Precipitating electron energy spectra and auroralpower estimation by incoherent scatter radar with hightemporal resolution

Abstract

Electron precipitation to the high-latitude ionosphere is a key process in magnetosphere-ionosphere coupling and in the physics of the mesosphere-lower thermosphere region, because the precipitating electrons carry electric current, transfer energy from the magnetosphere to the ionosphere, ionize neutral atoms and molecules, cause optical auroral emissions, heat the electron gas, and change the ion composition. High-resolution observations are needed in studies of these phenomena, as the processes often take place in small spatial and temporal scales.Electron precipitation is quantitatively characterized by the energy distribution of the primary electrons. Electron acceleration processes in the magnetosphere that lead to different energy spectral shapes are discussed by Dombeck et al. (2018) andNewell et al. (2009). For a known differential energy flux, altitude profiles of ion production rate and auroral emission rates can be determined if the neutral atmospheric parameters are known (Fang et al., 2010;Rees, 1963).Indirect estimation of the differential energy flux from electron density altitude profiles observed with an incoherent scatter radar (ISR) is an efficient way to observe electron precipitation from ground (