Steady State of Cosmic-Ray Nuclei—Their Spectral Shape and Path Length at Low Energies

1967 ◽  
Vol 158 (5) ◽  
pp. 1238-1242 ◽  
Author(s):  
R. Cowsik ◽  
Yash Pal ◽  
S. N. Tandon ◽  
R. P. Verma
Keyword(s):  
Steady State ◽  
Path Length ◽  
Cosmic Ray ◽  
Spectral Shape ◽  
Low Energies

Steady State of Cosmic-Ray Nuclei—Their Spectral Shape and Path Length at Low Energies

1968 ◽  
Vol 167 (5) ◽  
pp. 1545-1545
Author(s):  
R. Cowsik ◽  
Yash Pal ◽  
S. N. Tandon ◽  
R. P. Verma
Keyword(s):  
Steady State ◽  
Path Length ◽  
Cosmic Ray ◽  
Spectral Shape ◽  
Low Energies

scholarly journals Effects of the solar wind termination shock and heliosheath on theheliospheric modulation of galactic and anomalous Helium

2004 ◽  
Vol 22 (8) ◽  
pp. 3063-3072 ◽  
Author(s):  
U. W. Langner ◽  
M. S. Potgieter
Keyword(s):  
Solar Wind ◽  
Cosmic Ray ◽  
Magnetic Polarity ◽  
Termination Shock ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
Cosmic Ray Modulation ◽  
Low Energies ◽  
Solar Wind Termination Shock ◽  
Charge Sign

Abstract. The interest in the role of the solar wind termination shock and heliosheath in cosmic ray modulation studies has increased significantly as the Voyager 1 and 2 spacecraft approach the estimated position of the solar wind termination shock. The effect of the solar wind termination shock on charge-sign dependent modulation, as is experienced by galactic cosmic ray Helium (He++) and anomalous Helium (He+), is the main topic of this work, and is complementary to the previous work on protons, anti-protons, electrons, and positrons. The modulation of galactic and anomalous Helium is studied with a numerical model including a more fundamental and comprehensive set of diffusion coefficients, a solar wind termination shock with diffusive shock acceleration, a heliosheath and particle drifts. The model allows a comparison of modulation with and without a solar wind termination shock and is applicable to a number of cosmic ray species during both magnetic polarity cycles of the Sun. The modulation of Helium, including an anomalous component, is also done to establish charge-sign dependence at low energies. We found that the heliosheath is important for cosmic ray modulation and that its effect on modulation is very similar for protons and Helium. The local Helium interstellar spectrum may not be known at energies

Baryon production at LHC experiments: average pt of hyperons versus energy

2020 ◽  
Vol 35 (13) ◽  
pp. 2050067
Author(s):  
Olga I. Piskounova
Keyword(s):  
Cosmic Ray ◽  
String Model ◽  
Baryon Production ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Low Energies ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
The Difference ◽  
Proton Proton Collisions

This paper examines the transverse momentum spectra of baryons in the multiparticle production at modern colliders in the frameworks of Quark–Gluon String Model (QGSM). It discusses: (i) the difference in [Formula: see text] hyperon spectra at proton–antiproton versus proton–proton reactions on previous colliders; (ii) the difference in hyperon spectra between the experiments on colliders of low energies and the results from modern machines; (iii) the growth of average transverse momenta of [Formula: see text] hyperon with the energies of proton–proton collisions up to [Formula: see text] TeV of LHC experiments. This analysis of baryon spectra led to the following conclusions. First, the fragmentation of antidiquark–diquark side of one-pomeron diagram makes the major contribution to baryon production spectra in the asymmetric [Formula: see text] reaction. Second, the average [Formula: see text]’s of hyperons in [Formula: see text] collisions steadily grow with energy in the range from [Formula: see text] GeV to 7 TeV. The additional conclusion is the following: since no dramatic changes have been seen in the characteristics of baryon production, the hadroproduction processes do not cause the “knee” in the cosmic ray proton spectra at the energies between Tevatron collider and LHC.

