Intense Magnetopause Erosion at Earth During the May 2024 Solar Storm
Abstract
Abstract Earth's main magnetic field forms the magnetosphere, shielding the planet from solar wind plasma. Southward interplanetary magnetic fields erode the magnetosphere, a process known as magnetopause erosion, allowing solar wind penetration close to the Earth. While magnetic reconnection is considered a key driver, the mechanism during super geomagnetic storms remains unclear due to limited in situ observations. Here, we report a magnetopause crossing by Arase at 4.96 R E during the May 2024 superstorm, one of the innermost magnetopause crossings ever detected by magnetospheric spacecraft. We observe an anomalous and global reduction in magnetic field intensity extending from the inner magnetosphere to the magnetopause, suggesting global weakening by magnetospheric currents. This weakened magnetic field is responsible for the enhanced magnetopause erosion.
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Authors: Kazuhiro Yamamoto, Yoshizumi Miyoshi, Naritoshi Kitamura, Rumi Nakamura, Atsuki Shinbori, Ayako Matsuoka, Mariko Teramoto, Shoichiro Yokota, Satoshi Kasahara, Kunihiro Keika, Tomoaki Hori, Kazushi Asamura, Y. Kazama, Shiang-Yu Wang, Sunny Wing-Yee Tam, Tzu-Fang Chang, B N Wang, Chae‐Woo Jun, Iku Shinohara
Institutions: The University of Osaka, The University of Tokyo, National Cheng Kung University, Kyung Hee University, Austrian Academy of Sciences, Academia Sinica, Japan Aerospace Exploration Agency, Institute of Astronomy and Astrophysics, Academia Sinica, Institute of Space and Astronautical Science, Kyushu Institute of Technology, Space Research Institute, Institute for Space-Earth Environmental Research, Nagoya University, Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University