Greifswald 2024 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 7: Sun and Heliosphere II

EP 7.6: Talk

Thursday, February 29, 2024, 15:15–15:30, ELP 6: HS 2

Charge sign dependence of recurrent Forbush Decreases in 2016 — •Lisa Romaneehsen, Johannes Marquardt, and Bernd Heber — Christian-Albrechts-Universität zu Kiel, Germany

This study investigates the periodicities of cosmic rays attributed to corotating interaction regions (CIRs) using AMS-02 data from late 2016 to early 2017. These data enable the first-time examination of recurrent Forbush decrease amplitudes induced by CIRs, considering rigidity and charge sign dependence. The findings from the Lomb-Scargle algorithm and Superposed Epoch Analysis were compared. Results reveal that the rigidity dependence of proton decreases attributed to the northern coronal hole aligns with existing literature, while that of the southern coronal hole does not. The amplitude of the Helium modulation exceeds that of protons, in line with previous observations. For positrons statistical limitation prevent definitive conclusions. In comparison to the positively charged ions the modulation behavior of electrons can not be understood in the current paradigma of modulation by diffusion barriers.

Keywords: Cosmic Rays; Corotating Interaction Regions; Cosmic Ray modulation; Forbush Decreases; Charge sign dependence