Electron production and loss rates in theFregion

Accurate measurements of the amount of Faraday rotation imposed on VHF telemetry transmissions from a geostationary satellite have been analyzed to study rates of production and loss of electrons in the F region of the ionosphere. The rate of photoionization of atomic oxygen, integrated with respect to height through the ionosphere, was determined at sunrise over Hawaii. The analysis also yielded the magnitude of the linear loss coefficient at an altitude of 300 km. The integrated rate of production of O+ ions at sunrise was used to deduce the total flux of solar EUV radiation in the 165–911 A wavelength range incident on the earth's atmosphere. Atomic oxygen photoionization rates and solar EUV flux values were obtained on a daily basis, and loss coefficients were obtained on a monthly average basis, over the 2-year period extending from September 1964 through August 1966. The integrated rate of production of O+ was found to average 1.7 × 109 ions/cm² sec at sunrise over Hawaii. The flux of solar EUV radiation incident on the atmosphere was found to average 4.5 × 1010photons/cm² sec. The loss coefficient averaged 1.4 × 10−5 sec−1 at an altitude of 300 km. No seasonal variation was observed in the integrated O+ production rate, but the loss coefficient had a winter-to-summer variation of about 2∶1.