Nature Communications (Jul 2023)

Direct evidence of substorm-related impulsive injections of electrons at Mercury

  • Sae Aizawa,
  • Yuki Harada,
  • Nicolas André,
  • Yoshifumi Saito,
  • Stas Barabash,
  • Dominique Delcourt,
  • Jean-André Sauvaud,
  • Alain Barthe,
  • Andréi Fedorov,
  • Emmanuel Penou,
  • Shoichiro Yokota,
  • Wataru Miyake,
  • Moa Persson,
  • Quentin Nénon,
  • Mathias Rojo,
  • Yoshifumi Futaana,
  • Kazushi Asamura,
  • Manabu Shimoyama,
  • Lina Z. Hadid,
  • Dominique Fontaine,
  • Bruno Katra,
  • Markus Fraenz,
  • Norbert Krupp,
  • Shoya Matsuda,
  • Go Murakami

DOI
https://doi.org/10.1038/s41467-023-39565-4
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 7

Abstract

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Abstract Mercury’s magnetosphere is known to involve fundamental processes releasing particles and energy like at Earth due to the solar wind interaction. The resulting cycle is however much faster and involves acceleration, transport, loss, and recycling of plasma. Direct experimental evidence for the roles of electrons during this cycle is however missing. Here we show that in-situ plasma observations obtained during BepiColombo’s first Mercury flyby reveal a compressed magnetosphere hosts of quasi-periodic fluctuations, including the original observation of dynamic phenomena in the post-midnight, southern magnetosphere. The energy-time dispersed electron enhancements support the occurrence of substorm-related, multiple, impulsive injections of electrons that ultimately precipitate onto its surface and induce X-ray fluorescence. These observations reveal that electron injections and subsequent energy-dependent drift now observed throughout Solar System is a universal mechanism that generates aurorae despite the differences in structure and dynamics of the planetary magnetospheres.