scholarly journals The contribution of nearby supernova remnants on the cosmic ray flux at Earth

2020 ◽  
Vol 493 (2) ◽  
pp. 1960-1981
Author(s):  
A A L-Zetoun ◽  
A Achterberg
Keyword(s):  
Cosmic Rays ◽  
Anisotropic Diffusion ◽  
Supernova Remnants ◽  
Three Dimensional ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Source Position ◽  
Galactic Magnetic Field ◽  
The Earth ◽  
Cosmic Ray Flux

ABSTRACT We consider anisotropic diffusion of Galactic cosmic rays in the Galactic magnetic field, using the Jansson–Farrar model for the field. In this paper, we investigate the influence of source position on the cosmic ray flux at the Earth in two ways: (1) by considering the contribution from cosmic ray sources located in different intervals in Galactocentric radius, and (2) by considering the contribution from a number of specific and individual close-by supernova remnants. Our calculation is performed by using a fully three-dimensional stochastic method. This method is based on the numerical solution of a set of stochastic differential equations, equivalent to Itô formulation, that describes the propagation of the Galactic cosmic rays.

scholarly journals Short- and Medium-Term Induced Ionization in the Earth Atmosphere by Galactic and Solar Cosmic Rays

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Alexander Mishev
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
Galactic Cosmic Rays ◽  
Earth Atmosphere ◽  
Medium Term ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
The Earth ◽  
Ionization Effect

The galactic cosmic rays are the main source of ionization in the troposphere of the Earth. Solar energetic particles of MeV energies cause an excess of ionization in the atmosphere, specifically over polar caps. The ionization effect during the major ground level enhancement 69 on January 20, 2005 is studied at various time scales. The estimation of ion rate is based on a recent numerical model for cosmic-ray-induced ionization. The ionization effect in the Earth atmosphere is obtained on the basis of solar proton energy spectra, reconstructed from GOES 11 measurements and subsequent full Monte Carlo simulation of cosmic-ray-induced atmospheric cascade. The evolution of atmospheric cascade is performed with CORSIKA 6.990 code using FLUKA 2011 and QGSJET II hadron interaction models. The atmospheric ion rate is explicitly obtained for various latitudes, namely, 40°N, 60°N and 80°N. The time evolution of obtained ion rates is presented. The short- and medium-term ionization effect is compared with the average effect due to galactic cosmic rays. It is demonstrated that ionization effect is significant only in subpolar and polar atmosphere during the major ground level enhancement of January 20, 2005. It is negative in troposphere at midlatitude, because of the accompanying Forbush effect.

A reevaluation of the atmospheric pressure dependence of secondary cosmic-ray neutrons in the context of Cosmic-Ray Neutron Sensing

2021 ◽  
Author(s):  
Jannis Weimar ◽  
Paul Schattan ◽  
Martin Schrön ◽  
Markus Köhli ◽  
Rebecca Gugerli ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Hydrogen Content ◽  
Atmospheric Pressure ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Atmospheric Air ◽  
Neutron Intensity ◽  
The Earth ◽  
Wide Range ◽  
Primary Cosmic Rays

<p><span>Secondary cosmic-ray neutrons may be effectively used as a proxy for environmental hydrogen content at the hectare scale. These neutrons are generated mostly in the upper layers of the atmosphere within particle showers induced by galactic cosmic rays and other secondary particles. Below 15 km altitude their intensity declines as primary cosmic rays become less abundant and the generated neutrons are attenuated by the atmospheric air. At the earth surface, the intensity of secondary cosmic-ray neutrons heavily depends on their attenuation within the atmosphere, i.e. the amount of air the neutrons and their precursors pass through. Local atmospheric pressure measurements present an effective means to account for the varying neutron attenuation potential of the atmospheric air column above the neutron sensor. Pressure variations possess the second largest impact on the above-ground epithermal neutron intensity. Thus, using epithermal neutrons to infer environmental hydrogen content requires precise knowledge on how to correct for atmospheric pressure changes.</span></p><p><span>We conducted several short-term field experiments in saturated environments and at different altitudes, i.e. different pressure states to observe the neutron intensity pressure relation over a wide range of pressure values. Moreover, we used long-term measurements above glaciers in order to monitor the local dependence of neutron intensities and pressure in a pressure range typically found in Cosmic-Ray Neutron Sensing. The results are presented along with a broad Monte Carlo simulation campaign using MCNP 6. In these simulations, primary cosmic rays are released above the earth atmosphere at different cut-off rigidities capturing the whole evolution of cosmic-ray neutrons from generation to attenuation and annihilation. The simulated and experimentally derived pressure relation of cosmic-ray neutrons is compared to those of similar studies and assessed in the light of an appropriate atmospheric pressure correction for Cosmic-Ray Neutron Sensing.</span></p>

