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A. G. Tyumentsev

Publications and source records attributed to A. G. Tyumentsev.

8 recordsLinked to original sources
arXiv2017

Particle Spectra and Mass Composition in the Ultra-High Energy Region in the Framework of the Galactic Origin of Cosmic Rays

The possibility for a self-consistent description of all the basic features of the observed cosmic ray spectra and primary composition variations in the energy range of $10^{15}÷10^{20}$ eV within the Galactic origin scenario is examined. We assume the existence of Galactic sources that accelerate particles up to $\sim 3\cdot 10^{18}Z$ eV and take into account a highly inhomogeneous (fractal-like) distribution of matter and magnetic fields in the Galaxy that leads to extremely large free paths of particles ("Lévy flights"), along with an overwhelming contribution to the cosmic ray fluxes observed above $\sim 10^{18}$ eV from particles reaching the Solar System without scattering. Our scenario was refined on the basis of recent experimental results on primary mass composition. Model predictions, which could be verified with the improved high-precision measurements in the nearest future are discussed.

astro-ph.HE↗
arXiv2006

Energy spectrum and mass composition of primary cosmic rays around the `knee' in the framework of the model with two types of sources

Analysis of the experimental data on cosmic ray spectra in the framework of the proposed model with two types of sources leads to conclusion, that sources with particle generation spectral exponent $p\sim 2.85$ give the major contribution to the all-particle spectrum in the energy range $10^5-10^7$ GeV. `Fine structure' of spectrum around the `knee' may arise due to presence of nearby supernova type source, accelerating particles up to the energies $\sim3\cdot 10^4 Z$ GeV, if the energy output of such source is $\sim2\cdot10^{48}$ erg/source.

astro-ph↗
arXiv2005

Primary proton spectrum in the energy range $5-10^3$ TeV from the sea level muon spectrum

Primary proton spectrum in the energy range $5-10^3$ TeV is reconstructed from the sea level muon spectrum with the use of QGSJET01 and SYBILL2.1 interaction models. Heavier nuclei are taken in accordance with the direct measurements data, 100% uncertainty in helium flux is accounted for. The obtained proton intensity strongly contradicts to the available data of balloon experiments, exceeding them at the least by 100% for QGSJET01. This discrepancy is due to the combined effect of primary nucleon flux underestimation in the direct measurements and incorrect description of extensive air shower development. In the latter case it is required earlier shower development and harder spectra of secondary pions and kaons in comparison with QGSJET01. This conclusion is in agreement with the obtained by the KASCADE group on the basis of events rate study.

astro-ph↗
arXiv2005

On the deficit of calculated muon flux at sea level for energies $>100$ GeV

In this paper we discuss the problem, why the use of the direct data on primary nuclei spectra together with the modern hadronic interaction models leads to significant deficit of computed vertical muon flux at sea level for energies $>100$ GeV. We suggest, that to find out the source of this inconsistency it is necessary to perform an analysis of sensitivity of emulsion chamber data to variations of hadron-nucleus interaction characteristics. Such analysis will give more ground for discussion of adequacy of the up-to-date interaction models and of mutual compatibility of primary nuclei spectra, obtained in direct and EAS experiments.

astro-ph↗
arXiv2004

On inconsistency of experimental data on primary nuclei spectra with sea level muon intensity measurements

For the first time a complete set of the most recent direct data on primary cosmic ray spectra is used as input into calculations of muon flux at sea level in wide energy range $E_μ=1-3\cdot10^5$ GeV. Computations have been performed with the CORSIKA/QGSJET and CORSIKA/VENUS codes. The comparison of the obtained muon intensity with the data of muon experiments shows, that measurements of primary nuclei spectra conform to sea level muon data only up to several tens of GeV and result in essential deficit of muons at higher energies. As it follows from our examination, uncertainties in muon flux measurements and in the description of nuclear cascades development are not suitable to explain this contradiction, and the only remaining factor, leading to this situation, is underestimation of primary light nuclei fluxes. We have considered systematic effects, that may distort the results of the primary cosmic ray measurements with the application of the emulsion chambers. We suggest, that re-examination of these measurements is required with the employment of different hadronic interaction models. Also, in our point of view, it is necessary to perform estimates of possible influence of the fact, that sizable fraction of events, identified as protons, actually are antiprotons. Study of these cosmic ray component begins to attract much attention, but today nothing definite is known for the energies $>40$ GeV. In any case, to realize whether the mentioned, or some other reasons are the sources of disagreement of the data on primaries with the data on muons, the indicated effects should be thoroughly analyzed.

hep-ph↗
arXiv2003

Mass Composition of the Primary Cosmic Rays in the Energy Region 10^{14}-10^{20} eV in Anomalous Diffusion Model

We discuss the problem of cosmic ray mass composition variation in wide energy region 10^{14}-10^{20} eV. The mass composition predicted in the framework of recently developed anomalous diffusion model is tested using the results of CORSIKA calculations and experimental data on the depth of maximum of extensive air showers. We show that the model predictions for the mass composition are consistent with observations of different experiments.

astro-ph↗
arXiv2001

Anomalous diffusion of the cosmic rays: steady-state solution

We consider the propagation of galactic cosmic rays in the fractal interstellar medium. Steady state solution of the fractional diffusion equation, describing cosmic ray propagation, is found. We show that the exponent of the steady state spectrum turns out to be equal to the exponent of the cosmic ray spectrum above the "knee", that is approximately equal to 3.1.

astro-ph↗