Local interstellar spectra and solar modulation of cosmic ray electrons and positrons

Abstract

Low energy cosmic rays are modulated by the solar activity when they propagation in the heliosphere, leading to ambiguities in understanding their acceleration at sources and propagation in the Milky Way. By means of the precise measurements of the $e^{-}$, $e^{+}$, $e^{-}+e^{+}$, and $e^{+}/(e^{-}+e^{+})$ spectra by AMS-02 near the Earth, as well as the very low energy measurements of the $e^{-}+e^{+}$ fluxes by Voyager-1 far away from the Sun, we derive the local interstellar spectra (LIS) of $e^{-}$ and $e^{+}$ components individually. Our method is based on a non-parametric description of the LIS of $e^{-}$ and $e^{+}$ and a force-field solar modulation model. We then obtain the evolution of the solar modulation parameters based on the derived LIS and the monthly fluxes of cosmic ray $e^{-}$ and $e^{+}$ measured by AMS-02. {\bf To better fit the monthly data, additional renormalization factors for $e^{-}$ and $e^{+}$ have been multiplied to the modulated fluxes.} We find that the inferred solar modulation parameters of positrons are in good agreement with that of cosmic ray nuclei, and the time evolutions of the solar modulation parameters of electrons and positrons differ after the reversal of the heliosphere magnetic field polarity, which shows clearly the charge-sign dependent modulation effect.

12 pages, 8 figures

References in corpus (10)

• Observation of an anomalous positron abundance in the cosmic radiation
• Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons
• Discrepant hardening observed in cosmic-ray elemental spectra
• The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
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• On Polar Magnetic Field Reversal and Surface Flux Transport During Solar Cycle 24
• Quantitative study of the AMS-02 electron/positron spectra: implications for the pulsar and dark matter properties
• New very local interstellar spectra for electrons, positrons, protons and light cosmic ray nuclei
• Time dependence of the electron and positron components of the cosmic radiation measured by the PAMELA experiment between July 2006 and December 2015
• Testing diffusion of cosmic rays in the heliosphere with proton and helium data from AMS

Cited by in corpus (8)

• Explaining the GeV antiproton/$\gamma -$ray excesses and W-boson mass anomaly in an inert two Higgs doublet model
• Observations of Forbush Decreases of cosmic ray electrons and positrons with the Dark Matter Particle Explorer
• Local interstellar spectra and solar modulation of cosmic ray proton and Helium
• Solar modulation of AMS-02 daily proton and Helium fluxes with modified force field approximation models
• Constraining Time Dependent Dark Matter Signals from the Sun
• Forecasting of the time-dependent fluxes of antiprotons in the AMS-02 era
• Probing solar modulation of AMS-02 time-dependent D, ${}^3$He and ${}^4$He fluxes with modified force field approximation
• Diverse properties of electron Forbush decreases revealed by the Dark Matter Particle Explorer