The Cosmic Ray Helium and Carbon Nuclei Spectra Measured by Voyager 1 at Low Energies and Earth Based Measurements of these Nuclei up to 200 GeV nuc Concordance at High Energies with a Leaky Box Propagation Model
| Autor: | Webber, W. R., Higbie, P. R. |
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| Rok vydání: | 2015 |
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| Druh dokumentu: | Working Paper |
| Popis: | A comparison of the Helium and Carbon interstellar spectra measured at Voyager in the local interstellar medium leads to a different interpretation than a comparison of the Hydrogen to Helium spectra. This is because the He/C ratio is observed to increase rapidly with energy below 40 MeV/nuc in contrast to an almost constant H/He ratio at these low energies. Both the He and C spectra that are observed at Voyager above 40 MeV/nuc and much higher energy spectra from the PAMELA measurements of these two components up to 100 GeV/nuc can be accurately fit to within 10% assuming galactic propagation in a leaky box type of diffusion model in the galaxy with identical source spectra P-2.28 for He and C using a diffusion coefficient P0.50 above 1 GV rigidity. These same exponents also fit the H spectrum from 40 MeV to over 100 GeV. At low energies an excess of He relative to C is observed that would amount to about 20% of the modeled galactic component at 10 MeV/nuc. Comment: 12 pages, 2 figures |
| Databáze: | arXiv |
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