Observation of Complex Time Structures in the Cosmic Ray Fluxes by the Alpha Magnetic Spectrometer on the ISS

TL;DR

This paper reports high-precision measurements of cosmic-ray fluxes by AMS over six years, revealing short-term structures and charge-sign dependent solar modulation effects in cosmic-ray particles.

Contribution

It provides the first detailed analysis of charge-sign dependent modulation during solar maximum using leptons alone, and observes short-term flux structures.

Findings

Detection of short-term flux structures on a monthly timescale.

Charge-sign dependent modulation observed during solar maximum.

Smooth transition of positron-to-electron flux ratio over ~800 days.

Abstract

We present high-statistics, precision measurements by AMS of the detailed time and rigidity dependence of the primary cosmic-ray electron, positron, proton and helium fluxes over 79 Bartels rotations from May 2011 to May 2017 in the energy range from 1 to 50 GeV. For the first time, the charge-sign dependent modulation during solar maximum has been investigated in detail by leptons alone. We report the observation of short-term structures on the timescale of months coincident in all the fluxes. These structures are not visible in the positron-to-electron flux ratio. The precision measurements across the solar polarity reversal show that the ratio exhibits a smooth transition over ~800 days from one value to another.