Sun-to-Earth evolution and space weather impact of the 21 April 2023 CME: validation of a space weather modeling framework

Abstract

The first severe geomagnetic storm of Solar Cycle 25 occurred on 23-24 April 2023, reaching a minimum Dst of -213 nT. Utilizing the state-of-the-art observational and modeling techniques, we investigate the Sun-to-Earth evolution of the coronal mass ejection (CME) that caused this severe geomagnetic storm. We use multi-wavelength and multi-vantage point remote sensing observations to constrain the near-Sun CME properties, which serve as input for the interplanetary flux rope simulator (INFROS) model to simulate the magnetic vectors of the ICME at 1 AU. Utilizing multi-point in situ observations of the ICME detected by both STEREO-A and Wind, we validate the INFROS model results at each spacecraft. We further couple INFROS with the Drag-Based Model (DBM) and empirical Dst prediction models, presenting a space weather modeling framework to estimate the intensity of the associated geomagnetic storm. Based on the remote sensing observations, we find that the CME eruption was associated with the partial eruption of a pre-existing filament structure, which led to an underestimation of the poloidal flux when determined using the post-eruption arcade (PEA) method. In contrast, empirical model-based estimations provide more accurate results on constraining the poloidal flux of the CME. The INFROS model successfully captures the magnetic structure of the ICME observed near Earth but fails to reproduce the trailing part of the flux rope as observed at STEREO-A, likely due to distortion caused by a following interacting high-speed stream. Validation of the space weather modeling framework with the observed SYM/H index for this event shows good agreement between the observed and predicted SYM/H profiles. These results highlight that the INFROS-based space weather modeling framework could serve as an operational space weather forecasting tool for predicting the intensity of geomagnetic storms.