Inductive-Dynamic Simulation on Locations of Energy Input to and Deposition in the Ionosphere-Thermospher

Abstract:

Recent observations of the net Poynting flux deposition to the ionosphere showed that the strongest energy input from the magnetosphere is in the polar cap where the plasma flow speed is high and not where the flow reverses, implying that the field-aligned current is not the primary agent of the energy transfer and that other physical progresses are at play. In this study we assess locations of the energy transfer and deposition by a simulation conducted with a self-consistent inductive-dynamic (including self-consistent solutions of Faraday's law and retaining inertia terms in the plasma momentum equations) ionosphere-thermosphere model. In a 2-D global geometry (dawn-dusk meridian plane), we solve the multifluid-collisional-Hall MHD equations including photochemistry. The preliminary simulation results demonstrate propagation and evolution of the field-aligned currents and the dynamic processes of the formation of the ionospheric Pedersen currents. By comparing locations of the field-aligned currents and ionosphere/thermosphere heating driven by the magnetospheric convection we show that the energy input to the IT system and the energy dissipation occurs in the polar cap instead of regions where the field-aligned currents reside. The implication of these results is that the field-aligned currents are not the primary agent of the energy transfer from the magnetosphere to the IT system.