Characterization of in situ ion drifts from the CREX-2 mission: implications for ionosphere-thermosphere coupling in the polar cusp

Ion–neutral coupling in the lower thermosphere–ionosphere (LTI, ~100–200 km) is greatest in the form of Joule heating and impacts atmospheric models and satellite drag. However, the LTI remains significantly underexplored observationally, with only ~60 hours of in situ measurements below 200 km, particularly within the dayside polar cusp. The Cusp Region EXperiment-2 (CREX-2) sounding rocket mission provides a unique opportunity to study the LTI within the cusp. The CREX-2 payload carried various plasma instruments including four Mini Plasma Imagers (MPIs), developed at the University of Calgary, designed to measure cold plasma ion drift velocity and temperatures at high temporal and spatial resolution. In this presentation we describe efforts to estimate the bulk ion drift velocity from the MPI data, along with the measurement uncertainty, to explore the momentum coupling of the ionosphere with the thermosphere below altitudes of 200 km in the dayside cusp.