The investigators will perform numerical modeling of the upper atmosphere using the National Center for Atmospheric Research (NCAR) thermosphere-ionosphere-electrodynamics general circulation model (TIEGCM). The major science focus is to quantify the role of electric fields and neutral winds in low latitude electrodynamics. This addresses one of the most fundamental question in thermospheric/ionospheric research: what is the relative importance of electric fields and neutral winds in determining the ionospheric densities, drifts, and structure? The question is particularly difficult because of the complex interaction between the neutral and ionized gases, involving much feedback and mutual adjustment. The TIEGCM is one of only three models worldwide that treat the coupled thermosphere-ionosphere system self-consistently. The investigators will use the TIEGCM to simulate the ionosphere and thermosphere for different seasons and five levels of solar activity. The model output consists of electric fields, conductivities, and neutral winds. A parametric study will be conducted to assess the relative importance of E region propagating tides and F region winds to the electrodynamics. Validation studies will be conducted using data from radars and optical instruments in Puerto Rico and Peru. The model results will be archived and made available to the scientific community
