Combining HAFv2 Model Simulations With SMEI Images to Improve ICME forecasts and Interpretations of Observations

The Solar Mass Ejection Imager (SMEI) provides important observations of the propagation and evolution of Interplanetary Coronal Mass Ejections (ICMEs). These measurements contribute to understanding the dynamics of ICMEs and their interaction with the background solar wind and IMF. In this study, we investigated whether the SMEI instrument could be used to track ICMEs en route to Earth and provide mid- course corrections to forecasts of their arrival times. We also investigated whether solar wind forecasts of Thompson Scatter brightness could be used to interpret observations of ICMEs by heliospheric imagers such as SMEI. We used the Hakamada-Akasofu-Fry Version 2 (HAFv2) 3D solar wind model to compute brightness skymaps at times corresponding to SMEI observations of ICMEs. We then compared the synthetic all-sky maps produced by HAFv2 with the SMEI image frames and analyzed the results. We found that more timely observations by heliospheric imagers such as SMEI would enable significant improvements in operational space weather forecasting skill. However, ICME observations and simulations are complementary, and combining them improves both the accuracy of forecasts and the interpretation of observations.