A New Determination of Muon Directional Coupling Coefficients

1968 ◽  
Vol 1 (4) ◽  
pp. 154-157
Author(s):  
D. J. Cooke ◽  
A. G. Fenton
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Cosmic Ray ◽  
Accurate Information ◽  
Coupling Coefficients ◽  
The Earth ◽  
Directional Coupling ◽  
Cosmic Ray Flux ◽  
Primary Cosmic Rays

Primary cosmic rays passing through the solar system carry with them valuable information about solar and astrophysical phenomena in the form of intensity and spectral variations. In order that this information be efficiently extracted from observations of the directional cosmic-ray flux at the surface of the Earth, it is essential to have accurate information available to enable the relating of the observed secondary cosmic-ray directions of motion and intensity to those outside the range of the disturbing terrestrial influences.

scholarly journals Cosmic ray spectra in planetary atmospheres

2008 ◽  
Vol 4 (S257) ◽  
pp. 471-473
Author(s):  
M. Buchvarova ◽  
P. Velinov
Keyword(s):  
Experimental Data ◽  
Solar Cycle ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Planetary Atmospheres ◽  
Galactic Cosmic Rays ◽  
Outer Planets ◽  
Practical Possibility ◽  
The Earth ◽  
Theoretical Results

AbstractOur model generalizes the differential D(E) and integral D(>E) spectra of cosmic rays (CR) during the 11-year solar cycle. The empirical model takes into account galactic (GCR) and anomalous cosmic rays (ACR) heliospheric modulation by four coefficients. The calculated integral spectra in the outer planets are on the basis of mean gradients: for GCR – 3%/AU and 7%/AU for anomalous protons. The obtained integral proton spectra are compared with experimental data, the CRÈME96 model for the Earth and theoretical results of 2D stochastic model. The proposed analytical model gives practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component.

scholarly journals Gamma-ray emitting supernova remnants as the origin of Galactic cosmic rays

2015 ◽  
Vol 2 ◽  
pp. 57-62 ◽  
Author(s):  
M. Kroll ◽  
J. Becker Tjus ◽  
B. Eichmann ◽  
N. Nierstenhöfer
Keyword(s):  
Cosmic Rays ◽  
Energy Budget ◽  
Thermal Energy ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Below The Knee ◽  
Individual Contributions ◽  
First Time

Abstract. It is generally believed that the cosmic ray spectrum below the knee is of Galactic origin, although the exact sources making up the entire cosmic ray energy budget are still unknown. Including effects of magnetic amplification, Supernova Remnants (SNR) could be capable of accelerating cosmic rays up to a few PeV and they represent the only source class with a sufficient non-thermal energy budget to explain the cosmic ray spectrum up to the knee. Now, gamma-ray measurements of SNRs for the first time allow to derive the cosmic ray spectrum at the source, giving us a first idea of the concrete, possible individual contributions to the total cosmic ray spectrum. In this contribution, we use these features as input parameters for propagating cosmic rays from its origin to Earth using GALPROP in order to investigate if these supernova remnants reproduce the cosmic ray spectrum and if supernova remnants in general can be responsible for the observed energy budget.

scholarly journals Direct Numerical Simulations of Cosmic-ray Acceleration at Dense Circumstellar Medium: Magnetic-field Amplification and Maximum Energy

2021 ◽  
Vol 922 (1) ◽  
pp. 7
Author(s):  
Tsuyoshi Inoue ◽  
Alexandre Marcowith ◽  
Gwenael Giacinti ◽  
Allard Jan van Marle ◽  
Shogo Nishino
Keyword(s):  
Cosmic Rays ◽  
Mass Loss ◽  
Supernova Remnants ◽  
Mass Loss Rate ◽  
Spherical Geometry ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Maximum Energy ◽  
Blast Waves ◽  
Loss Rates

Abstract Galactic cosmic rays are believed to be accelerated at supernova remnants. However, whether supernova remnants can be PeV is still very unclear. In this work we argue that PeV cosmic rays can be accelerated during the early phase of a supernova blast-wave expansion in dense red supergiant winds. We solve in spherical geometry a system combining a diffusive–convection equation that treats cosmic-ray dynamics coupled to magnetohydrodynamics to follow gas dynamics. A fast shock expanding in a dense ionized wind is able to trigger fast, non-resonant streaming instability over day timescales and energizes cosmic rays even under the effect of p–p losses. We find that such environments produce PeV blast waves, although the maximum energy depends on various parameters such as the injection rate and mass-loss rate of the winds. Multi-PeV energies can be reached if the progenitor mass-loss rates are of the order of 10−3 M ⊙ yr−1. It has been recently proposed that, prior to the explosion, hydrogen-rich massive stars can produce enhanced mass-loss rates. These enhanced rates would then favor the production of a PeV phase in early times after shock breakout.

