Validation of the magnetized ICME model with a multi-spacecradt study in Icarus

Coronal Mass Ejections (CMEs) are the main drivers of interplanetary shocks and space weather disturbances. Strong CMEs directed towards Earth can have a severe impact on our planet and their timely prediction can enable us to mitigate (part of) the damage they cause. One of the key parameters that determine the geo-effectiveness of a CME is its internal magnetic configuration.

The novel heliospheric wind and CME propagation model Icarus (Verbeke et al. 2022) which is implemented within the framework of MPI-AMRVAC (Xia et al., 2018) introduces new capabilities for better and faster space weather forecasts. Advanced numerical techniques, such as solution adaptive mesh refinement (AMR) and radial grid stretching are implemented. The different refinement and coarsening conditions and thresholds are controlled by the user. These techniques result in optimized computer memory usage and a significant execution speed-up, which is crucial for forecasting purposes. 

In this study we validate a new magnetized CME model in Icarus by simulating  interplanetary coronal mass ejections (ICMEs).  We chose particular CME events observed at different radial distances from the Sun by MESSENGER and ACE. We aim to model two CME events, to examine the capabilities of the model in different configurations. We identify the originating active region for the CME of interest, reconstruct its characteristic parameters and initiate the CME propagation inside Icarus with a spheromak CME model. We focus on estimating the accuracy of the arrival time, the shock strength and the magnetic field components of the CME model in Icarus. Using observations of different satellites we can track the propagation of the CMEs in the heliospheric domain and assess the accuracy of the model at different locations.

Different AMR criteria are used to achieve higher spatial resolutions at propagating shock fronts and in the interiors of the ICMEs. This way the complex structure of the magnetic field and the deformation and (plasma and magnetic flux) erosion can be simulated with higher accuracy due to the advantage of AMR. Higher resolution is especially important for the spheromak model, because the internal magnetic field configuration affects the CME evolution and its interaction with the magnetized heliospheric wind significantly. We assess the capabilities of AMR at different locations in Icarus. Finally, the obtained synthetic time-series of plasma quantities at different satellite locations are compared to the available observational data. As a result, Icarus allows us to model CMEs with higher accuracy, yet efficiently.

TB acknowledges support from the European Union’s Horizon 2020 research and innovation program under No 870405 (EUHFORIA 2.0) and the ESA project “Heliospheric modeling techniques” (Contact No. 4000133080/20/NL/CRS).