Incoherent scatter radar spectrum distortions from intense auroral turbulence

The authors discuss two violations of the basic assumptions used in analyzing radar incoherent scatter data, (1) the assumption of homogeneity across the volume of space viewed by the radar, and (2) the assumption that there is no time variation of the parameters being probed by the radar during its averaging time. Violations of either of these assumptions can lead to strong bias in the interpreted plasma parameters. They present their arguments based on observations made by the EISCAT radar. Being able to understand the significance of such variations, or turbulence, is of value in correctly interpreting radar data, and also is of value in the study of such turbulent phenomena in the ionosphere. Other experiments have demonstrated the existence of large gradients in spatial structure within the ionosphere. In addition the ability to study time varying phenomena is of obvious value