Effects of ICMEs on High Energetic Particles as Observed by the Global Muon Detector Network (GMDN)

2017 ◽  
Vol 13 (S335) ◽  
pp. 69-74
Author(s):  
A. Dal Lago ◽  
C. R. Braga ◽  
R. R. S. de Mendonca ◽  
M. Rockenbach ◽  
E. Echer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Space Weather ◽  
Geomagnetic Storms ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Lead Times ◽  
Muon Detector ◽  
Crucial Importance ◽  
The Earth

AbstractThe Global Muon Detector Network (GMDN) is composed by four ground cosmic ray detectors distributed around the Earth: Nagoya (Japan), Hobart (Australia), Sao Martinho da Serra (Brazil) and Kuwait city (Kuwait). The network has operated since March 2006. It has been upgraded a few times, increasing its detection area. Each detector is sensitive to muons produced by the interactions of ~50 GeV Galactic Cosmic Rays (GCR) with the Earth′s atmosphere. At these energies, GCR are known to be affected by interplanetary disturbances in the vicinity of the earth. Of special interest are the interplanetary counterparts of coronal mass ejections (ICMEs) and their driven shocks because they are known to be the main origins of geomagnetic storms. It has been observed that these ICMEs produce changes in the cosmic ray gradient, which can be measured by GMDN observations. In terms of applications for space weather, some attempts have been made to use GMDN for forecasting ICME arrival at the earth with lead times of the order of few hours. Scientific space weather studies benefit the most from the GMDN network. As an example, studies have been able to determine ICME orientation at the earth using cosmic ray gradient. Such determinations are of crucial importance for southward interplanetary magnetic field estimates, as well as ICME rotation.

scholarly journals Supernova remnants and the origin of cosmic rays

2013 ◽  
Vol 9 (S296) ◽  
pp. 305-314
Author(s):  
Jacco Vink
Keyword(s):  
Synchrotron Radiation ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Long Time ◽  
Gamma Ray Emission

AbstractSupernova remnants have long been considered to be the dominant sources of Galactic cosmic rays. For a long time the prime evidence consisted of radio synchrotron radiation from supernova remnants, indicating the presence of electrons with energies of several GeV. However, in order to explain the cosmic ray energy density and spectrum in the Galaxy supernova remnant should use 10% of the explosion energy to accelerate particles, and about 99% of the accelerated particles should be protons and other atomic nuclei.Over the last decade a lot of progress has been made in providing evidence that supernova remnant can accelerate protons to very high energies. The evidence consists of, among others, X-ray synchrotron radiation from narrow regions close to supernova remnant shock fronts, indicating the presence of 10-100 TeV electrons, and providing evidence for amplified magnetic fields, gamma-ray emission from both young and mature supernova remnants. The high magnetic fields indicate that the condition for accelerating protons to >1015 eV are there, whereas the gamma-ray emission from some mature remnants indicate that protons have been accelerated.

scholarly journals Cosmic rays and stochastic magnetic reconnection in the heliotail

2012 ◽  
Vol 19 (3) ◽  
pp. 351-364 ◽  
Author(s):  
P. Desiati ◽  
A. Lazarian
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Reconnection ◽  
Supernova Remnants ◽  
Average Energy ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
The Galaxy

Abstract. Galactic cosmic rays are believed to be generated by diffusive shock acceleration processes in Supernova Remnants, and the arrival direction is likely determined by the distribution of their sources throughout the Galaxy, in particular by the nearest and youngest ones. Transport to Earth through the interstellar medium is expected to affect the cosmic ray properties as well. However, the observed anisotropy of TeV cosmic rays and its energy dependence cannot be explained with diffusion models of particle propagation in the Galaxy. Within a distance of a few parsec, diffusion regime is not valid and particles with energy below about 100 TeV must be influenced by the heliosphere and its elongated tail. The observation of a highly significant localized excess region of cosmic rays from the apparent direction of the downstream interstellar flow at 1–10 TeV energies might provide the first experimental evidence that the heliotail can affect the transport of energetic particles. In particular, TeV cosmic rays propagating through the heliotail interact with the 100–300 AU wide magnetic field polarity domains generated by the 11 yr cycles. Since the strength of non-linear convective processes is expected to be larger than viscous damping, the plasma in the heliotail is turbulent. Where magnetic field domains converge on each other due to solar wind gradient, stochastic magnetic reconnection likely occurs. Such processes may be efficient enough to re-accelerate a fraction of TeV particles as long as scattering processes are not strong. Therefore, the fractional excess of TeV cosmic rays from the narrow region toward the heliotail direction traces sightlines with the lowest smearing scattering effects, that can also explain the observation of a harder than average energy spectrum.

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