Anisotropy of Cosmic Ray Fluxes Measured with the Alpha Magnetic Spectrometer on the ISS

Abstract

A measurement of the dipole anisotropy in galactic coordinates for different charged cosmic rays has been performed with the Alpha Magnetic Spectrometer (AMS) onboard the International Space Station (ISS). Results are presented for the first 7.5 years of data taking for protons, Helium, Carbon and Oxygen, and 6.5 years for positrons and electrons. All the species are found to be consistent with isotropy and upper limits to the dipole amplitude have been computed. In particular, for energies above 16 GeV a limit of delta < 1.9% and delta < 0.5% at the 95% C.I. is found for positrons and electrons respectively. For rigidities above 200 GV a limit of delta < 0.38%, delta < 0.36%, delta < 1.9% and delta < 1.7% is obtained for protons, Helium, Carbon and Oxygen.