Cosmic-ray lifetime in the galaxy: Experimental results and models

Simpson, J. A.; Garcia‐Munoz, M.

doi:10.1007/bf00212240

Cited by 83 publications

(53 citation statements)

References 25 publications

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“…However, the average densities in Table 2 based on their propagation appear to be lower than the average density of the overall ISM of the Galactic disk. Our results are consistent with but do not prove that there is significant propagation in the Galactic magnetic halo, as discussed by Simpson & Garcia-Munoz (1988) and Simpson & Connell (1998).…”

Section: Discussionsupporting

confidence: 55%

“…Simpson & Garcia-Munoz (1988), in their review of the implications for 10 Be, and, more recently, Simpson & Connell (1998) for 26 Al, pointed out substantial experimental evidence for a Galactic propagation model that includes propagation in both the halo and disk of the Galaxy. Nevertheless, the most highly developed model that can be tested quantitatively at this time, and compared by various investigators, is the so-called "leaky box" model with homogeneous distribution and propagation.…”

Section: The Galactic Propagation Modelmentioning

confidence: 99%

“…Radioactive nuclides detectable in the cosmic radiation are important investigative probes for determining the origin and propagation of cosmic rays in the Galaxy (e.g., Simpson & Garcia-Munoz 1988;Lukasiak et al 1994). From recent highresolution isotopic measurements of the secondary nuclides 10 Be and 26 Al, the average density of the interstellar medium through which the bulk of the primary and secondary cosmicray nuclei (i.e., to energies ≤1.5 GeV u Ϫ1 ) (note: ) u ϭ amu propagate, is 0.19 and 0.26 atoms cm…”

mentioning

confidence: 99%

See 2 more Smart Citations

The Cosmic-Ray Radioactive Nuclide [TSUP]36[/TSUP]C[CLC]l[/CLC] and Its Propagation in the Galaxy

Connell¹,

DuVernois²,

Simpson³

1998

The Astrophysical Journal

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Radioactive36 Cl has been resolved from 35 Cl and 37 Cl for the first time in the cosmic radiation with measurements obtained from the high-resolution High-Energy Telescope (HET) carried on the NASA-ESA Ulysses spacecraft. Within the framework of a homogeneous propagation model wherein all 36 Cl is of spallation origin, the average density of the interstellar gas r, through which all cosmic-ray nuclei propagate, was determined. Heliospheric modulation was included in the analysis.

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Section: Discussionsupporting

confidence: 55%

Section: The Galactic Propagation Modelmentioning

confidence: 99%

mentioning

confidence: 99%

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The Cosmic-Ray Radioactive Nuclide [TSUP]36[/TSUP]C[CLC]l[/CLC] and Its Propagation in the Galaxy

Connell¹,

DuVernois²,

Simpson³

1998

The Astrophysical Journal

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“…9: 2σ bands of the 10 Be/ 9 Be ratios for different propagation models. The observational data are from: Ulysses [51], ACE [14], Voyager [52], IMP [53], ISEE-3 [53], and ISOMAX [54].…”

Section: Discussionmentioning

confidence: 99%

Propagation of cosmic rays in the AMS-02 era

et al. 2017

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In this work we use the newly reported Boron-to-Carbon ratio (B/C) from AMS-02 and the time-dependent proton fluxes from PAMELA and AMS-02 to constrain the source and propagation parameters of cosmic rays in the Milky Way. A linear correlation of the solar modulation parameter with solar activities is assumed to account for the time-varying cosmic ray fluxes. A comprehensive set of propagation models, with/without reacceleration or convection, have been discussed and compared. We find that only the models with reacceleration can selfconsistently fit both the proton and B/C data. The rigidity dependence slope of the diffusion coefficient, δ, is found to be about 0.38 − 0.50 for the diffusion-reacceleration models. The plain diffusion and diffusionconvection models fit the data poorly. We compare different model predictions of the positron and antiproton fluxes with the data. We find that the diffusion-reacceleration models over-produce low energy positrons, while non-reacceleration models give better fit to the data. As for antiprotons, reacceleration models tend to underpredict low energy antiproton fluxes, unless a phenomenological modification of the velocity-dependence of the diffusion coefficient is applied. Our results suggest that there could be important differences of the propagation for nuclei and leptons, in either the Milky Way or the solar heliosphere.PACS numbers: 95.35.+d,96.50.S-

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“…The result (e.g., Simpson & Garcia-Munoz 1988;Lukasiak et al 1994;Connell 1998) is thatρ 0.3ρg, i.e., cosmic rays encounter a mean density about 1/3 of that of the interstellar medium in the disk (ng 1 cm −3 ). This is usually interpreted to mean that the cosmic rays spend a significant part of their lives outside of the disk and in the halo, where the gas density is much lower.…”

Section: Cosmic Ray Data and Energy Requirementsmentioning

confidence: 99%

Standard cosmic ray energetics and light element production

Fields

Olive

Cassé

et al. 2001

A&A

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Abstract. The recent observations of an approximately linear relationship between both Be and B and iron in metal-poor stars has led to a reassessment of the origin of the light elements in the early Galaxy. In addition to standard secondary production of BeB, it is necessary to introduce a production mechanism which is independent of the interstellar metallicity (primary), and in which freshly synthesized C, O and He are accelerated by supernova shock waves. Primary mechanisms are expected to be dominant at low metallicity. At metallicities higher than [O/H] > ∼ −1.75, some existing data indicate that secondary production is dominant. In this paper, we focus on the secondary process, related to the standard Galactic cosmic rays, and we examine the cosmic ray energy requirements for both present and past epochs. We find the power input to maintain the present-day Galactic cosmic ray flux is about 1.5 10 41 erg/s = 5 10 50 erg/century; this estimate includes energy losses from both the escape of high-energy particle and ionization losses from low-energy particles. This implies that, if supernovae are the sites of cosmic ray acceleration, the fraction of explosion energy going to accelerated particles is about ∼30%, a value which we obtain consistently both from considering the present cosmic ray flux and confinement and from the present 9 Be and 6 Li abundances. Using the abundances of 9 Be (and 6 Li) in metal-poor halo stars, we extend the analysis to show the effect of the interstellar gas mass on the standard Galactic cosmic ray energetic constraints on models of Li, Be, and B evolution. The efficiency of the beryllium production per erg may be enhanced in the past by a factor of about 10; thus the energetic requirement by itself cannot be used to rule out a secondary origin of light elements. Only a clear and indisputable observational determination of the O-Fe relation in the halo will discriminate between the two processes.

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Cosmic-ray lifetime in the galaxy: Experimental results and models

Cited by 83 publications

References 25 publications

The Cosmic-Ray Radioactive Nuclide [TSUP]36[/TSUP]C[CLC]l[/CLC] and Its Propagation in the Galaxy

The Cosmic-Ray Radioactive Nuclide [TSUP]36[/TSUP]C[CLC]l[/CLC] and Its Propagation in the Galaxy

Propagation of cosmic rays in the AMS-02 era

Standard cosmic ray energetics and light element production

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