Abstract
We present high-statistics, precision measurements of the detailed time and energy dependence of the primary cosmic-ray electron flux and positron flux over 79 Bartels rotations from May 2011 to May 2017 in the energy range from 1 to 50GeV. For the first time, the charge-sign dependent modulation during solar maximum has been investigated in detail by leptons alone. Based on 23.5×10^{6} events, we report the observation of short-term structures on the timescale of months coincident in both the electron flux and the positron flux. These structures are not visible in the e^{+}/e^{-} flux ratio. The precision measurements across the solar polarity reversal show that the ratio exhibits a smooth transition over 830±30 days from one value to another. The midpoint of the transition shows an energy dependent delay relative to the reversal and changes by 260±30 days from 1 to 6GeV.
Highlights
We present high-statistics, precision measurements of the detailed time and energy dependence of the primary cosmic-ray electron flux and positron flux over 79 Bartels rotations from May 2011 to May 2017 in the energy range from 1 to 50 GeV
Based on 23.5 × 106 events, we report the observation of short-term structures on the timescale of months coincident in both the electron flux and the positron flux
The precision measurements across the solar polarity reversal show that the ratio exhibits a smooth transition over 830 Æ 30 days from one value to another
Summary
May 2017, based on 23.5 × 106 electron and positron events collected by the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station (ISS) These data allow comprehensive studies of the energy and charge-sign dependence of short-term effects on the time scale of months, related to solar activity [1,2], and long-term effects on the time scale of years, related to the 22 year cycle of the solar magnetic field [3]. The same energy binning as for Ref. [32] is used up to 49.33 GeV
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