Comprehensive analysis of CME-driven shocks observed by multi-spacecraft observations

In this study, we aim at analyzing coronal mass ejection (CME)-driven shocks, possibly observed by a constellation of satellites, at the solar source and in the inner heliosphere. We started with the analysis of the CME detected by STEREO-A, SOHO, Parker Solar Probe, and Solar Orbiter between 5 and 6 September 2022. In particular, thanks to the remote observations from Stereo-A, SOHO, and Parker Solar Probe it has been possible to reconstruct the shock wave both in 2D and 3D and to derive shock parameters, such as the compression ratio and the Mach numbers at its source. The analysis has been supported by in-situ observations in the inner heliosphere at different radial distances and longitudes by Solar Orbiter and Parker Solar Probe. It has been found that the shock wave is strong with a high compression ratio both at the source and when detected in the interplanetary space, while the Mach numbers tend to decrease due to a deceleration of the shock. The 3D reconstruction tool setup can be further applied to other CMEs detected by multiple spacecraft. In addition, an investigation on the high-energy protons accelerated at the shock wave has been carried out in order to infer their transport properties in the heliosphere, jointly with the shape of the differential proton energy spectrum. Such an analysis has also been performed for several interplanetary CMEs.
This study is achieved in the context of the research project “Data-based predictions of solar energetic particle arrival to the Earth” funded by the Italian Ministry of Research under the grant scheme PRIN-2022-PNRR.