Magnetic Structure and Propagation of Two Interacting CMEs From the Sun to Saturn

Erika Palmerio*, Teresa Nieves-Chinchilla, Emilia K.J. Kilpua, David Barnes, Andrei N. Zhukov, Lan K. Jian, Olivier Witasse, Gabrielle Provan, Chihiro Tao, Laurent Lamy, Thomas J. Bradley, M. Leila Mays, Christian Möstl, Elias Roussos, Yoshifumi Futaana, Adam Masters, Beatriz Sánchez-Cano

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


One of the grand challenges in heliophysics is the characterization of coronal mass ejection (CME) magnetic structure and evolution from eruption at the Sun through heliospheric propagation. At present, the main difficulties are related to the lack of direct measurements of the coronal magnetic fields and the lack of 3D in-situ measurements of the CME body in interplanetary space. Nevertheless, the evolution of a CME magnetic structure can be followed using a combination of multi-point remote-sensing observations and multi-spacecraft in-situ measurements as well as modeling. Accordingly, we present in this work the analysis of two CMEs that erupted from the Sun on April 28, 2012. We follow their eruption and early evolution using remote-sensing data, finding indications of CME–CME interaction, and then analyze their interplanetary counterpart(s) using in-situ measurements at Venus, Earth, and Saturn. We observe a seemingly single flux rope at all locations, but find possible signatures of interaction at Earth, where high-cadence plasma data are available. Reconstructions of the in-situ flux ropes provide almost identical results at Venus and Earth but show greater discrepancies at Saturn, suggesting that the CME was highly distorted and/or that further interaction with nearby solar wind structures took place before 10 AU. This work highlights the difficulties in connecting structures from the Sun to the outer heliosphere and demonstrates the importance of multi-spacecraft studies to achieve a deeper understanding of the magnetic configuration of CMEs.

Original languageEnglish
Article numbere2021JA029770
JournalJournal of Geophysical Research: Space Physics
Issue number11
Publication statusPublished - Nov 2021


  • coronal mass ejections
  • heliophysics
  • heliosphere
  • interplanetary magnetic field
  • solar wind

ASJC Scopus subject areas

  • Space and Planetary Science
  • Geophysics

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