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arXiv · 2606.07566

Evolution of Coronal Mass Ejection Properties through Superposed Epoch Analysis from 0.2 to 2.2 au

Yakub Olufadi·Nada Al-Haddad·Florian Regnault·Noé Lugaz·Bin Zhuang·Charles J. Farrugia·Christian Möstl·Emma E. Davies·Eva Weiler
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Abstract

Coronal mass ejections (CMEs) are explosive and energetic events consisting of strong magnetic structures erupting from the solar corona. We use superposed epoch analysis to investigate the general properties of CMEs as measured {\it in situ} from 0.2 to 2.2 au based on over 1600 events obtained from the HELIO4CAST catalog. We examine the dependence of the CME global properties on solar cycle phase, and compare the CME parameters derived in the active phase (AP) with the quiet phase (QP). Our findings show that during the AP of the solar cycle, the occurring CMEs are faster and have stronger magnetic field strength than during the QP, which has denser but weaker magnetic strength. These differences in magnetic field strength and density remain even when controlling for the speed. This may indicate that the enhanced profiles observed during the AP are not only a consequence of the CME propagation speed but may also reflect intrinsic differences in the eruption mechanism during different solar cycle phases. We also study how the magnetic field strength and components of the CME magnetic ejecta (ME) structure evolve with heliocentric distance. We find that the toroidal and poloidal ME magnetic field components have a similar power law decrease with distance, indicating a comparable expansion behavior of CMEs in these dimensions. We further quantify the CME magnetic field asymmetry %(often associated with CME aging) using the front-to-rear ratio of the toroidal component across heliocentric distance and find evidence of an increase of this ratio with heliocentric distance.

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Yakub Olufadi, Nada Al-Haddad, Florian Regnault, Noé Lugaz, Bin Zhuang, Charles J. Farrugia, Christian Möstl, Emma E. Davies, Eva Weiler. 2026-05-25. Evolution of Coronal Mass Ejection Properties through Superposed Epoch Analysis from 0.2 to 2.2 au. https://arxiv.org/abs/2606.07566

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