 Publication:

Radio Science
 Pub Date:
 November 1974
 DOI:
 10.1029/RS009i011p00987
 Bibcode:
 1974RaSc....9..987R
 Keywords:

 Atmospheric Models;
 Geomagnetism;
 Ionospheric Disturbances;
 Ionospheric Heating;
 Backscattering;
 Computerized Simulation;
 Electron Density Profiles;
 Ionospheric Propagation;
 Lines Of Force;
 Mathematical Models;
 Radar Scattering;
 Radio Scattering