@article{7c017b1a04dd4877b9489fef5cacee44,
title = "Properties of Daily Helium Fluxes",
abstract = "We present the precision measurement of 2824 daily helium fluxes in cosmic rays from May 20, 2011 to October 29, 2019 in the rigidity interval from 1.71 to 100 GV based on 7.6×108 helium nuclei collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The helium flux and the helium to proton flux ratio exhibit variations on multiple timescales. In nearly all the time intervals from 2014 to 2018, we observed recurrent helium flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. In the entire time period, we found that below ∼7 GV the helium flux exhibits larger time variations than the proton flux, and above ∼7 GV the helium to proton flux ratio is time independent. Remarkably, below 2.4 GV a hysteresis between the helium to proton flux ratio and the helium flux was observed at greater than the 7σ level. This shows that at low rigidity the modulation of the helium to proton flux ratio is different before and after the solar maximum in 2014.",
author = "\{(AMS Collaboration)\} and M. Aguilar and Cavasonza, \{L. Ali\} and G. Ambrosi and L. Arruda and N. Attig and F. Barao and L. Barrin and A. Bartoloni and \{Ba{\c s}eǧmez-Du Pree\}, S. and R. Battiston and M. Behlmann and J. Berdugo and B. Bertucci and V. Bindi and K. Bollweg and B. Borgia and Boschini, \{M. J.\} and M. Bourquin and Bueno, \{E. F.\} and Burger, \{W. J.\} and Burger, \{W. J.\} and S. Burmeister and Cai, \{X. D.\} and M. Capell and J. Casaus and G. Castellini and F. Cervelli and Chang, \{Y. H.\} and Chen, \{G. M.\} and Chen, \{G. R.\} and Chen, \{H. S.\} and Y. Chen and L. Cheng and Chou, \{H. Y.\} and S. Chouridou and V. Choutko and Chung, \{C. H.\} and C. Clark and G. Coignet and C. Consolandi and A. Contin and C. Corti and Z. Cui and K. Dadzie and A. Dass and C. Delgado and \{Della Torre\}, S. and Demirk{\"o}z, \{M. B.\} and L. Derome and \{Di Falco\}, S. and Liqiu Wang",
note = "Funding Information: We are grateful for important physics discussions with Igor Moskalenko. We thank former NASA Administrator Daniel S. Goldin for his dedication to the legacy of the International Space Station (ISS) as a scientific laboratory and his decision for NASA to fly AMS as a DOE payload. We also acknowledge the continuous support of the NASA leadership, particularly William H. Gerstenmaier, and of the JSC and MSFC flight control teams that have allowed AMS to operate optimally on the ISS for over ten years. We are grateful for the support of Jim Siegrist, Glen Crawford, and their staff of the DOE including resources from the National Energy Research Scientific Computing Center under Contract No. DE-AC02-05CH11231. We acknowledge the strong support from Fabiola Gianotti, DG of CERN, and the CERN IT department including Bernd Panzer-Steindel. We also acknowledge the continuous support from MIT and its School of Science, and the Laboratory for Nuclear Science, Boleslaw Wyslouch. Research supported by Chinese Academy of Sciences, Institute of High Energy Physics, Institute of Electrical Engineering, China Academy of Space Technology, National Natural Science Foundation, and Ministry of Science and Technology, the China Scholarship Council, the provincial governments of Shandong, Jiangsu, Guangdong, Shandong University, and the Shandong Institute of Advanced Technology, China; CNRS/IN2P3 and CNES, France; DLR under Grant No. 50OO1805 and computing support on the JARA Partition of the RWTH Aachen supercomputer, and DLR under Grant No. 50OC1804 at CAU, Germany; INFN and ASI under ASI-INFN Agreements No. 2014-037-R.1-2017 and No. 2019-19-HH.0 and ASI-University of Perugia Agreement No. 2019-2-HH.0, Italy; CHEP and NRF under Grant No. NRF-2018R1A6A1A06024970 at Kyungpook National University, Korea; the Consejo Nacional de Ciencia y Tecnolog{\'i}a and UNAM, Mexico; NWO under Grant No. 680-1-004, Netherlands; FCT under Grant No. CERN/FIS-PAR/0013/2019, Portugal; the Ministry of Science and Higher Education under Project No. 0723-2020-0040, Russia; CIEMAT, IAC, CDTI, and SEIDI-MINECO under Grants No. PID2019–107988 GB-C21/C22, No. CEX2019-000920-S, and No. MDM-2015-0509, Spain; federal and cantonal authorities and the Fondation Dr. Manfred Steuer, Switzerland; Academia Sinica and the Ministry of Science and Technology (MOST) under Grants No. 107-2119-M-006-015-MY3, No. 109-2112-M-001-029, and No. CDA-105-M06, former Presidents of Academia Sinica Yuan-Tseh Lee and Chi-Huey Wong and former Ministers of MOST Maw-Kuen Wu and Luo-Chuan Lee, Taiwan; the Turkish Energy, Nuclear and Mineral Research Agency (TENMAK) under Grants No. 2020TAEK(CERN)A5.H1.F5-26, Turkey; and NSF Grants No. 1455202 and No. 2013228, Wyle Laboratories Grant No. 2014/T72497, and NASA NESSF Grant No. HELIO15F-0005, USA. Publisher Copyright: {\textcopyright} 2022 authors. Published by the American Physical Society.",
year = "2022",
month = jun,
day = "10",
doi = "10.1103/PhysRevLett.128.231102",
language = "English",
volume = "128",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "23",
}