Ionospheric Effects of the August 2017 Eclipse: Empirically Guided Modeling with Comparisons to Data

Understanding the dynamics of the ionosphere during the 2017 total solar eclipse requires numerical modeling, but requires special care and proper seeding to ensure that the model results accurately represent the rapidly varying physical processes and different geometries encountered along the eclipse path. Spatio-temporal variations in the intensity of the solar disc, the local magnetic field geometry, and the solar zenith angle produce unique behavior between sites, resulting in widespread differences in the eclipse effects as it traveled across the US. These differences are evident in Super Dual Auroral Radar Network (SuperDARN) radar data collected at Christmas Valley, Oregon and Fort Hayes, Kansas. Using high-resolution EUV images from the Solar Dynamics Observatory on the eclipse day we have implemented temporal and spatial dependent scaling of the ion photoproduction rates in the NRL-developed SAMI-3 global ionosphere model. We use the results to present direct comparisons between the model and radar data from the two SuperDARN sites, and we strive to interpret the results through comparisons with simulated HF ray propagation paths through the modeled ionosphere during the eclipse.