Aizawa Sae, Harada Yuki, André Nicolas, Saito Yoshifumi, Barabash Stas, Delcourt Dominique, Sauvaud Jean-André, Barthe Alain, Fedorov Andréi, Penou Emmanuel, Yokota Shoichiro, Miyake Wataru, Persson Moa, Nénon Quentin, Rojo Mathias, Futaana Yoshifumi, Asamura Kazushi, Shimoyama Manabu, Hadid Lina Z, Fontaine Dominique, Katra Bruno, Fraenz Markus, Krupp Norbert, Matsuda Shoya, Murakami Go
IRAP, CNRS-UPS-CNES, Toulouse, France.
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan.
Nat Commun. 2023 Jul 18;14(1):4019. doi: 10.1038/s41467-023-39565-4.
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.
