The Origin of Primary Cosmic Rays: Constraints from ACE Elemental and Isotopic Composition Observations

Wiedenbeck, M. E.; Yanasak, N. E.; Cummings, A. C.; Davis, A. J.; George, Jimin; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.; Hink, P. L.; Israel, M. H.; Lijowski, M.; Christian, E. R.; Rosenvinge, T. T. von

doi:10.1007/978-94-017-3239-0_2

Cited by 18 publications

(12 citation statements)

References 17 publications

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“…which are described by a power law with an index ν A . In galprop, the primary source isotopic abundances are determined by fitting to the data from ACE at about 200 MeV/nucleon, based on a special propagation model [35,36]. But this appears some discrepancies when fit to some new data (see, e.g., Jóhannesson et al [37]), which covers high-energy regions.…”

Section: Setupsmentioning

confidence: 99%

Some new hints on cosmic-ray propagation from AMS-02 nuclei spectra

Niu

Xue

2020

J. Cosmol. Astropart. Phys.

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In this work, we considered 2 schemes (a high-rigidity break in primary source injections and a high-rigidity break in diffusion coefficient) to reproduce the newly released AMS-02 nuclei spectra (He, C, N, O, Li, Be, and B) when the rigidity larger than 50 GV. The fitting results show that current data set favors a high-rigidity break at ∼ 325 GV in diffusion coefficient rather than a break at ∼ 365 GV in primary source injections. Meanwhile, the fitted values of the factors to rescale the cosmic-ray (CR) flux of secondary species/components after propagation show us that the secondary flux are underestimated in current propagation model. It implies that we might locate in a slow diffusion zone, in which the CRs propagate with a small value of diffusion coefficient compared with the averaged value in the galaxy. Another hint from the fitting results show that extra secondary CR nuclei injection may be needed in current data set. All these new hints should be paid more attention in future research.

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Section: Setupsmentioning

confidence: 99%

Some new hints on cosmic-ray propagation from AMS-02 nuclei spectra

Niu

Xue

2020

J. Cosmol. Astropart. Phys.

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“…The LB elemental abundances are tuned simultaneously with spectra using the low energy part of the B/C ratio and isotopic abundances at 200 MeV/n from ACE (Wiedenbeck et al, 2001) and at 185 MeV/n from Ulysses (DuVernois and Thayer, 1996). For many elements ACE and Ulysses abundances differ by 10%.…”

Section: Abundances In Cosmic Rays and Cosmic Ray Sourcesmentioning

confidence: 99%

Propagation of secondary antiprotons and cosmic rays in the Galaxy

Moskalenko

Strong

Ormes

et al. 2005

Advances in Space Research

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Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratios (e.g., B/C) produce too few antiprotons. In the present paper we discuss one possibility to overcome these difficulties. Using the measured antiproton flux and B/C ratio to fix the diffusion coefficient, we show that the spectra of primary nuclei as measured in the heliosphere may contain a fresh local "unprocessed" component at low energies perhaps associated with the Local Bubble, thus decreasing the measured secondary to primary nuclei ratio. The independent evidence for SN activity in the solar vicinity in the last few Myr supports this idea. The model reproduces antiprotons, B/C ratio, and elemental abundances up to Ni (Z ≤ 28). Calculated isotopic distributions of Be and B are in perfect agreement with CR data. The abundances of three "radioactive clock" isotopes in CR, 10 Be, 26 Al, 36 Cl, are all consistent and indicate a halo size z h ∼ 4 kpc based on the most accurate data taken by the ACE spacecraft. INTRODUCTIONThe result of our recent analysis (Moskalenko et al., 2001b(Moskalenko et al., , 2002, in agreement with calculations of other authors (Molnar and Simon, 2001), was that matching the secondary/primary nuclei ratio B/C using reacceleration models leads to values of the spatial diffusion coefficient apparently too large to produce the requiredp flux, when the propagated nucleon spectra are tuned to match the local p and He flux measurements. Assuming the current heliospheric modulation models are approximately right, we have the following possibility (Moskalenko et al., 2003) to reconcile the B/C ratio with the measured flux of secondaryp's. The spectra of primary nuclei as measured in the heliosphere may contain a fresh local "unprocessed" component at low energies thus decreasing the measured secondary to primary nuclei ratio. This component would have to be local in the sense of being specific to the solar neighbourhood, so that the well-known "Local Bubble" phenomenon is a natural candidate.The low-density region around the Sun, filled with hot H I gas, is called the Local Bubble (hereafter LB) (?, e.g.,)]sfeir. The size of the region is about 200 pc, and it is likely that it was produced in a series of supernova (SN) explosions, with the last SN explosion occuring approximately 1-2 Myr ago, or 3 SN occuring within the last 5 Myr. Most probably its progenitor was an OB star association (?, e.g.,)]maiz,berghofer. Knie et al. (1999) report about an excess of 60 Fe measured in a deep ocean core sample of ferromanganese crust suggesting a SN explosion about 5 Myr ago at 30 pc distance and the deposition of SN-produced iron on earth. Sonett et al. (1987) report an enhancement in the CR intensity dated about 40 kyr ago, which is interpreted as the passage across the solar system of the shock wave from a SN exploding about 0.1 Myr ago. It could also be that "fresh" LB contribut...

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“…4, A and C ) and the right column ( Fig. 4, B and D ) are based on a conventional reacceleration model ( 58 , 59 ) and a plain diffusion model ( 59 ), respectively, of which the isotopic abundances have been tuned to reproduce those from the ACE observations ( 60 ). The subfigures in the upper row ( Fig.…”

Section: Resultsmentioning

confidence: 99%