Measuring F-region ion-neutral coupling in response to increases in auroral precipitation

Neutral winds are a key factor in the dynamics of the ionosphere-thermosphere system. Previous observations have shown neutral and ion flows are strongly coupled during periods of auroral activity when ion drag forcing can become the dominant force driving neutral wind flow. This is primarily due to increases in ion density due to enhanced particle precipitation as well as associated increases the strength of ion convection. Due to this strong coupling, numerical simulations of neutral dynamics have difficulty reproducing neutral wind observations when they are driven by modeled precipitation and modeled convection. It is therefore desirable whenever possible to have concurrent coincident measurements of auroral precipitation and ion convection. Recent advancements in high-resolution fitting of SuperDARN ion convection data have enabled the generation of steady maps of ion drifts over Alaska, coinciding with several optics sites. Available optical instruments include a digital all-sky imager and a meridian-scanning photometer, both of which provide measurements of auroral intensity on several wavelengths. Also present is a scanning Doppler imager, which can measure thermospheric winds and temperatures, including at both E- and F-region altitudes, the latter of which measures similar altitudes to SuperDARN, allowing for direct comparisons of ion and neutral velocities over a wide field and for long periods throughout a night. In this study, we combine these data sets to present three case studies that show significant correlation between increases in F-region precipitation and enhancements in ion-neutral coupling in the evening sector. We investigate the time scales over which the coupling takes place and compare our findings to previous measurements.