Cosmic rays in an evolving universe

1968 ◽  
Vol 46 (10) ◽  
pp. S623-S626 ◽  
Author(s):  
A. M. Hillas
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Proton Energy ◽  
Cosmic Ray ◽  
Long Period ◽  
The Past ◽  
Proton Energy Spectrum

If the most energetic cosmic rays that have been detected are of extragalactic origin, and their sources were strong radio emitters, the radio-astronomical evidence suggests that the output from such sources must have been very much greater in the past than at present, varying roughly as t−3 over a long period. In this case, the importance of interactions between the universal flux of microwaves and intergalactic cosmic-ray protons and nuclei above 1015 eV is greatly increased, because of "red shifts" in the energies of the nuclei and the microwaves, and changes in density. The probable result is shown to be a steepening in the proton energy spectrum from a slope of –1.5 to –2.2 over the range 1016 to 1018 eV, as is observed, if the energy spectrum at production is always simply E−1.5.This could mean that the "ankle" in the observed spectrum near 3 × 1018 eV is related to the interaction mentioned, and is not a transition from galactic to extragalactic rays.Difficulties remain in accounting for the spectrum above 3 × 1019 eV.

scholarly journals Proton energy spectrum with the DAMPE experiment

2019 ◽  
Vol 209 ◽  
pp. 01030 ◽  
Author(s):  
Antonio De Benedittis
Keyword(s):  
Dark Matter ◽  
Energy Spectrum ◽  
Cosmic Rays ◽  
Kinetic Energy ◽  
Elemental Composition ◽  
Proton Energy ◽  
Dark Matter Particle ◽  
Space Mission ◽  
Galactic Cosmic Rays ◽  
Proton Energy Spectrum

The DAMPE (DArk Matter Particle Explorer) experiment, in orbit since December 17th 2015, is a space mission whose main purpose is the detection of cosmic electrons and photons up to energies of 10 TeV, in order to identify possible evidence of Dark Matter in their spectra. Furthermore it aims to measure the spectra and the elemental composition of the galactic cosmic rays nuclei up to the energy of hundreds of TeV. The proton analysis and the flux with kinetic energy ranging from 50 GeV up to 100 TeV, at the end of two years of data taking, will be presented and discussed.

Atmospheric production and transport of 7Be activity by cosmic rays: Modelling with the chemistry-climate model SOCOLv3.0 and comparison with direct measurements

2021 ◽  
Author(s):  
Kseniia Golubenko ◽  
Eugene Rozanov ◽  
Genady Kovaltsov ◽  
Ari-Pekka Leppänen ◽  
Ilya Usoskin
Keyword(s):  
Cosmic Rays ◽  
Climate Changes ◽  
Climate Model ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Cosmogenic Isotopes ◽  
Cosmogenic Isotope ◽  
The Past ◽  
Direct Measurements ◽  
First Results

<p>We present the first results of modelling of the short-living cosmogenic isotope <sup>7</sup>Be production, deposition, and transport using the chemistry-climate model SOCOLv<sub>3.0</sub> aimed to study solar-terrestrial interactions and climate changes. We implemented an interactive deposition scheme,  based on gas tracers with and without nudging to the known meteorological fields. Production of <sup>7</sup>Be was modelled using the 3D time-dependent Cosmic Ray induced Atmospheric Cascade (CRAC) model. The simulations were compared with the real concentrations (activity) and depositions measurements of <sup>7</sup>Be in the air and water at Finnish stations. We have successfully reproduced and estimated the variability of the cosmogenic isotope <sup>7</sup>Be produced by the galactic cosmic rays (GCR) on time scales longer than about a month, for the period of 2002–2008. The agreement between the modelled and measured data is very good (within 12%) providing a solid validation for the ability of the SOCOL CCM to reliably model production, transport, and deposition of cosmogenic isotopes, which is needed for precise studies of cosmic-ray variability in the past. </p>

scholarly journals The highest-energy cosmic-rays – the past, the present and the future

