Studies on Cosmic-Ray Nuclei with Voyager, ACE, and AMS-02. I. Local Interstellar Spectra and Solar Modulation

The acceleration of cosmic-ray particles and their propagation in the Milky Way and the heliosphere tangle with each other, leading to complexity and degeneracy of the modeling of Galactic cosmic rays (GCRs). The recent measurements of the GCR spectra by Voyager-1 from outside of the heliosphere gave the first direct observation of GCRs in the local interstellar (LIS) environment. Together with the high-precision data near the Earth taken by the Advanced Composition Explorer (ACE) and AMS-02, we derive the LIS spectra of helium, lithium, beryllium, boron, carbon, and oxygen nuclei from a few MeV n−1 to TeV n−1, using a non-parameterization method. These LIS spectra are helpful in further studying the injection and propagation parameters of GCRs. The nearly 20 years of data recorded by ACE are used to determine the solar modulation parameters over solar cycles 23 and 24, based on the force-field approximation. We find general agreements of the modulation potential with the results inferred from neutron monitors and other cosmic-ray data.

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