scholarly journals About the Altitude Profile of the Atmospheric Cut-Off of Cosmic Rays: New Revised Assessment

Solar Physics ◽  
2021 ◽  
Vol 296 (8) ◽  
Author(s):  
Alexander Mishev ◽  
Stepan Poluianov
Keyword(s):  
Cosmic Rays ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
High Energy ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Global Network ◽  
Joint Analysis ◽  
Cosmic Ray Intensity ◽  
Altitude Profile

AbstractCosmic rays, high-energy subatomic particles of extraterrestrial origin, are systematically measured by space-borne and ground-based instruments. A specific interest is paid to high-energy ions accelerated during solar eruptions, so-called solar energetic particles. In order to build a comprehensive picture of their nature, it is important to fill the gap and inter-calibrate ground-based and space-borne instruments. Here, we focus on ground-based detectors, specifically neutron monitors, which form a global network and provide continuous recording of cosmic ray intensity and its variability, used also to register relativistic solar energetic particles. The count rate of each neutron monitor is determined by the geomagnetic and atmospheric cut-offs, both being functions of the location. Here, on the basis of Monte Carlo simulations with the PLANETOCOSMICS code and by the employment of a new verified neutron monitor yield function, we assessed the atmospheric cut-off as a function of the altitude, as well as for specific stations located in the polar region. The assessed in this study altitude profile of the atmospheric cut-off for primary cosmic rays builds the basis for the joint analysis of strong solar proton events with different instruments and allows one to clarify recent definitions and related discussions about the new sub-class of events, so-called sub-ground-level enhancements (sub-GLEs).

scholarly journals Ulysses COSPIN observations of cosmic rays and solar energetic particles from the South Pole to the North Pole of the Sun during solar maximum

2003 ◽  
Vol 21 (6) ◽  
pp. 1217-1228 ◽  
Author(s):  
R. B. McKibben ◽  
J. J. Connell ◽  
C. Lopate ◽  
M. Zhang ◽  
J. D. Anglin ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Solar Maximum ◽  
Cosmic Ray ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Polar Regions ◽  
The Sun ◽  
The South ◽  
The North ◽  
Inner Heliosphere

Abstract. In 2000–2001 Ulysses passed from the south to the north polar regions of the Sun in the inner heliosphere, providing a snapshot of the latitudinal structure of cosmic ray modulation and solar energetic particle populations during a period near solar maximum.  Observations from the COSPIN suite of energetic charged particle telescopes show that latitude variations in the cosmic ray intensity in the inner heliosphere are nearly non-existent near solar maximum, whereas small but clear latitude gradients were observed during the similar phase of Ulysses’ orbit near the 1994–95 solar minimum. At proton energies above ~10 MeV and extending up to >70 MeV, the intensities are often dominated by Solar Energetic Particles (SEPs) accelerated near the Sun in association with intense solar flares and large Coronal Mass Ejections (CMEs). At lower energies the particle intensities are almost constantly enhanced above background, most likely as a result of a mix of SEPs and particles accelerated by interplanetary shocks. Simultaneous high-latitude Ulysses and near-Earth observations show that most events that produce large flux increases near Earth also produce flux increases at Ulysses, even at the highest latitudes attained. Particle anisotropies during particle onsets at Ulysses are typically directed outwards from the Sun, suggesting either acceleration extending to high latitudes or efficient cross-field propagation somewhere inside the orbit of Ulysses. Both cosmic ray and SEP observations are consistent with highly efficient transport of energetic charged particles between the equatorial and polar regions and across the mean interplanetary magnetic fields in the inner heliosphere.Key words. Interplanetary physics (cosmic rays) – Solar physics, astrophysics and astronomy (energetic particles; flares and mass ejections)

scholarly journals Energetic Particles in the Local Bubble

1997 ◽  
Vol 166 ◽  
pp. 177-186 ◽  
Author(s):  
G.E. Morfill ◽  
M.J. Freyberg
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Energetic Particles ◽  
Current Status ◽  
Length Variation ◽  
Local Bubble ◽  
Cosmic Ray Intensity ◽  
Interstellar Clouds ◽  
Proton Intensity ◽  
Path Lengths

AbstractThe current status of observations of energetic particles in the “local bubble” is reviewed. This includes primarily “direct” measurements of cosmic rays made in the Solar System, but also the “remote sensing” made possible by observing cosmic ray produced γ-rays in the nearby interstellar clouds. Since the energetic events responsible for the formation of our local bubble may also have produced copious amounts of cosmic rays, fossil records are examined to determine whether there is a corresponding signature. The observations show that: 1) the cosmic ray (proton) intensity is fairly homogeneous throughout the local bubble and its adjacent interstellar clouds, 2) there is some evidence for a “recent” local cosmic ray injection about 40,000 years ago, 3) on longer time scales (a few million years) the cosmic ray intensity was constant within a factor two, 4) there is apparently some “activity” in the Orion cloud, as evidenced by low energy γ-ray signatures, and 5) there are two unexplained observations – the variations in the energy spectra, in particular the significantly flatter spectrum of heavy cosmic rays (Fe) and the matter path length variation, which yields consistently larger path lengths for the lighter elements (H, He). It is suggested that these observations are compatible with two cosmic ray populations – an older one in equilibrium with losses from the galaxy and a younger one which is not yet strongly affected by losses. The latter could be a cosmic ray signature of the formation of the local bubble.

