Precision measurement of cosmic-ray nuclei with the alpha magnetic spectrometer on the International Space Station

The measurement of the nuclei component in cosmic rays (CR) provides a detailed knowledge of the origin and propagation of cosmic rays. AMS-02 is a magnetic spectrometer designed to perform precision measurment of the composition and energy spectrum of cosmic rays from GeV to TeV. Using its large acceptance and long exposure time, AMS-02 is able to measure the fluxes of CR species at least up to iron, studying also the detailed variation of their spectral index as a function of the rigidity. AMS-02 was installed onboard the International Space Station on May 19, 2011 and has been continuously taking data since then. In 8 years of operations, it collected over 135 billion of cosmic-ray triggers, both primary and secondary. Primary cosmic rays, such as H, He, C, N and O, are mainly produced and accelerated by supernova explosions, while secondary cosmic rays, such as Li, Be and B are produced through collisions of heavier nuclei with the interstellar medium. In this contribution, the published results regarding the nuclear component of CR from hydrogen to oxygen, for rigidity interval between 2 GV and 3.3 TV, have been presented. The contribution will also show the preliminary measurement of the temporal evolution of carbon and oxygen fluxes, during the period between May 2011 and May 2018. This measurerement can provide important information about the propagation of CR inside the heliosphere.