Unique Properties of Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

Abstract

We present the latest results on primary cosmic rays Proton (p), Helium (He), Carbon(C), Oxygen (O), Neon (Ne), Magnesium (Mg), Silicon (Si), Sulfur (S), Iron (Fe), and Nickel (Ni) with the data collected by the Alpha Magnetic Spectrometer (AMS) during the first 10 years of operation on the International Space Station from May 19, 2011 to May 6, 2021. We found that the primary cosmic rays He-C-O and Ne-Mg-Si belong to the two different classes of cosmic rays. Above 80.5 GV, the rigidity dependence of the cosmic-ray Fe and Ni fluxes is identical to the rigidity dependence of the He, C, and O fluxes, showing that Fe and Ni are in the same class of He-C-O. And our latest result shows that S belongs to the Ne-Mg-Si class. We also found that the lightest and most abundant proton cosmic rays have two components—the first component being the same rigidity dependence as the He, C, and O fluxes and the second component with much softer rigidity dependence.