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Title: Cosmic-ray spectra of /sup 1/H, /sup 2/H, and /sup 4/He as a test of the origin of the hydrogen superfluxes at solar minimum modulation

Journal Article · · Astrophys. J.; (United States)
DOI:https://doi.org/10.1086/163311· OSTI ID:5375773

During the most recent (1972--1977) period of minimum solar modulation, it was discovered in the low-energy cosmic-ray spectra at 1 AU that (a) anomalous spectral components of /sup 4/He and heavier nuclei appeared; and (b) proton and helium ''superfluxes'' appeared which exceeded by up to 80% and 30%, respectively, the flux levels of the previous solar minimum in 1965. The simultaneous presence of these two phenomena has been investigated to determine whether the proton superflux is part of the proton galactic cosmic rays or is part of the anomalous nuclear components. The /sup 2/H//sup 1/H and the /sup 2/H//sup 4/He abundance ratios in the galactic cosmic rays at 56 MeV per nucleon are used as ''tracers'' to determine the origin of the proton superflux. These ratios, and the differential energy spectra of /sup 1/H, /sup 2/H, and He, were measured as a function of time and modulation level over a solar cycle with instruments on the IMP-class satellites. It is concluded that the superfluxes are of cosmic-ray origin and, at 1 AU, the result of reduced levels of residual modulation during the 1972--1977 solar minimum. They are not a significant part of the anomalous nuclear component.

Research Organization:
Enrico Fermi Institute, University of Chicago
OSTI ID:
5375773
Journal Information:
Astrophys. J.; (United States), Vol. 294:2
Country of Publication:
United States
Language:
English