Auroral and photoelectron fluxes in cometary ionospheres

Abstract

Photoelectron and auroral electron fluxes in cometary ionospheres have been studied in detail using the analytical yield spectrum approach. The effects on photoelectron fluxes of cometocentric distance, solar zenith angle (using generalized Chapman function), and solar minimum and maximum conditions, on the assumption of local energy deposition, are determined. Energy loss to ambient electrons is accounted for. Auroral electron fluxes are calculated for monoenergetic and observed primary electron spectra. The results are compared with other theoretical works and good agreement is found. Auroral electrons make a larger contribution to the observed electron spectrum compared with the extreme ultraviolet-generated photoelectrons.