The energy spectra of protons and helium measured with the ATIC experiment

Ahn, Ho Seok; Seo, E. S.; Adams, J. H.; Bashindzhagyan, G. L.; Batkov, K. E.; Chang, Jin; Christl, M.; Fazely, A. R.; Ganel, O.; Gunasingha, R. M.; Guzik, T. G.; Isbert, J.; Kim, K. C.; Kouznetsov, E. N.; Panasyuk, M. I.; Панов, А. Д.; Schmidt, Wolfgang; Sina, R.; Sokolskaya, N. V.; Wang, J. Z.; Wefel, J. P.; Wu, J.; Zatsepin, V. I.

doi:10.1016/j.asr.2005.09.031

Cited by 46 publications

(29 citation statements)

References 12 publications

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“…The essential exception is the measured in the recent ATIC-2 balloon experiment (Panov et al, 2006) helium spectrum, which opposite to the theoretical expectation is noticeably flatter than the protons spectrum. Note that the spectral shape of protons and helium measured in the previous ATIC-1 experiment at energies 10 − 10 4 GeV (Ahn et al, 2006) are very similar. Similar form of the spectra for different GCR nuclei at energies ǫ k = 10 3 − 10 6 GeV if observed could be considered as the indirect confirmation of GCR origin in SNRs.…”

Section: Maximum Energy Of Crssupporting

confidence: 56%

Cosmic ray acceleration by supernova shocks

Berezhko¹

2008

Advances in Space Research

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We analyse the results of recent measurements of nonthermal emission from individual supernova remnants (SNRs) and their correspondence to the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is shown that the theory fits these data in a satisfactory way and provides the strong evidences for the efficient CR production in SNRs accompanied by significant magnetic field amplification. Magnetic field amplification leads to considerable increase of CR maximum energy so that the spectrum of CRs accelerated in SNRs is consistent with the requirements for the formation of Galactic CR spectrum up to the energy ∼ 10 17 eV.

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Section: Maximum Energy Of Crssupporting

confidence: 56%

Cosmic ray acceleration by supernova shocks

Berezhko¹

2008

Advances in Space Research

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“…The ATIC spectrometer has measured both the spectrum and the composition of multi-TeV cosmic rays and found different spectra for the different species. We simulate the 8 species listed with their spectra measured by ATIC (Panov et al 2006;Ahn et al 2006) and fit to an overall offset in the spectral index (∆α) and a flux scale factor (S) where ∆α=0 indicates that the spectrum was measured to be exactly equal to the ATIC spectrum, ∆α >0 indicates a steeper spectrum and ∆α <0 indicates a flatter spectrum. Similarly, S=1 indicates an agreement with the predicted flux, S < 1 indicates that Milagro measures a flux that is less than the the predicted flux and S > 1 indicates a greater flux than predicted.…”

Section: Systematic Effectsmentioning

confidence: 99%

Observation and Spectral Measurements of the Crab Nebula With Milagro

Abdo

Allen

Atkins

et al. 2012

ApJ

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“…The first type is pertinent to the spectrum of the ratio of two different elements attributable to the same or similar accelerators. At least in one such case, the theory has already faced a serious challenge when a ∆q ≈ 0.1 difference be-tween the proton and helium rigidity spectra was firmly established (Ahn et al 2006;Adriani et al 2011;Aguilar et al 2015). Explanations have been given (see Serpico 2015; Malkov 2018 for a review), but only a few of them address the proton and helium spectra at the DSA level (see Hanusch et al 2019 and the references therein).…”

Section: Introductionmentioning

confidence: 99%

Steepening of Cosmic-Ray Spectra in Shocks with Varying Magnetic Field Direction

Hanusch

Liseykina

Malkov

et al. 2019

ApJ

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Cosmic ray (CR) spectra, both measured upon their arrival at the Earth's atmosphere and inferred from the emission in supernova remnants (SNRs), appear to be significantly steeper than the "standard" diffusive shock acceleration (DSA) theory predicts. Although the reconstruction of the primary spectra introduces an additional steepening due to propagation effects, there is a growing consensus in the CR community that these corrections fall short to explain the newest high-precision data. Using 2D hybrid simulations, we investigate a new mechanism that may steepen the spectrum during the acceleration in SNR shocks.Most of the DSA treatments are limited to homogeneous shock environments. To investigate whether inhomogeneity effects can produce the necessary extra steepening, we assume that the magnetic field changes its angle along the shock front. The rationale behind this approach is the strong dependence of the DSA efficiency upon the field angle, θ Bn . Our results show that the variation of shock obliquity along its face results in a noticeable steepening of the DSA spectrum. Compared to simulations of quasi-parallel shocks, we observe an increase of the spectral index by ∆q = 0.1 − 0.15. Possible extrapolation of the limited simulation results to more realistic SNR conditions are briefly considered.

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The energy spectra of protons and helium measured with the ATIC experiment

Cited by 46 publications

References 12 publications

Cosmic ray acceleration by supernova shocks

Cosmic ray acceleration by supernova shocks

Observation and Spectral Measurements of the Crab Nebula With Milagro

Steepening of Cosmic-Ray Spectra in Shocks with Varying Magnetic Field Direction

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