Charge-sign dependent drift effects in the time-lag of cosmic-ray variation relative to solar activity observed with CALET
Year: 2026
Type: article
Abstract: The 11-yr variation of galactic cosmic-ray flux lags behind the variation of the sunspot number. An average ∼1-yr time-lag is expected from the outward propagating solar wind with the frozen-in photospheric magnetic field varying in the solar cycle, and from the inward diffusive transport of cosmic-ray particles. The long-term neutron monitor data, however, show that the time-lag is significantly longer (shorter) in the odd (even) solar cycle. In this paper, we analyze the time-lag in proton and electron fluxes observed by the Calorimetric Electron Telescope (CALET). It is found that the time-lag is similar in proton and electron fluxes during an A > 0 polarity epoch of the solar dipole magnetic field. In an even solar cycle 24 including a polarity reversal from A < 0 to A > 0, on the other hand, it is found that the time-lag of proton (electron) flux variation is significantly shorter (longer) than the average ∼1-yr lag by analyzing the combined data with CALET and AMS-02. This is the first observation of the charge-sign dependent time-lag. We demonstrate that these observations can be qualitatively interpreted in terms of different 11-yr time profiles of proton and electron fluxes in A > 0 and A < 0 epochs expected from the drift effect.
DOI: 10.13016/m26oye-usgq
Authors: Adriani, O, Akaike, Y, Asano, K, Asaoka, Y, Berti, E, Betti, P, Bigongiari, G, Binns, W R, Blum, L W, Bongi, M, Brogi, P, Bruno, A, Cannady, N, Castellini, G, Checchia, C, Cherry, M L, Collazuol, G, de Nolfo, G A, Ebisawa, K, Ficklin, A W, Fuke, H, Gonzi, S, Guzik, T G, Hams, Thomas, Hibino, K, Ichimura, M, Israel, M H, Kasahara, K, Kataoka, J, Kataoka, R, Katayose, Y, Kato, C, Kato, Y, 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, Picquenot, A, Rauch, B F, Ricciarini, S B, Sakai, K, Sakamoto, T, Sasaki, M, Shimizu, Y, Shiomi, A, Spillantini, P, Stolzi, F, Sugita, S, Takita, M, Tamura, T, Teramoto, M, Terasawa, T, Torii, S, Tsunesada, Y, Uchihori, Y, Vannuccini, E, Wefel, J P, Yamaoka, K, Yanagita, S, Yoshida, A, Yoshida, K, Zober, W V, CALET Collaboration
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1220896492, ABSTRACT THE CALET (CALORIMETRIC ELECTRON TELESCOPE) MISSION TO THE ISS HAS BEEN UNDER DEVELOPMENT FOR THE PAST DECADE AS A JAPANESE LED INTERNATIONA, G2000598668, G2131571848, G2319172811, THIS IS A CO-I PROPOSAL THAT SHOULD BE CROSS-REFERENCED TO THE LOUISIANA STATE UNIVERSITY PROPOSAL TITLED "CALET: FLIGHT OPERATIONS AND DATA ANALYSIS, G3056662531, G4270588743, Long-term observations to study the origins of Galactic Cosmic Rays and search for Dark Matter with CALET, G5692548517, Establishing a new concept in cosmic ray physics from the Earth and Heliosphere to the Milky Way through long-term CALET observations, Research on the Acceleration and Propagation of Cosmic Rays by High-precision Direct Observation, G8135020980, Search for nearby sources and dark matter signatures by precise measurement of cosmic-ray electrons in the TeV region
OpenAlex ID: W7141460884