The Effect of Downward Electron Heat Flow and Electron Cooling Processes in the High- Latitude Ionosphere

The electron energy balance in the terrestrial ionosphere is affected by numerous local heating and cooling processes, as well as transport processes. The thermal electrons gain energy from photoelectrons, auroral electrons, hot thermal ions, and a downward flow of heat from high altitudes. The thermal electrons lose energy in elastic collisions with ions and neutrals (N2, O2, O, He, H), rotational excitation of N2 and O2, vibrational excitation of N2 and O2, excitation of the fine structure level of atomic oxygen, and electronic excitation of atomic oxygen. The transport processes include thermal conduction and thermoelectric heat flow. Recently, new cooling rates have been calculated that are substantially different from those in current use, which are more than thirty years old. We will present model simulations showing the impact these new cooling rates have on the electron temperatures and ion densities in the mid- and high-latitude ionosphere. Additionally, recent work based on DMSP satellite data has made it possible to estimate the proper values of the downward electron heat flow in the polar cap. This important parameter has typically been ignored in the past, due to a lack of measurements. We present the results of model simulations driven by the new estimates of the heat flow.