6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Solar modulation of cosmic ray antiprotons over the magnetic field reversal period

8 Jul 2026, 15:30
20m
Lecture Hall C3 (University of the Western Cape)

Lecture Hall C3

University of the Western Cape

Oral Presentation Track D - Astrophysics & Space Science Astrophysics & Space Science

Speaker

THABO MAHLATJI (NWU Student)

Description

The rigidity spectra of cosmic ray antiprotons and protons have been measured simultaneously, averaged over a Bartel rotation (~27 days), by AMS-02 detector between May 2011 and June 2022. These precise observations provide a more powerful context to study charge-sign-dependent modulation in the A < 0 magnetic cycle, through the period covering the solar magnetic field reversal, and in the A > 0 cycle. In this study, the previously established set of proton modulation parameters that reproduced AMS-02 proton observations between 2011 and 2019 is applied in our comprehensive physics-based 3D-drift numerical model to simulate modulated antiproton spectra over the same period as a function of time and rigidity. We find that, in agreement with our drift model results, the observed antiprotons to protons ratio reaches its maximum value during the magnetic field reversal period. This study will further highlight the importance of using the correct method of representing observational data points measured over a wide rigidity bin of finite width, especially when comparison with numerical computations is the intended end results.

Apply for student award at which level: MSc
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Author

THABO MAHLATJI (NWU Student)

Co-author

Donald Ngobeni (1. Department of Physical and Earth Sciences, Sol Plaatje University, Kimberley, South Africa. 2. Centre for Space Research, North-West University, Potchefstroom, South Africa.)

Presentation materials