Numerical simulation of fluctuation measurements by reflectometry

A full wave, one dimensional, model of the phase response of reflectometers to density fluctuations is presented. The model is based on obtaining numerical solutions to the electromagnetic wave equation in a turbulent dielectric medium using a differencing method. In order to test the accuracy of the model, its results are compared with analytic solutions of the wave equation. The model is used to determine the phase response of a single channel reflectometer and a two channel correlation reflectometer to density fluctuations. For the single channel device, it is concluded that it is only possible to obtain qualitative information on the density fluctuations. However, for the two channel correlation reflectometer it is shown that it is possible to determine, under certain conditions, the radial dispersion relation of the fluctuations and the radial correlation lengths. (author). 4 refs, 15 figs