Our Latest Publication

Properties of Daily Helium Fluxes

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 $7.6 \times 10^8$ 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.

Phys. Rev. Lett. 128, 231102
Figure 1 , Figure 2 , Figure 3 , Figure 4

AMS-02 Publications

Total citations to-date: 5, 806
Published on
Properties of Daily Helium Fluxes
Phys. Rev. Lett. 128, 231102 (2022), View supplemental material and data
Published on
Periodicities in the Daily Proton Fluxes from 2011 to 2019 Measured by the Alpha Magnetic Spectrometer on the International Space Station from 1 to 100 GV
Phys. Rev. Lett. 127, 271102 (2021), Citations: 2, View supplemental material and data
Published on
Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen
Phys. Rev. Lett. 127, 021101 (2021), Citations: 4, View supplemental material and data
Published on Editors' Suggestion
Properties of Heavy Secondary Fluorine Cosmic Rays: Results from the Alpha Magnetic Spectrometer
Phys. Rev. Lett. 126, 081102 (2021), Citations: 19, View supplemental material and data
Published on
The Alpha Magnetic Spectrometer (AMS) on the International Space Station: Part II - Results from the First Seven Years
Phys. Rep. 894, 1 (2021), Citations: 80, View supplemental material and data
Published on Featured in Physics
Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer
Phys. Rev. Lett. 126, 041104 (2021), Citations: 31, View supplemental material and data
Published on Editors' Suggestion Featured in Physics
Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer
Phys. Rev. Lett. 124, 211102 (2020), Citations: 48, View supplemental material and data
Published on Editors' Suggestion
Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer
Phys. Rev. Lett. 123, 181102 (2019), Citations: 27, View supplemental material and data
Published on
Towards Understanding the Origin of Cosmic-Ray Electrons
Phys. Rev. Lett. 122, 101101 (2019), Citations: 103, View supplemental material and data
Published on Editors' Suggestion
Towards Understanding the Origin of Cosmic-Ray Positrons
Phys. Rev. Lett. 122, 041102 (2019), Citations: 177, View supplemental material and data
Published on
Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 121, 051103 (2018), Citations: 66, View supplemental material and data
Published on Editors' Suggestion
Observation of Complex Time Structures in the Cosmic-Ray Electron and Positron Fluxes with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 121, 051102 (2018), Citations: 66, View supplemental material and data
Published on
Observation of Fine Time Structures in the Cosmic Proton and Helium Fluxes with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 121, 051101 (2018), Citations: 80, View supplemental material and data
Published on Editors' Suggestion Featured in Physics
Observation of New Properties of Secondary Cosmic Rays Lithium, Beryllium, and Boron by the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 120, 021101 (2018), Citations: 182, View supplemental material and data
Published on
Observation of the Identical Rigidity Dependence of He, C, and O Cosmic Rays at High Rigidities by the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 119, 251101 (2017), Citations: 202, View supplemental material and data
Published on Editors' Suggestion Featured in Physics
Precision Measurement of the Boron to Carbon Flux Ratio in Cosmic Rays from 1.9 GV to 2.6 TV with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 117, 231102 (2016), Citations: 297, View supplemental material and data
Published on
Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 117, 091103 (2016), Citations: 462, View supplemental material and data
Published on Editors' Suggestion
Precision Measurement of the Helium Flux in Primary Cosmic Rays of Rigidities 1.9 GV to 3 TV with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 115, 211101 (2015), Citations: 427, View supplemental material and data
Published on Editors' Suggestion
Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 114, 171103 (2015), Citations: 767, View supplemental material and data
Published on
Precision Measurement of the (${\rm e}^+$ + ${\rm e}^−$) Flux in Primary Cosmic Rays from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 113, 221102 (2014), Citations: 331, View supplemental material and data
Published on Editors' Suggestion Featured in Physics
Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 113, 121102 (2014), Citations: 571, View supplemental material and data
Published on Editors' Suggestion
High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5 – 500 GeV with the Alpha Magnetic Spectrometer on the International Space Station
Phys. Rev. Lett. 113, 121101 (2014), Citations: 621, View supplemental material and data
Published on Editors' Suggestion Featured in Physics Physics Viewpoint
First Result from the Alpha Magnetic Spectrometer on the International Space Station: Precision Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5–350 GeV
Phys. Rev. Lett. 110, 141102 (2013), Citations: 1,243, View supplemental material and data

* Citation information from High-Energy Physics Literature Database.