Statistical data from Alouette and Injun 3 on the average precipitation rate of electrons in the auroral zone as a function of energy are discussed with regard to the average absorption produced by the energy ranges 1#x2013;40 kev. and 40#x2013;250 kev. From the satellite data, it is found that the higher energy range for the primary electrons is the dominating one in producing absorption at riometer frequencies. From this follows that the majority of auroral absorption takes place below 90 km. altitude in the auroral zone.
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