Explanations of the spectral shape in the energy range 10 14 -10 20 eV

1975 ◽  
Vol 277 (1270) ◽  
pp. 429-442 ◽  
Keyword(s):  
Energy Spectrum ◽  
Energy Range ◽  
Cosmic Ray ◽  
Black Body ◽  
Spectral Shape

There is evidence suggesting an increase in slope of the energy spectrum of primary cosmic-ray nuclei at about 3 x 1015 eV. Alternative explanations are advanced for this change, related to diffusion of particles of galactic origin or black body cut-off effects for particles of extra-galactic origin. At higher energies there appear to be particles of energy up to 1020 eV. The evidence will be examined critically and alternative explanations put forward for the spectral shape in this region.

Survey of data on primary cosmic-ray nuclei above 10 14 eV

1975 ◽  
Vol 277 (1270) ◽  
pp. 413-428 ◽  
Keyword(s):  
Energy Spectrum ◽  
Cosmic Ray ◽  
Energetic Particles ◽  
Radius Of Curvature ◽  
Galactic Centre ◽  
Spectral Exponent ◽  
Upper Limit ◽  
Low Energies ◽  
Continuous Range ◽  
Arrival Directions

Primary cosmic-ray particles, detected by means of the extensive cascades they generate in the atmosphere, have been observed over a continuous range of energies up to 1020 eV, and apparently somewhat higher. At energies such that the radius of curvature of their trajectories, if they are protons, as expected, is comparable to our distance from the galactic centre, the arrival directions of 84 observed particles are distributed randomly over the sky. The energy spectrum of the particles shows an anomaly near 1015 eV, where the flux is higher than expected by extrapolation of data near 1012 eV, and then falls very rapidly (spectral exponent y » 3.5 at energies just above 4 x 1015 eV). Above 1017 eV the flux falls off less rapidly, y being near 3.0 in the range 1018 to 3 x 1019 eV. Extrapolating the flux back to low energies from 1018 eV, where the particles are often assumed to be of extra-galactic origin, gives a flux higher than that actually observed at low energies. The best evidence on energies of the large showers indicates that these are above 1020 eV, which is greater than the upper limit to which metagalactic protons could survive interactions with microwave photons. There is evidence that many of the most energetic particles (near 1018 eV) are indeed protons, but this result is only preliminary.

scholarly journals Cosmic rays and non-thermal emission in simulated galaxies: III. probing cosmic ray calorimetry with radio spectra and the FIR-radio correlation

2021 ◽  
Author(s):  
Maria Werhahn ◽  
Christoph Pfrommer ◽  
Philipp Girichidis
Keyword(s):  
Steady State ◽  
Star Formation ◽  
Thermal Emission ◽  
High Redshift ◽  
Formation Rate ◽  
Cosmic Ray ◽  
Far Infrared ◽  
Secondary Emission ◽  
Synchrotron Emission ◽  
Halo Masses

Abstract An extinction-free estimator of the star-formation rate (SFR) of galaxies is critical for understanding the high-redshift universe. To this end, the nearly linear, tight correlation of far-infrared (FIR) and radio luminosity of star-forming galaxies is widely used. While the FIR is linked to massive star formation, which also generates shock-accelerated cosmic ray (CR) electrons and radio synchrotron emission, a detailed understanding of the underlying physics is still lacking. Hence, we perform three-dimensional magneto-hydrodynamical (MHD) simulations of isolated galaxies over a broad range of halo masses and SFRs using the moving-mesh code Arepo, and evolve the CR proton energy density self-consistently. In post-processing, we calculate the steady-state spectra of primary, shock-accelerated and secondary CR electrons, which result from hadronic CR proton interactions with the interstellar medium. The resulting total radio luminosities correlate with the FIR luminosities as observed and are dominated by primary CR electrons if we account for anisotropic CR diffusion. The increasing contribution of secondary emission up to 30 per cent in starbursts is compensated by the larger bremsstrahlung and Coulomb losses. CR electrons are in the calorimetric limit and lose most of their energy through inverse Compton interactions with star-light and cosmic microwave background (CMB) photons while less energy is converted to synchrotron emission. This implies steep steady-state synchrotron spectra in starbursts. Interestingly, we find that thermal free–free emission flattens the total radio spectra at high radio frequencies and reconciles calorimetric theory with observations while free–free absorption explains the observed low-frequency flattening towards the central regions of starbursts.

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