Predicting CMEs Using ELEvoHI With STEREO-HI Beacon Data

Coronal mass ejections (CMEs) are the main drivers of geomagnetic storms at Earth and are capable of impacting power grids on the planet’s surface as well as satellites in orbit. Developing models to accurately predict the arrival time and speed of CMEs is a necessary step towards ensuring that we are capable of providing advance warning to mitigate potential severe space weather effects. We use the Ellipse Evolution model based on Heliospheric Imager observations (ELEvoHl) to predict the arrival of CMEs at Earth using data from STEREO-A’s heliospheric imagers. The HI instruments provide both real-time, lower-quality beacon data as well as higher- quality science data which is downlinked to Earth with some delay. Issuing alerts for approaching CMEs before they arrive at Earth necessitates the utilization of real-time data. HI data for each event and data type is compiled into a time-elongation plot (Jmap) in which every CME’s trajectory is tracked manually. We predict the arrival time and speed of 10 Earth-directed CMEs from 2010 to 2020 using both science and beacon data with the ELEvoHI model and compare the results in terms of accuracy across both data types. We find that predictions made using beacon data are generally worse than those made using science data and give an outlook on possible future perspectives for improving the real-time prediction of CMEs.