Simultaneous observations of E-region coherent backscatter and electric field amplitude at F-region heights with the Millstone Hill UHF Radar



A combined coherent backscatter-incoherent scatter experiment with the Millstone Hill UHF radar provided simultaneous observations of electric field magnitude and coherent backscatter parameters on the same L shell. A carefully-designed geometry used sidelobe coherent contamination from two-stream irregularities at 110 km altitude, appearing at ranges corresponding to F-region altitudes in the main beam, in conjunction with simultaneous uncontaminated F-region observations of the equation image drift velocity in adjacent range gates. Both logarithmic coherent power and the magnitude of the coherent phase velocity Vph vary linearly with equation image. With the assumption that the coherent phase velocity is approximately the perturbed ion sound speed in the heated E region, we find an excellent agreement between the electron temperature inferred from Vph and previous incoherent-scatter results relating E-region Te to E. A maximum value of ∼3100 K has been found for such wave-induced E-region heating.