Effects of the May 2024 Solar Storm on the Earth's Radiation Belts Observed by CALET on the International Space Station

Ficklin, A. W.; Bruno, A.; Blum, L.; Cannady, N.; Guzik, T. G.; Adriani, O.; Akaike, Y.; Asano, K.; Asaoka, Y.; Berti, E.; Betti, P.; Bigongiari, G.; Binns, W. R.; Bongi, M.; Brogi, P.; Castellini, G.; Checchia, C.; Cherry, M. L.; Collazuol, G.; De Nolfo, G. A.; Ebisawa, K.; Fuke, H.; Gonzi, S.; Hams, T.; Hibino, K.; Ichimura, M.; Israel, M. H.; Kasahara, K.; Kataoka, J.; Kataoka, R.; Katayose, Y.; Kato, C.; Kawanaka, N.; Kawakubo, Y.; Kobayashi, K.; Kohri, K.; Krawczynski, H. S.; Krizmanic, J. F.; Maestro, P.; Marrocchesi, P. S.; Mattiazzi, M.; Messineo, A. M.; Mitchell, J. W.; Miyake, S.; Moiseev, A. A.; Mori, M.; Mori, N.; Motz, H. M.; Munakata, K.; Nakahira, S.; Nishimura, J.; Negro, M.; Okuno, S.; Ormes, J. F.; Ozawa, S.; Pacini, L.; Papini, P.; Rauch, B. F.; Ricciarini, S. B.; Sakai, K.; Sakamoto, T.; Sasaki, M.; Shimizu, Y.; Shiomi, A.; Spillantini, P.; Stolzi, F.; Sugita, S.; Sulaj, A.; Takita, M.; Tamura, T.; Terasawa, T.; Torii, S.; Tsunesada, Y.; Uchihori, Y.; Vannuccini, E.; Wefel, J. P.; Yamaoka, K.; Yanagita, S.; Yoshida, A.; Yoshida, K.; Zober, W. V.

doi:10.22323/1.501.1293

The Calorimetric Electron Telescope (CALET), launched to the International Space Station in 2015, provides more than 9 years of continuous observation of the radiation environment at low Earth orbit. Using this dataset, we present 5 months of observations following the May 2024 solar storms and the effects they had on the radiation belts across three electron energy ranges (>1.5, >3.4, and >8.2MeV). We show that this event populated a long-lasting new structure of relativistic electrons extending to values of L shell below the slot region barrier of L = 2.8. Additionally, we observe the decay rates for this population as a function of energy and L shell to show the evolution of this structure over time.

Effects of the May 2024 Solar Storm on the Earth's Radiation Belts Observed by CALET on the International Space Station / A.W. Ficklin, A.B.. - In: POS PROCEEDINGS OF SCIENCE. - ISSN 1824-8039. - ELETTRONICO. - 501 - 39th International Cosmic Ray Conference (ICRC2025):(2025), pp. 0-0. (39th International Cosmic Ray Conference, ICRC 2025 Geneva, Switzerland 15-24 July 2025) [10.22323/1.501.1293].