Study of Doppler reflectometry capability to determine the perpendicular velocity and the k-spectrum of the density fluctuations using a 2D full-wave code

The capability of Doppler reflectometry to determine the perpendicular velocity and the perpendicular wave-number spectrum of the density fluctuations has been studied using a two-dimensional full-wave code. The numerical results show that the perpendicular velocity of the density fluctuations can be obtained with high accuracy for broad ranges of antenna tilt angles, turbulence levels and radial correlation lengths of the density fluctuations. The diagnostic potential of Doppler reflectometry to determine the perpendicular wave-number spectrum of the density fluctuations depends on the reflectometer response at different probed wave numbers and different turbulence levels. A linear dependence between the scattered wave amplitude and the turbulence level has been found for low turbulence levels and short radial correlation lengths of the density fluctuations, whereas at high turbulence levels and/or large radial correlation lengths the relationship becomes non-linear. In addition, numerical results show that the reflectometer response depends only very slightly on the probed wave number