Neutron Monitor yield function: Improved spectral computations of the Forbush decrease of June 2015

Maria Livada, Loukas Xaplanteris, Nafsika Dimosthenous, Helen Mavromichalaki
Nuclear and Particle Physics Department, Faculty of Physics
National and Kapodistrian University of Athens
Zografos, 15784 Athens

The Forbush decrease of the cosmic ray intensity observed on June 2015 was chosen for cosmic ray spectral analysis. At first a study of the solar and geomagnetic parameters of this event is presented. Hourly cosmic ray data of the neutron monitor stations obtained from the high-resolution neutron monitor database (NMDB) were used for calculating the cosmic ray density and anisotropy variations.The cosmic ray spectral analysis during the Forbush decrease of June 2015 was performed following the technique of Wawrzynczak and Alania, 2010. Specifically in this technique the galactic cosmic ray spectral index was calculated using the coupling coefficient method that couples the secondary cosmic rays recorded at Earth to the primary cosmic ray flux at the edge of the magnetosphere. A newly presented yield function by Xaplanteris et al., 2021 based on the Quantum Field Theory (QFT) was applied for the spectral analysis of the Forbush decrease. A comparison of the obtained results during this event is performed by using the previous coupling function of Clem and Dorman (2000).

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