Speaker
Description
We present the precision measurement of the daily proton and helium fluxes by AMS during 14.5 years of operation aboard the International Space Station. The measurements cover the rigidity ranges from 1 to 100 GV for protons and from 1.7 to 100 GV for helium. The observed fluxes exhibit variations on multiple time scales. On short time scales, recurrent periodicities of 27 are especially visible during the solar minimum of solar cycle 24. Non-recurrent variations of differing intensities are observed during solar maxima. Remarkably, below 2.4 GV, the hysteresis observed between the helium-to-proton flux ratio and the helium flux differs between solar maximum 24 and solar maximum 25. This indicates that, at low rigidity, the modulation of the helium-to-proton flux ratio varies before and after the solar maxima and across different solar cycles.
| 请选择分会 | 中微子物理、粒子天体物理与宇宙学 |
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