Extreme dominance of Earth-origin heavy ions in the intense ring current near the Earth during the May 2024 super geomagnetic storm
Naritoshi Kitamura, Kazuhiro Yamamoto, Shoichiro Yokota, Satoshi Kasahara, Ayako Matsuoka, Kazushi Asamura, Yusuke Ebihara, Lynn M. Kistler, Kunihiro Keika, Atsuki Shinbori, Tomoaki Hori, Yoshizumi Miyoshi, Akimasa Ieda, Chae-Woo Jun, Mariko Teramoto, Masahito Nosé, Masafumi Hirahara, Kanako Seki, Nana Higashio, Iku ShinoharaSuper geomagnetic storms are characterized by extreme intensification of the ring current in near-Earth space. The origin of the ions that carry the ring current is key to understanding its development. In situ measurements of ring current ions by the Arase satellite demonstrate an unprecedented dominance of heavy ions originating from the Earth during the May 2024 super geomagnetic storm, despite the high solar wind density. The solar wind, another expected source of ions, contributes little to the energy density of the ring current. This observational evidence highlights the critical role of ion supply processes from the Earth and transport in the magnetosphere in developing the ring current for the super geomagnetic storm. Furthermore, the super-intense ring current penetrated close to the Earth, strongly deforming the local geomagnetic field and driving unusual outward transport of electrons, which led to the loss of radiation belt electrons from the near-Earth region.