scholarly journals Current status and possible extension of the global neutron monitor network

2020 ◽  
Vol 10 ◽  
pp. 17
Author(s):  
Alexander Mishev ◽  
Ilya Usoskin
Keyword(s):  
Space Weather ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
Ground Level ◽  
Solar Proton ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Current Status ◽  
Flight Altitude ◽  
Ground Level Enhancements

The global neutron monitor network has been successfully used over several decades to study cosmic ray variations and fluxes of energetic solar particles. Nowadays, it is used also for space weather purposes, e.g. alerts and assessment of the exposure to radiation. Here, we present the current status of the global neutron monitor network. We discuss the ability of the global neutron monitor network to study solar energetic particles, specifically during large ground level enhancements. We demonstrate as an example, the derived solar proton characteristics during ground level enhancements GLE #5 and the resulting effective dose over the globe at a typical commercial jet flight altitude of 40 kft (≈12,200 m) above sea level. We present a plan for improvement of space weather services and applications of the global neutron monitor network, specifically for studies related to solar energetic particles, namely an extension of the existing network with several new monitors. We discuss the ability of the optimized global neutron monitor network to study various populations of solar energetic particles and to provide reliable space weather services.

scholarly journals Short-term periodicities observed in neutron monitor counting rates

2021 ◽  
pp. 65-71
Author(s):  
Alejandro López-Comazzi ◽  
Juan José Blanco
Keyword(s):  
Neutron Monitor ◽  
Spectral Power ◽  
Cosmic Ray ◽  
Global Network ◽  
Competitive Effect ◽  
Neutron Monitors ◽  
Short Term ◽  
Cosmic Ray Intensity ◽  
The One ◽  
First Time

The main objective is to check whether the periodicities observed in the cosmic rays in the interval 2013-2018 are affected by the magnetic rigidity or the height at which the neutron monitors are placed. A Global Neutron Monitor (GNM) has been defined as representative of the neutron monitor global network. The Morlet wave - let analysis is applied to the GNM and the selected solar activity parameters to find out common periodicities. Short-term periodicities of 13.5, 27, 48, 92, 132 and 298 days have been observed in cosmic ray intensity. A clear inverse relationship between rigidity and spectral power has been obtained for the 13.5, 48, 92, 132-day periods. A not so clear but still observed direct relationship between the height of the neutron monitors and the spectral power for the 48, 92, 132-day periods has been also found. The periodicity of 92 days is the one which shows the highest dependence with rigidity cutoff and height. As far as we know, this is the first time that these dependencies are reported. We think that these observations could be explained by assuming some cosmic ray intensity energy dependence in such periodicities and a competitive effect between rigidity and height.

scholarly journals High energy cosmic ray interactions and UHECR composition problem

2019 ◽  
Vol 210 ◽  
pp. 02001
Author(s):  
Sergey Ostapchenko
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Hadronic Interactions ◽  
High Energy Cosmic Rays ◽  
Cosmic Ray Interactions ◽  
Composition Problem

The differences between contemporary Monte Carlo generators of high energy hadronic interactions are discussed and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs) is studied. Key directions for further model improvements are outlined. The prospect for a coherent interpretation of the data in terms of the UHECR composition is investigated.

The results of simultaneous measurements of the cosmic-ray intensity over the Antarctic and Arctic

1968 ◽  
Vol 46 (10) ◽  
pp. S823-S824
Author(s):  
S. N. Vernov ◽  
A. N. Charakhchyan ◽  
T. N. Charakhchyan ◽  
Yu. J. Stozhkov
Keyword(s):  
Cosmic Rays ◽  
Temperature Effects ◽  
Cosmic Ray ◽  
Primary Component ◽  
Low Energy ◽  
Cosmic Ray Intensity ◽  
Simultaneous Measurements ◽  
Murmansk Region ◽  
The Antarctic

The results of the analysis of data obtained from measurements carried out by means of regular stratospheric launchings of cosmic-ray radiosondes over the Murmansk region and the Antarctic observatory in Mirny in 1963–66 are presented. The problem of the anisotropy of the primary component of low-energy cosmic rays and of temperature effects on the cosmic-ray intensity in the atmosphere are discussed.

scholarly journals On the Turbulent Reduction of Drifts for Solar Energetic Particles

