Validation of EUHFORIA cone and spheromak coronal mass ejection models

¹ Solar-Terrestrial Centre of Excellence – SIDC, Royal Observatory of Belgium, Avenue Circulaire 3, 1180 Brussels, Belgium
² CmPA/Department of Mathematics, KU Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium
³ NASA Goddard Space Flight Center, Greenbelt, MD, USA
⁴ Institute of Geodynamics of the Romanian Academy, Bucharest, Romania
⁵ Department of Physics, University of Helsinki, PO Box 64 00014 Helsinki, Finland
⁶ Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany
⁷ Blackett Laboratory, Imperial College London, London SW7 2AZ, UK
⁸ Institute of Physics, University of Maria Curie-Skłodowska, Lublin, Poland

Received: 7 February 2024
Accepted: 20 May 2024

Abstract

Aims. We present validation results for calculations of arrival times and geomagnetic impact of coronal mass ejections (CMEs) using the cone and spheromak CME models implemented in EUropean Heliospheric FORecasting Information Asset (EUHFORIA). Validating numerical models is crucial for ensuring their accuracy and performance with respect to real data.

Methods. We compared CME plasma and magnetic field signatures measured in situ by satellites at the L1 point with the simulation output of EUHFORIA. The validation of this model was carried out using two datasets in order to ensure a comprehensive evaluation. The first dataset focuses on 16 CMEs that arrived at Earth, offering specific insights into the model’s accuracy in predicting arrival time and geomagnetic impact. Meanwhile, the second dataset encompasses all CMEs observed over eight months within Solar Cycle 24, regardless of whether or not they arrived at Earth, covering periods of both solar minimum and maximum activity. This second dataset enables a more comprehensive evaluation of the model’s predictive precision in term of CME arrivals and misses.

Results. Our results show that EUHFORIA provides good estimates in terms of arrival times, with root mean square error (RMSE) values of 9 hours. Regarding the number of correctly predicted ICME arrivals and misses, we find a 75% probability of detection in a 12 hour time window and 100% probability of detection in a 24 hour time window. The geomagnetic impact forecasts measured by the K_p index provide different degrees of accuracy ranging from 31% to 69%. These results validate the use of cone and spheromak CMEs for real-time space weather forecasting.