RADAR SCATTERING FROM A PLANE PARALLEL TURBULENT PLASMA SLAB WITH STEP FUNCTION FLUCTUATIONS OF ELECTRON DENSITY.
INSTITUTE FOR DEFENSE ANALYSES ARLINGTON VA SCIENCE AND TECHNOLOGY DIV
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A deterministic method of calculating radar propagation through a turbulent plasma is developed which involves the exact solution to the wave propagation equation through a slab in which the dielectric constant can vary randomly, repeated for an ensemble of slabs having common, prescribed statistical properties. The method is applied to the case of a plant wave normally incident upon an infinite plane parallel slab which, when unperturbed, is homogeneous. The electron density is perturbed by step function fluctuations which alternately increase or decrease the mean density by an equal amount. The lengths of the step function fluctuations have an exponential probability density. It is found that for the cases studied underdense plasma an ensemble of approximately 600 profiles is required in order to obtain meaningful averages. The mean reflection coefficients are compared with results obtained using the first order Born approximation, and the agreement is satisfactory in those cases for which the Born approximation is expected to be valid. The most significant departures from the Born approximation occur for low values of collision frequencyangular frequency of incident radiation and for high values of the root mean square electron density fluctuations. The reflection coefficient in the Born approximation is also derived for a general distribution of step function fluctuation lengths in a slab of finite thickness, and relaxation times are reviewed for the wakes of reentry vehicles. Author
- Active and Passive Radar Detection and Equipment
- Radiofrequency Wave Propagation