The future of coherent radars in the study of E-region irregularities

It has become obvious that there is need for better time resolution and to measure and understand the spectral details better for coherent scatter radars especially for E-region studies. Two experimental improvements are suggested. The first is to transmit two pulses of different wave polarization which has the potential to improve time resolution by more than an order of magnitude or allow more accurate spectral measurements. Secondly, a third radar added to a dual system like STARE, allows clearer interpretation of the line-of-sight velocities measured. A understanding of the physics involved may lead to better use of these measurements to estimate both electron drift and the ion acoustic speed (which may then be used to estimate electron temperature). The spectral width has still to be interpreted, but may be associated with the refraction or twisting of the irregularities as they move in the electric field of larger scale perturbations. Finally as an exemple, the use of the auto-correlation function at long delays may provide a measurement of the velocity of the primary instability and thus be a significant parameter