A Monte-Carlo electron transport model to investigate the role of the magnetic field on the downward and upward electron fluxes, the brightness and the emitted power of auroral emissions.

The ratio between the upward and downward energy fluxes computed at the top of the atmosphere for the case without crustal magnetic field is of 0.1, while for typical topology of the magnetic field it could be as large as 0.3, and even 0.6 for the case of moderate value of the crustal magnetic field.

Simulations based on an ASPERA-3 measured auroral electron precipitation indicate that magnetic mirroring leads to an intensification of the energy flux carried by upward moving electrons– from about 20% in the absence of crustal magnetic field up to 33–78% when magnetic field is included depending on magnetic field topology.

Crustal magnetic field results in increase of the upward electron flux, and, consequently, in reduction of the total auroral brightness for given energy flux of precipitating electrons.