2019 ◽  
Vol 210 ◽  
pp. 00001
Author(s):  
Alan Watson
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Mass Distribution ◽  
Mass Composition ◽  
Future Prospects ◽  
Telescope Array ◽  
Hadronic Interactions ◽  
The Past ◽  
Shower Maximum ◽  
The Mean

The greater part of this paper is concerned with a historical discussion of the development of the search for the origins of the highest-energy cosmic-rays together with a few remarks about future prospects.Additionally, in section 6, the situation with regard to the mass composition and energy spectrum at the highest energies is discussed. It is shown that the change of the depth of shower maximum with energy above 1 EeV, measured using the Telescope Array, is in striking agreement with similar results from the Auger Observatory. This implies that either the mean mass of cosmic rays is becoming heavier above ~4 EeV or that there is a change in details of the hadronic interactions in a manner such that protons masquerade as heavier nuclei. A long-standing controversy is thus resolved: the belief that pure protons dominate the mass distribution at the highest energies is no longer tenable.

scholarly journals On the correlation of the highest energy cosmic rays with AGNs

2009 ◽  
Vol 5 (H15) ◽  
pp. 251-253
Author(s):  
Vitor de Souza ◽  
Peter L. s Biermman
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Present Status ◽  
Cosmic Ray ◽  
Radio Galaxies ◽  
Pierre Auger Observatory ◽  
Heavy Nuclei ◽  
Measured Energy

AbstractIn this paper we briefly discuss the present status of the cosmic ray astrophysics under the light of the new data from the Pierre Auger Observatory. The measured energy spectrum is used to test the scenario of production in nearby radio galaxies. Within this framework the AGN correlation would require that most of the cosmic rays are heavy nuclei and are widely scattered by intergalactic magnetic fields.

scholarly journals The Pierre Auger Observatory: Review of Latest Results and Perspectives

Universe ◽  
2018 ◽  
Vol 4 (11) ◽  
pp. 128 ◽  
Author(s):  
Dariusz Góra ◽  
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Detection System ◽  
Cosmic Ray ◽  
High Energy ◽  
Pierre Auger Observatory ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Energy Limitation ◽  
Arrival Directions

The Pierre Auger Observatory is the world’s largest operating detection system for the observation of ultra high energy cosmic rays (UHECRs), with energies above 10 17 eV. The detector allows detailed measurements of the energy spectrum, mass composition and arrival directions of primary cosmic rays in the energy range above 10 17 eV. The data collected at the Auger Observatory over the last decade show the suppression of the cosmic ray flux at energies above 4 × 10 19 eV. However, it is still unclear if this suppression is caused by the energy limitation of their sources or by the Greisen–Zatsepin–Kuzmin (GZK) cut-off. In such a case, UHECRs would interact with the microwave background (CMB), so that particles traveling long intergalactic distances could not have energies greater than 5 × 10 19 eV. The other puzzle is the origin of UHECRs. Some clues can be drawn from studying the distribution of their arrival directions. The recently observed dipole anisotropy has an orientation that indicates an extragalactic origin of UHECRs. The Auger surface detector array is also sensitive to showers due to ultra high energy neutrinos of all flavors and photons, and recent neutrino and photon limits provided by the Auger Observatory can constrain models of the cosmogenic neutrino production and exotic scenarios of the UHECRs origin, such as the decays of super heavy, non-standard-model particles. In this paper, the recent results on measurements of the energy spectrum, mass composition and arrival directions of cosmic rays, as well as future prospects are presented.

The change in the energy spectrum of galactic cosmic rays over the 11-year solar activity cycle

1968 ◽  
Vol 46 (10) ◽  
pp. S927-S929
Author(s):  
Yu. Stozhkov ◽  
T. N. Charakhchyan
Keyword(s):  
Diffusion Coefficient ◽  
Solar Activity ◽  
Energy Spectrum ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Galactic Cosmic Rays ◽  
Ray Diffusion