2021 ◽  
Vol 922 (2) ◽  
pp. 200
Author(s):  
J. P. van den Berg ◽  
N. E. Engelbrecht ◽  
N. Wijsen ◽  
R. D. Strauss
Keyword(s):  
Pitch Angle ◽  
Cosmic Ray ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Particle Distributions ◽  
Magnetic Turbulence ◽  
Field Diffusion ◽  
Background Magnetic Field ◽  
Perpendicular Diffusion ◽  
Inner Heliosphere

Abstract Particle drifts perpendicular to the background magnetic field have been proposed by some authors as an explanation for the very efficient perpendicular transport of solar energetic particles (SEPs). This process, however, competes with perpendicular diffusion caused by magnetic turbulence, which can also disrupt the drift patterns and reduce the magnitude of drift effects. The latter phenomenon is well known in cosmic-ray studies, but not yet considered in SEP models. Additionally, SEP models that do not include drifts, especially for electrons, use turbulent drift reduction as a justification of this omission, without critically evaluating or testing this assumption. This article presents the first theoretical step for a theory of drift suppression in SEP transport. This is done by deriving the turbulence-dependent drift reduction function with a pitch-angle dependence, as is applicable for anisotropic particle distributions, and by investigating to what extent drifts will be reduced in the inner heliosphere for realistic turbulence conditions and different pitch-angle dependencies of the perpendicular diffusion coefficient. The influence of the derived turbulent drift reduction factors on the transport of SEPs are tested, using a state-of-the-art SEP transport code, for several expressions of theoretically derived perpendicular diffusion coefficients. It is found, for realistic turbulence conditions in the inner heliosphere, that cross-field diffusion will have the largest influence on the perpendicular transport of SEPs, as opposed to particle drifts.

Modelling the influence of high-energy radiation on the atmospheric composition of the hot Jupiter HD 189733b

2021 ◽  
Author(s):  
Patrick Barth ◽  
Christiane Helling ◽  
Eva E. Stüeken ◽  
Vincent Bourrier ◽  
Nathan Mayne ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Atmospheric Composition ◽  
Cloud Formation ◽  
Fine Grid ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Hot Jupiter

<p>Hot Jupiters provide valuable natural laboratories for studying potential contributions of high-energy radiation to prebiotic synthesis in the atmospheres of exoplanets. HD 189733b, a hot Jupiter orbiting a K star, is one of the most studied and best observed exoplanets. We combine XUV observations and 3D climate simulations to model the atmospheric composition and kinetic chemistry with the STAND2019 network. We show how XUV radiation, cosmic rays (CR), and stellar energetic particles (SEP) influence the chemistry of the atmosphere. We explore the effect that the change in the XUV radiation has over time, and we identify key atmospheric signatures of an XUV, CR, and SEP influx. 3D simulations of HD 189733b's atmosphere with the 3D Met Office Unified Model provide a fine grid of pressure-temperature profiles, consistently taking into account kinetic cloud formation. We apply <em>HST</em> and <em>XMM-Newton/Swift</em> observations obtained by the MOVES programmewhich provide combined X-ray and ultraviolet (XUV) spectra of the host star HD 189733 at 4 different points in time. We find that the differences in the radiation field between the irradiated dayside and the shadowed nightside lead to stronger changes in the chemical abundances than the variability of the host star's XUV emission. We identify ammonium (NH<sub>4</sub><sup>+</sup>) and oxonium (H<sub>3</sub>O<sup>+</sup>) as fingerprint ions for the ionization of the atmosphere by both galactic cosmic rays and stellar particles. All considered types of high-energy radiation have an enhancing effect on the abundance of key organic molecules such as hydrogen cyanide (HCN), formaldehyde (CH<sub>2</sub>O), and ethylene (C<sub>2</sub>H<sub>4</sub>). The latter two are intermediates in the production pathway of the amino acid glycine (C<sub>2</sub>H<sub>5</sub>NO<sub>2</sub>) and abundant enough to be potentially detectable by <em>JWST</em>. Ultimately, we show that high energy processes potentially play an important role in prebiotic chemistry.</p><p>P Barth et al., MOVES IV. Modelling the influence of stellar XUV-flux, cosmic rays, and stellar energetic particles on the atmospheric composition of the hot Jupiter HD 189733b, <em>Monthly Notices of the Royal Astronomical Society</em>, in press, DOI:10.1093/mnras/staa3989</p>

Correlation analysis of solar energetic particles and secondary cosmic ray flux

2021 ◽  
Vol 75 (6) ◽  
Author(s):  
Nikola Veselinović ◽  
Mihailo Savić ◽  
Aleksandar Dragić ◽  
Dimitrije Maletić ◽  
Radomir Banjanac ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Cosmic Ray ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Cosmic Ray Flux
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