Electron Energy Interplay in the Geomagnetic Trap Below the Auroral Acceleration Region.

This publication addresses the collisional superthermal electron dynamics below the auroral acceleration region (AAR). This region is the portion of an auroral field line with a field‐aligned electric field that leads to the formation of precipitating monoenergetic keV electron fluxes that produce the discrete auroral displays observable from the ground. It is assumed that these precipitating electron fluxes are monoenergetic and accelerated through a potential drop, V, such that these electrons are peaked at an energy E0 = eV, where e is the electron charge. Monoenergetic electrons precipitating into the upper atmosphere degrade to lower energies via many different collisional processes and produce the secondary electron population with energies of 10–100s eV which escapes back to magnetospheric altitudes and becomes geomagnetically trapped between the AAR and the upper ionosphere. The secondary electrons in this geomagnetic trap transfer energy via elastic Coulomb collisions to the thermal electrons. That energy is then returned to the topside ionosphere as heat flux carried by the electron thermal conduction which is essential to maintaining the topside electron temperature. Key Points: Superthermal electron (SE) dynamics in the geomagnetic trap below the AAR is consideredHow SE distribution function evolve in response to the existence of geomagnetic trap is discussedThe SE energy interplay in the geomagnetic trap and the formation downward energy fluxes are considered [ABSTRACT FROM AUTHOR]