Incoherent scatter measurements and inferred energy fluxes in the equatorial F-region ionosphere

Faraday rotation and incoherent scatter correlation function measurements made using the Jicamarca Radio Observatory are used to infer the electron density and the electron and ion temperature of the equatorial F-region ionosphere over an altitude range of 150 to 1035 km. The electron density profiles obtained from the Faraday rotation and the total backscattered power appear self-consistent and the peak density agrees with simultaneous ionosonde readings. Temperature measurements made using two different antenna pointing positions (3 and 6 degrees) are not consistent. The electron temperature obtained at 3 deg is less than the corresponding ion temperature during the night and during the day at altitudes where one would expect the two species to be in thermal equilibrium. Electron and ion temperatures obtained at 6 deg do appear equal at time when they are expected to be equal. Data taken at Jicamarca using an older version of this experimental technique using the 3 deg antenna position appear to show the same problem. An exhaustive study of potential systematic experimental errors fails to provide an explanation for the inconsistency. A new technique is used to obtain the neutral temperature profile, the electron-ion energy flux, and more accurate electron and ion temperatures. The electron, ion, and neutral temperature profiles obtained from the constrained least squares process are used to compute the electron-neutral energy flux and using a measured solar EUV spectrum, the energy flux form the photoelectrons to thermal electrons is computed. The sum of the electron-ion and electron-neutral energy fluxes is shown to be consistent with the photoelectron to thermal electron energy flux calculated using a solar spectrum obtained on a day with similar solar activity as the day when the incoherent scatter data were obtained