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CME Magnetic Structure and IMF Preconditioning Affecting SEP Transport

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journal contribution
posted on 25.08.2021, 10:01 by Erika Palmerio, Emilia KJ Kilpua, Olivier Witasse, David Barnes, Beatriz Sánchez-Cano, Andreas J Weiss, Teresa Nieves-Chinchilla, Christian Möstl, Lan K Jian, Marilena Mierla, Andrei N Zhukov, Jingnan Guo, Luciano Rodriguez, Patrick J Lowrance, Alexey Isavnin, Lucile Turc, Yoshifumi Futaana, Mats Holmström
Coronal mass ejections (CMEs) and solar energetic particles (SEPs) are two phenomena that can cause severe space weather effects throughout the heliosphere. The evolution of CMEs, especially in terms of their magnetic structure, and the configuration of the interplanetary magnetic field (IMF) that influences the transport of SEPs are currently areas of active research. These two aspects are not necessarily independent of each other, especially during solar maximum when multiple eruptive events can occur close in time. Accordingly, we present the analysis of a CME that erupted on 2012 May 11 (SOL2012-05-11) and an SEP event following an eruption that took place on 2012 May 17 (SOL2012-05-17). After observing the May 11 CME using remote-sensing data from three viewpoints, we evaluate its propagation through interplanetary space using several models. Then, we analyse in-situ measurements from five predicted impact locations (Venus, Earth, the Spitzer Space Telescope, the Mars Science Laboratory en route to Mars, and Mars) in order to search for CME signatures. We find that all in-situ locations detect signatures of an SEP event, which we trace back to the May 17 eruption. These findings suggest that the May 11 CME provided a direct magnetic connectivity for the efficient transport of SEPs. We discuss the space weather implications of CME evolution, regarding in particular its magnetic structure, and CME-driven IMF preconditioning that facilitates SEP transport. Finally, this work remarks the importance of using data from multiple spacecraft, even those that do not include space weather research as their primary objective.


Doctoral Programme in Particle Physics and Universe Sciences at the University of Helsinki Emil Aaltosen Säätiö (Emil Aaltonen Foundation) NASA Living With a Star Jack Eddy Postdoctoral Fellowship Program. Grant Number: NNX16AK22G EC | H2020 | H2020 Priority Excellent Science | H2020 European Research Council (ERC). Grant Number: 724391 UK-STFC. Grant Number: ST/S000429/1 Austrian Science Fund (FWF). Grant Number: P31521-N27 European Space Agency (ESA) Belgian Federal Science Policy Office (BELSPO) Strategic Priority Program of the Chinese Academy of Sciences. Grant Number: XDB41000000,XDA15017300 CNSA pre-research Project on Civil Aerospace Technologies. Grant Number: D020104 Academy of Finland (Suomen Akatemia). Grant Number: 322544 Academy of Finland (Suomen Akatemia). Grant Number: 312390



Palmerio, E., Kilpua, E. K. J., Witasse, O., Barnes, D., Sánchez-Cano, B., Weiss, A. J., et al. (2021). CME magnetic structure and IMF preconditioning affecting SEP transport. Space Weather, 19, e2020SW002654.

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School of Physics and Astronomy


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Space Weather






American Geophysical Union (AGU), Wiley





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50 pages, 14 figures, 2 tables, accepted for publication in Space Weather



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