Quantitative description of electron precipitation during auroral absorption events in the morning/noon local-time sector

Flux-energy spectra of precipitating electrons are derived from electron de nsity profiles measured by the EISCAT radar during auroral absorption event s in the morning/noon local-time sector. The inversion technique uses effec tive recombination coefficient profiles computed on the basis of a previous ly validated theoretical model of the lower ionosphere. It is shown that fl ux-energy spectra for the energy range 30-200 keV are in reasonable agreeme nt with those derived for the same events using trapped flux-energy spectra from geosynchronous satellite data and a model for diffusion of trapped el ectrons into the loss cone by scattering on whistler waves. During individu al events, strongly varying precipitating fluxes are found to be due primar ily to varying pitch-angle diffusion. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.