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Observations of Hydrogen and Helium Isotopes in Solar Cosmic Rays

Hurford, G. J. and Stone, E. C. and Vogt, R. E. (1975) Observations of Hydrogen and Helium Isotopes in Solar Cosmic Rays. In: Proceedings of the 14th International Cosmic Rays Conference. Vol.5. Max Planck Gesellschaft , pp. 1624-1629.

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Hydrogen and helium isotopes in solar cosmic rays between 1.2 and 15.0 MeV/nuc have been observed with the Ca1tech Electron/Isotope Spectrometer on IMP-7. During 1973 three "^3He rich events", containing more ^3He than ^2H or ^3H, were observed on 14 February, 29 June, and 5 September. The latter event was particularly interesting in that (^3He/^4He) ~ 6 and (^3He/^1H) ~ 1. Excluding these three events, flare-averaged ratios for ^2H/^1H and ^3H/^1H have been obtained for energies below 8.6 MeV/nuc. When compared with the ratios at higher energies, the observed energy dependence is consistent with the thin target model of Ramaty and Kozlovsky with a relativistic pathlength of ~ 1 g/cm^2. Flare-averaged ^3He results reported here might suggest a somewhat longer pathlength.

Item Type:Book Section
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Stone, E. C.0000-0002-2010-5462
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Additional Information:© 1975 MPE. Provided by the NASA Astrophysics Data System. This work was supported in part by the National Aeronautics and Space Administration under contract NAS5-11066 and grant NGR 05-002-160.
Group:Space Radiation Laboratory
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NASANGR 05-002-160
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Space Radiation Laboratory1975-06
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Deposited On:14 Apr 2014 23:53
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