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Volume 358 - 36th International Cosmic Ray Conference (ICRC2019) - SH - Solar & Heliospheric
Time dependence of the p/He ratio in cosmic rays according to the force-field approximation
C. Corti,* V. Bindi, C. Consolandi, C. Freeman, A. Kuhlman, C. Light, M. Palermo, S. Wang
*corresponding author
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Pre-published on: 2019 September 27
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We study the predictions for the p/He ratio in galactic cosmic rays according to the force-field approximation.
The dependence of the time variation of p/He on the local interstellar spectrum (LIS) shape and on the mass-to-charge ratio, $A/Z$, is analyzed in detail.
We find that, depending on the rigidity range and the sign of the spectral index of the p/He LIS ratio, the p/He time variation can be correlated or anti-correlated with the phase of the solar cycle.
We show that the $A/Z$ dependence is the most probable cause for the p/He decrease recently observed by AMS-02 after 2015 between 2 and 3 GV.
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