Faraday rotation measurements using incoherent scatter

A complete description is given of the method used at the Jicamarca Radar Observatory to derive Faraday rotation information (and hence absolute electron density profiles that do not require subsequent normalization or correction for the effects of Te/4) from incoherent scatter data. Similar techniques which could be used at other observatories with radars not having the unusual properties of the Jicamarca radar are discussed. At temperate and polar latitudes the optimum frequencies for incoherent scatter Faraday measurements in most of the ionosphere are roughly 100–200 MHz. Somewhat higher frequencies should give acceptable daytime results, however. A slight modification of the Faraday measurement, used at Jicamarca to obtain the autocorrelation function of the scattered signal, is also briefly described.