time dependence of the p he ratio in cosmic rays according to the force field approximation

• DOI: 10.48550/arxiv.1910.01576
• Publication Date: 2019-09-27
• Authors: Christopher Freeman; C. Consolandi; Siqi Wang; Andrew Kuhlman; Christopher Light; Veronica Bindi; Matteo Palermo; Claudio Corti
• Keywords: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics; 13. Climate action; 0103 physical sciences; FOS: Physical sciences; Astrophysics - High Energy Astrophysical Phenomena; 01 natural sciences; Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)

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.<br/>Proceeding of the 36th International Cosmic Ray Conference (ICRC19)<br/>