The energy spectrum of galactic cosmic rays has been investigated for various periods of the solar activity. In the framework of commonly used ideas about the mechanism of the 11-year variation according to Parker the dependence of the cosmic-ray diffusion coefficient, D, on the particle rigidity, P, was determined. For the form D ≈ vpα the parameter α is found to change during the cycle of the solar activity.[Formula: see text]

scholarly journals Search for Annual 14C Excursions in the Past

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Fusa Miyake ◽  
Kimiaki Masuda ◽  
Toshio Nakamura ◽  
Katsuhiko Kimura ◽  
Masataka Hakozaki ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Tree Ring ◽  
Cosmic Ray ◽  
Solar Proton ◽  
The Past ◽  
Continuous Measurements ◽  
Pine Tree ◽  
Short Timescale ◽  
Bristlecone Pine ◽  
Solar Proton Events

AbstractTwo radiocarbon excursions (AD 774–775 and AD 993–994) occurred due to an increase of incoming cosmic rays on a short timescale. The most plausible cause of these events is considered to be extreme solar proton events (SPE). It is possible that there are other annual 14C excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the 14C contents in bristlecone pine tree-ring samples during the periods when the rate of 14C increase in the IntCal data is large. We analyzed four periods every other year (2479–2455 BC, 4055–4031 BC, 4465–4441 BC, and 4689–4681 BC), and found no anomalous 14C excursions during these periods. This study confirms that it is important to do continuous measurements to find annual cosmic-ray events at other locations in the tree-ring record.

The effects of the nature of matter traversed by cosmic rays on their composition and energy spectrum

1968 ◽  
Vol 46 (10) ◽  
pp. S512-S514
Author(s):  
M. V. K. Apparao ◽  
S. Ramadurai
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Neutral Hydrogen ◽  
Cosmic Ray ◽  
The State ◽  
Energy Spectra ◽  
Ionization Loss ◽  
Usual Assumption ◽  
Considerable Portion ◽  
Nature Of Matter

The effects of the state of ionization of the matter traversed by cosmic rays, and those due to the presence of helium in it, have been studied. The amount of matter traversed by cosmic rays expressed in g/cm2 deduced by the usual assumption that the matter traversed is all neutral hydrogen can be erroneous. The presence of helium increases this value, and a considerable portion of the matter is helium. The ionized (partial) nature of the matter increases the ionization loss of cosmic-ray nuclei. The effect of this on energy spectra has been demonstrated.

ONE DIMENSIONALITY OF DEUTERON VELOCITY DISTRIBUTION FOR CLUSTER-IMPACT FUSION

1992 ◽  
Vol 06 (10) ◽  
pp. 573-579 ◽  
Author(s):  
YEONG E. KIM ◽  
JIN-HEE YOON ◽  
ROBERT A. RICE ◽  
MARIO RABINOWITZ
Keyword(s):  
Energy Spectrum ◽  
Velocity Distribution ◽  
Proton Energy ◽  
Three Dimensional ◽  
Beam Direction ◽  
One Dimensional ◽  
Proton Energy Spectrum ◽  
Dimensional Distribution

In cluster-impact fusion, the width of the proton energy spectrum gives information about the temperature of the fusing deuterons, and its shape reflects the dimensionality of their velocity distribution. The observed symmetrical spectrum implies a one-dimensional distribution, whereas a three-dimensional distribution would result in a skewed spectrum. One dimensionality implies either extremely rapid thermalization in the beam direction, or the possibility of beam ion fusion.

scholarly journals Recent results from the Pierre Auger Observatory

2019 ◽  
Vol 208 ◽  
pp. 08001 ◽  
Author(s):  
Sergio Petrera
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Large Scale ◽  
Cosmic Ray ◽  
Pierre Auger Observatory ◽  
Mass Composition ◽  
Arrival Direction ◽  
Wide Range ◽  
Surface Detector

In this paper some recent results from the Pierre Auger Collaboration are presented. These are the measurement of the energy spectrum of cosmic rays over a wide range of energies (1017.5 to above 1020 eV), studies of the cosmic-ray mass composition with the fluorescence and surface detector of the Observatory, the observation of a large-scale anisotropy in the arrival direction of cosmic rays above 8 × 1018 eV and indications of anisotropy at intermediate angular scales above 4 × 1019 eV. The astrophysical implications of the spectrum and composition results are also discussed. Finally the progress of the upgrade of the Observatory, AugerPrime is presented.

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