Electrodynamic Coupling Between Inertial Scale Alfven Waves and the High-latitude Auroral Ionosphere

English Abstract:

Small scale inertial Alfven waves (IAWs) can accelerate auroral electrons and are considered to be an important part of energy coupling between the magnetosphere and high latitude ionosphere. The coupling of IAWs with the ionosphere is affected by wave and background precipitation, heating due to wave and convection electric fields, and strong vertical nonuniformity of the bottom layers of the ionosphere. We have developed a comprehensive two-dimensional numerical model of the coupled magnetosphere and ionosphere that includes these effects. The model considers torsional Alfven waves in the presence of an externally imposed convection electric field, chemical reactions between ions and neutrals, various cooling and heating processes, and a parametric model of electron precipitation. The model’s spatial resolution in the E-layer can be as fine as tens of meters in the horizontal direction, and hundreds of meters in the vertical direction. We present applications of the model that are designed to understand reflection of waves with short transverse wavelength from the ionosphere, formation of ion upflows, feedback instabilities, and emission of Alfven waves by convecting plasma nonuniformities in the E-layer. The results are compared with observations from the Canadian ePOP satellite, and ground-based instruments of the GO-Canada observatory.